The Official AVS Antenna Topic! [Text View] - Page 19

holl_ands

05-22-06, 05:34 PM

> IF (and that's a very BIG IF) the ATSC Decoder chip can coherently add the
> various multipath components, then the resultant SNR could improve compared
> to only one or two fading paths....or a single non-fading path.

> In the Canadian Research Center (CRC) tests on the prototype Samsung ATSC Receiver,
...
> http://www.crc.ca/en/html/crc/home/research/broadcast/rtnt

Quite impressive.

Are there similar tests for 4th generation demodulators?
I poked around on crc.ca and also tried google, but couldn't find any.

From April, 2005:
} Generally speaking, leaves will attenuate signals, especially UHF,
} and if they are being blown by the wind, this attenuation is usually
} too variable for the automatic gain control module in your tuner to
} compensate for.

I didn't see any tests to see how the tuners/demodulators handle this
problem. :-(

I also didn't see anything that appeared to test for tuners/demodulators
ability to deal with transmitter differential gain error. :-(
The CRC tests are unique in that they actually name names---although the production
equipment may perform somewhat better (or worst) than the tested prototype.

A variety of lab and on-tests have been conducted, including the original Grand Alliance (GA)
double-conversion receiver and various 2nd and 3rd Gen receivers:

a. www.atsc.org lists numerous reports incl. fol. dated Dec 2000:
http://www.atsc.org/news_information/papers/2000_vsb_comparison_report/VSB_COFDM_Project_Comparison.pdf

b. Australia 1998 Test Report: ATSC vs DVB-T (dtbfield.doc) (30 pgs):
http://happy.emu.id.au/lab/info/digtv/files/

c. Brazil 2000 Test Report: ATSC vs DVB-T (119 pgs):
http://www.anatel.gov.br/english_site/publications/public_consultation/tvd_ranalises_ing.pdf

d. Summary of DVB-T (et. al.) Field Trials Around the World:
http://www.bjpace.com.cn/data/tec/tec-DVB/DVB%20Publications/DVB-T%20Field%20Trials%20Around%20the%20World.pdf

e. Zenith 2003: Excellent Summary of Commercial Broadcasters On-Air Tests (19 pgs):
http://www.zenith.com/digitalbroadcast/downloads/ATSC%20Field%20Test%20Results.pdf

f. Zenith 2003: ATSC Seminar--See on-air test summary towards end (265 pgs):
http://www.zenith.com/digitalbroadcast/downloads/Seminar%20Slides.pdf
[Everything you ever wanted to know about ATSC, but were afraid to ask....]

Tests on so-called 4th and 5th Gen receivers (i.e. LST-4200A and later) are very difficult
to interpret because manufacturer/model designations are generally missing.

Last year, an STB/HDTV receiver comparison test was conducted by MSTV for the FCC,
wherein there were found to be big differences between some high performance tuners
(probably LG 5th Gen & ATI THEATER) and the others (incl the much used ATI NXT2004/2003).

Thomson, Zarlink, Micronas, Zoran, et.al. claim they meet the ATSC A/74 Receiver Guidelines,
but it is unknown if they were incuded in the above tests--probaby not, given the timing.

ATI submitted some (2003/2004) ATSC Decoder test results as part of last year's SHVERA ILLR
proceeding, comparing their latest THEATER chip(s) to unknown "others".

Checkout the 5th Gen Receiver Chip thread for these and other discussions:
http://www.avsforum.com/avs-vb/showthread.php?p=7024579&highlight=test#post7024579

Nitewatchman

05-22-06, 06:31 PM

From April, 2005:
} Generally speaking, leaves will attenuate signals, especially UHF,
} and if they are being blown by the wind, this attenuation is usually
} too variable for the automatic gain control module in your tuner to
} compensate for.

I don't know the "full context" of the above quote, however, I expect "usually" is probably overstating the problem. Not that my results should be considered in any way "typical", however -- For instance, I have 1,000's of mature trees within a short distance of my antenna(some are as close as 20 feet from antenna), and I've never actually experienced the problem when the leaves are ON the trees, no matter how hard the wind is blowing.

However, I have experienced the problem to a certian extent from stations in one market(towers on the same "antenna farm") - specifically only the digital stations in that market operating on channel 50 or above(there are three of them), 12 miles distant+with some "terrain issues" involved --- ONLY when the leaves are OFF the trees and the wind is blowing ... On analog UHF stations from the same market, the "effect" looks very similar to dynamic multipath conditions, with "fluttering ghosts" apparent, and "variable" with the wind gusts ...

As mentioned above, I'm using two different antenna "setups" with seperate feedlines+ an a/b switch before receiver(s) to switch between them. On the "main" antenna setup with rotor(UHF antenna is XG91 at about 37FT above ground), If I rotate the antenna towards the stations in the market with the "wind+tree" problems in the winter months, I never have a problem, including during wind gusts.

However, on the antenna I have side mounted to tower(and aimed towards this market for "convienance" sake so I don't have to use the rotor to receive stations from this market), I had some problems with the wind+tree limbs blowing around as mentioned above. This was solved by #1). a "long-yagi" (31 element UHF yagi+corner reflector, not sure who the manufactuer is, I managed to save it from the dump when I caught my neighbor taking the previous owners antennas down), AND #2). by mounting it 28 feet above ground ... Not 20 feet, not 22 feet, not 25 feet, not 26 feet, not 18 feet, but 28 feet, no problems. Luckily, as I couldn't go lower or higher on this "mast", - Some other "spots" worked fine for 1 or two of 3 the stations transmitting on 50,51+58, but the 28FT "mark" was the only spot which works well for all three when the leaves are off and the wind is blowing .... ........ Not a CM4228, and not a Radio shack early 80's model 25 element UHF Yagi+Corner reflector, and not a couple of other antennas I tried, but the 31 Element yagi+corner reflector I saved from the "dump"... "priceless" .....

What was also a bit surprising to me while moving the antenna to try to find that "sweet spot" I was hoping for was the apparent difference in signal levels between the antenna at 25ft vs 28ft. This was perhaps especially evident on a low power analog station on 40 with a transmitting antenna several hundred feet lower than the other stations in the market .... I suspect the terrain issue is perhaps the most "relevant" factor there ....

I didn't see any tests to see how the tuners/demodulators handle this
problem. :-(

I also didn't see anything that appeared to test for tuners/demodulators
ability to deal with transmitter differential gain error. :-(

I'd also like to see detailed field/receiver performance tests on this issue, I suspect it may be just as much of a concern as the "multipath" issues ....

Nitewatchman

05-22-06, 07:18 PM

e. Zenith 2003: Excellent Summary of Commercial Broadcasters On-Air Tests (19 pgs):
http://www.zenith.com/digitalbroadcast/downloads/ATSC%20Field%20Test%20Results.pdf

f. Zenith 2003: ATSC Seminar--See on-air test summary towards end (265 pgs):
http://www.zenith.com/digitalbroadcast/downloads/Seminar%20Slides.pdf
[Everything you ever wanted to know about ATSC, but were afraid to ask....]

I also like this one from Zenith+Gary Sringoli. (26pgs, No slides, but detailed info on the on-air tests+info on ATSC and receiver design considerations), A paper entitled : "DTV Field Test Methodology and Results And Their Effect on VSB Receiver Design", available here :

http://www.zenith.com/digitalbroadcast/downloads/ATSC%20Field%20Tests%20and%20Rx%20Design.pdf

Konrad2

05-22-06, 10:52 PM

>> From April, 2005:
>} Generally speaking, leaves will attenuate signals, especially UHF,
>} and if they are being blown by the wind, this attenuation is usually
>} too variable for the automatic gain control module in your tuner to
>} compensate for.
>
> I don't know the "full context" of the above quote,

This thread, from April, 2005:
http://www.avsforum.com/avs-vb/archive/index.php/t-381623-p-8.html

> On analog UHF stations from the same market, the "effect" looks
> very similar to dynamic multipath conditions, with "fluttering ghosts"
> apparent, and "variable" with the wind gusts ...

I don't recall having ever seen "fluttering ghosts", although it
makes sense, if the variable attenuation affects one path more
than another.

>> I also didn't see anything that appeared to test for tuners/demodulators
>> ability to deal with transmitter differential gain error. :-(
>
> I'd also like to see detailed field/receiver performance tests on this issue,
> I suspect it may be just as much of a concern as the "multipath" issues ....

I wonder if some sort of tilt/equalization could be applied to compensate?
Hard to know what's going on without a spectrum analyser.

holl_ands

05-23-06, 01:25 AM

I also like this one from Zenith+Gary Sringoli. (26pgs, No slides, but detailed info on the on-air tests+info on ATSC and receiver design considerations), A paper entitled : "DTV Field Test Methodology and Results And Their Effect on VSB Receiver Design", available here :

http://www.zenith.com/digitalbroadcast/downloads/ATSC%20Field%20Tests%20and%20Rx%20Design.pdf
The fol. more complete report also addresses tuner design, diversity antennas, VSWR degradation and related issues:
http://www.atsc.org/news_information/papers/2001_8vsb_performance/Performance_Assessment.pdf

holl_ands

05-23-06, 01:28 AM

>>

>> I also didn't see anything that appeared to test for tuners/demodulators
>> ability to deal with transmitter differential gain error. :-(
>
> I'd also like to see detailed field/receiver performance tests on this issue,
> I suspect it may be just as much of a concern as the "multipath" issues ....

I wonder if some sort of tilt/equalization could be applied to compensate?
Hard to know what's going on without a spectrum analyser.

What specifically do you mean by "transmitter differential gain error"?

Konrad2

05-23-06, 03:13 AM

>>>> I also didn't see anything that appeared to test for tuners/demodulators
>>>> ability to deal with transmitter differential gain error. :-(
>>>
>>> I'd also like to see detailed field/receiver performance tests on this issue,
>>> I suspect it may be just as much of a concern as the "multipath" issues ....
>>
>> I wonder if some sort of tilt/equalization could be applied to compensate?
>> Hard to know what's going on without a spectrum analyser.
>
> What specifically do you mean by "transmitter differential gain error"?

See message #2433 in this thread, by Bob Chase of KHWB-TV:
http://www.avsforum.com/avs-vb/showthread.php?p=5964531&&#post5964531

Additional questions at:
http://www.avsforum.com/avs-vb/showthread.php?p=7590513&&#post7590513

Nitewatchman

05-23-06, 12:59 PM

I don't recall having ever seen "fluttering ghosts", although it
makes sense, if the variable attenuation affects one path more
than another.

Perhaps "fluttering ghosts" is not the best term to describe it ... To put it another way, it's very similar to what occurs on NTSC signals when a multipath reflection from a overflying aircraft occurs.

What also may be interesting here is -- when the wind isn't blowing, any ghosts present are mininal, although it is a bit worse when the leaves are off on certian channels. When the leaves are on, I can detect no "ghosting" of any consequence. Also, since what occurs is frequency specific(for instance the "fluttery ghosts" when the wind is blowing+leaves are off are most apparent on analog NTSC signal on ch 45), one especially cannot draw any conclusions given the different "channels" used by the digital stations, not to mention the slightly different transmitting antenna height.

Hard to know what's going on without a spectrum analyser.

Yes, although I expect with a spectrum analyzer it still may be difficult in such cases to sort out exactly what is occuring.

I expect multiple factors may be involved, at least concerning my observations in my particular circumstance. Perhaps the "variable atteunation" when the wind is blowing, "variable" multipath conditions(leaves on trees vs. leaves off trees), and VSWR could be three possible factors involved.

My understanding is that trees(including leaves) are an attenuation factor, moreso the higher the frequency. My experience is(in a heavily forested "local area"), generally, that attenuation does not seem to be overly (again generally) signficant - From what I can tell, perhaps somewhere in the range of 2~4db on higher UHF TV band frequencies when the leaves are ON trees vs. Leaves off. Since it takes as much as 50~55db of attenuation added into feedline(including estimation of 4db loss on Hi-UHF per 100ft of RG6) to lose a signal lock from local DTV stations, the attenuation from leaves/trees certianly doesn't seem significant in my case.

That is main reason why it's a little difficult for me to grasp why a receiver's AGC circuit would necessarily be the, defacto "primary" concern, here, and why I would like to see more info/field tests involving such matters as tree leaves+wind blowing the tree limbs around. I do know I've used 4 different ATSC receivers(DTC-100, Zenith HDV420, Hisense DB2010, ATSC receiver internal to Sony KD34XBR960 HDTV), and I've detected no apparent differences in performance concerning this matter among those 4 receivers. In fact, I've experienced little apparent indication of significant performance differences among those 4 receivers in any case.

My understanding also is that trees do not "cause" multipath. However, I suspect the varying attenuation factors involved(such as leaves on trees vs. leaves off trees on a "seasonal" basis, or when the wind blows the tree limbs around on a more "immediate" basis) can change(perhaps signficantly in some cases) the multipath conditions at a receiving site.

holl_ands

05-23-06, 02:30 PM

Nitewatchman

05-23-06, 02:32 PM

holl_ands

05-23-06, 03:01 PM

please comment on what i'm thinking of buying to get some TV reception...Am behind trees & about 300' above sea level...

Channel Master CM 3671 Deepest Fringe Crossfire Series
Antenna (CM3671) $125

Channel Master CM 9521A Complete Antenna Rotator System with Infra-Red Remote Control (CM9521A) $ about 90

thanks don
If trees are causing signal level fluctuations, I would suggest using a stacked antenna arrangement,
This would tend to have a good signal level on one or the other antenna and coincident dropouts
on both antennas would be much less frequent.

A conventional RF Combiner would experience a 4 dB insertion loss whenever one of the antennas suffered
a signal loss....so I would also recommend the low loss (0.2 dB) Lindsay Coupler (about $100 delivered).

Although the Crossfire is probably a good VHF antenna, the UHF gain is several dB lower than the CM-4228 or 91XG.
The 8-Bay CM-4228 has useful gain for the upper VHF channels CH7-13 and less so for CH2-6.

I believe that the CM-4228 will also provide better protection against signals coming and going
between the trees, since it has eight distributed active elements vs the one on most other antennas.
So even if you aren't ready to launch a stacked antenna system, you might want to start with just a single CM-4228.

Hence the old adage still applies: separate VHF and UHF-only antennas are preferred.

So I would recommend starting with a $50 CM-4228.
Depending on how that works, you may need to add a second CM-4228
and a $100 Lindsay Coupler.
If the CM-4228 isn't doing the job for VHF, you could add a VHF-only antena.

It would help if you provided your zipcode and location to nearest cross streets.

Nitewatchman

05-23-06, 03:42 PM

The fol. more complete report also addresses tuner design, diversity antennas, VSWR degradation and related issues:
http://www.atsc.org/news_informatio..._Assessment.pdf

Yes, However, That report is not as complete as the report at link I provided concerning the field tests it covers, or the methodology used. Note that I also specifically mentioned the report at link I provided as it was directly relevant to the links I quoted from your previous post concerning the links(slides/etc) from Zenith site.

If trees are causing signal level fluctuations, I would suggest using a stacked antenna arrangement, This would tend to have a good signal level on one or the other antenna and coincident dropouts on both antennas would be much less frequent.

With all due respect, unless you are aware of info from this poster which I am not(especially as this is his first post here on AVSforum), or more specific info relating to his location, I do believe you may be putting the cart before the horse, here. He said he has trees, he didn't say whether or not he has any reception related difficulties due to those trees, nor does the fact he has trees suggest he will necessarily experience such difficulties.

[update] - Yes, I realize you said "if". One question concerning the above. I'm curious how much experience you've had with stacking broadband antennas for TV reception, and in how many cases you've seen concerning "trees causing signal fluctuations" with vertical and/or horizontal stack vs. a "well placed" single antenna, or in how many circumstances you've seen that the stack was required?

Although the Crossfire is probably a good VHF antenna, the UHF gain is several dB lower than the CM-4228 or 91XG. The 8-Bay CM-4228 has useful gain for the upper VHF channels CH7-13 and less so for CH2-6.

I'm curious, what info are you using to detirmine "several db" of additional gain on certian frequencies is going to be useful, or necessary in this case ?

While it is true CM4228 offers useful VHF gain on channel 7-13, its directivity on VHF is another matter.

Hence the old adage still applies: separate VHF and UHF-only antennas are preferred.

What is "preferred" depends upon circumstances. For instance, many folks are likely looking for a single antenna solution, perhaps rather than some of the more complicated possible solutions as detailed in your post - also keep in mind more mast space is required for multiple antennas.

CM3671 is among the best, hi-gain single antenna(Broadband VHF+UHF) solutions I know of [update], including in terms of gain on UHF, and directivity wise.

update: Oh, especially if this is fringe reception we are discussing, a preamp may be benefical for him as well.

Nitewatchman

05-23-06, 05:24 PM

> do you see any interference/intermod effects from the local Toledo stations?

What does intermod look like? Is there an example online?

Having some extra time, I thought I might provide some comments on the above, as If I recall correctly, I don't believe anyone has commented on it so far.

While I haven't done the "math" nor can I say with 100% certianity that intermodulation distortion is the "direct cause"(although appropriately tuned notch filters for the "on-channel" signal certianly do get "rid of" these issues) -- I can *sometimes* spot what I'll call "tuner or preamp overload" problems from such evidence as :

Signs of Signals from NTSC analog stations "showing up" on frequencies where they shouldn't be -- such as say, channel 2 showing up to some extent on UHF 60, or Portions of "ugly" video transmitted on VHF channel 7(or even "mixtures" of video/audio signals from different stations) "showing up" on cable channel 22(obviously setting the TV to use cable channels with the antenna) ... Using a TV which doesn't "mute" the screen when interference laden or "weak" signals are present can be beneifical for this, as in my case is one particular set I have(samsung TXN2668) that allows you to turn off AFT and tune "manually"(it even lets you "save" your manual tuning setting per channel), and it also has an additional LNA "inside" the TV which can be turned off/on selectively by channel. An "old" TV with mechanical tuners+"manual" tuning may be somewhat beneficial here as well.

BTW, you can also sometimes spot this problem with FM carriers(which could be from other sources besides FM broadcast -- such as the audio carrier from a NTSC TV station, or other narrowband FM signals), FM interference appearing generally as diagonal "lines" on an NTSC video signal ...

With digital - I expect in most cases using such methods as the above to spot such problems would probably be pretty much impossible -- Although, I have noticed it is sometimes possible to recognize a on channel 8VSB signal with a analog NTSC receiver via the appearance of such "indicators" as "big, Horizontal snow", depending upon such factors as the TV's AFT, and/or how you have "manual tuning" adjusted, if any such option is available.

Attached is a set of screenshots providing an example of 8VSB signals as "detected" on an NTSC tuner. These were taken with digital camera of the "snow" that resulted on certian channels via one particular RCA TV I used to have whose AFT "found" these when tuning to a channel with a ATSC signal. In the case of the AFT for this TV, it would only "work", for example, if there wasn't an upper adjacent channel DTV signal present. At Top left is evidence of a particularly strong on Channel ATSC signal, Top right is a somewhat weaker on channel ATSC signal, Bottom left is a on-channel ATSC signal just a few DB above threshold(with a ATSC receiver, of course), Bottom right is of a channel with no detectable "signal" present. (Note: the "horizontal" darker areas I believe are due to camera's shutter speed) ...

tv4u

05-25-06, 01:13 PM

I need some help with selecting an antenna or antennas.

To keep from starting a new thread I just joined in on this one since it is the closest that I could find. I am from Houston, MS 38851.

I have a Hitachi 57S700 TV and I am wanting to receive the HD and analog broadcasts in my area.

Here is my broadcast information:
Station--VHF/UHF/DTV--Orientation in degrees--miles -- Channel -- Frequency
CBS-----DTV-----122-----15.5-----4.1----35
CBS-----VHF-----122-----15.5------4------4
FOX-----DTV-----169-------5.5-----27-----27
FOX-----UHF-----169-------5.5-----27.1--16
NBC-----VHF-----169-------5.5------9------9
ABC-----UHF-----169-------5.5-----45----45

Would like to get this one too but not near as important
PBS-----VHF-----184-----36.1-------2------2

I would also like to use this to pick up FM radio stations. Most radio stations are 45 plus miles away.

Do I need one antenna or more than one?
Which antenna do you suggest for my situation?
Will I need a rotor?
My wife would rather have an attic mount but would probly go along with the antenna outside if I can keep it where it is not so obvious from the road. Like maybe on the southwest corner of our house.

Here is what I am wanting to wire this I have 6 locations that need to receive the antenna signal and I have Direct TV that I need to run to one receiver in the living room.

I have a distribution box in my attic toward the north end of my house, the dish is on the north end but the antenna needs to be on the south end where the television station transmitters will be in line of sight.

Therefore I am looking a about a 60' run fo cable from the antenna to the distribution location. From there all the runs should be less than 100' except for maybe 2, they may run just a little over.

Can I do an attic mount or do I need an outside mount?
Do I just split the signal in the attic withe splitters or do I need a distribution amp?
Do I need pre-amp and amps.
Do I need a direct run from the antenna to the living room which closer to the south end of the house where the antenna will be if I do an outside mount?

I am lost please help, ask any questions that I may not have answered.

Thanks

Konrad2

05-25-06, 05:16 PM

> CBS-----DTV-----122-----15.5-----4.1----35
> CBS-----VHF-----122-----15.5------4------4

I assume this is the same station. Do you know which frequency
the digital broadcast will be on after the analog goes away?
If the digital will stay on channel 34, consider getting a good
UHF-only antenna for this, and try rabbit ears tuned for channel 4.
If the digital will move to channel 4 I'd go the other way around
and look at getting a good VHF antenna for it, possibly a single
channel model if you don't expect additional stations in that
direction. Remember that the analog broadcasts are scheduled
to go away in a couple years.

You can probably get the 169 and 184 stations with a single antenna.

> Will I need a rotor?

Personally I'd avoid a rotor since it can only point in one direction
at a time. If two people want to watch shows in different directions
you have a problem. And getting a VCR/DVR to control a rotor would be a
hassle. Instead I'd try one antenna for CBS and one for all the others.
You can insert the CBS channel(s) into the main feed with something
like a CM Join-tenna, although I'd try and find a shielded version.
Or you can have two coax runs and a switchbox. But this could be a
hassle with 6 locations, and again you have the DVR control problem.

> Can I do an attic mount or do I need an outside mount?

You don't say how much room there is in your attic, or what type of
material the antennas will be looking through. If you have a metal
roof and aluminum siding, or dense materials like stone/brick/slate,
good luck. If there is plenty of room, and little or no metal, give
it a try. If it works in the attic you don't have to worry about
wind, corrosion, etc.

> Do I need pre-amp and amps.

Try it without an amp first. If you get significant snow on analog
channels an amp will probably help. Some of your stations are close
enough to worry about overloading the amp. A preamp will have less
noise than a dist amp, and will probably have a switchable FM trap,
which you might need. A dist amp is less likely to overload. I'd
try a low gain Winegard preamp with FM trap.

> I would also like to use this to pick up FM radio stations. Most
> radio stations are 45 plus miles away.

If you have any nearby FM stations, you might need to keep the FM and TV
separate. Keeping the non-TV stuff out can be as important as getting
the TV stuff in.

tv4u

05-25-06, 06:44 PM

" CBS-----DTV-----122-----15.5-----4.1----35
CBS-----VHF-----122-----15.5------4------4

I assume this is the same station. Do you know which frequency
the digital broadcast will be on after the analog goes away?"

Yes this is the same station and no I don't know which frequency they will keep using.

" You can probably get the 169 and 184 stations with a single antenna."

Which antenna do you suggest I have one now from radio shack which is mounted in the attic it is about 80 inches long and it does pretty good but 45 is not coming in worth anything and it is on the same transmiiter as channel 9 which comes in real good. I called the station and they said that 45 is on low power right now for some reason.

"Instead I'd try one antenna for CBS and one for all the others.
You can insert the CBS channel(s) into the main feed with something
like a CM Join-tenna, although I'd try and find a shielded version."

Again which atenna or antennas do you suggest? Explain a little more about the Join-tenna I have never heard of that, don't have a clue. How would you wire for it.

"You don't say how much room there is in your attic, or what type of
material the antennas will be looking through"

I have a pretty good bit of room in there althouth there is bracing every so for apart. I have a 80 inch length antenna in there now and could probably not go any larger. The roof is plywood with fiberglass shingles the wall all the way up on the side of the house where the antenna has to aim is brick.

"I'd try a low gain Winegard preamp with FM trap."

Again this is something I know nothing about. Do you have a link for me?

"If you have any nearby FM stations, you might need to keep the FM and TV
separate."

I should have said all FM stations are 40 miles or more from me.

What about the length of cable run?

I have 2 antennas one is the Radio Shack that I mentioned earlier which I am currently using and the other is a Channel Master CM 4228 8-Bay Bowtie UHF Antenna. Is there a way to combine these two antennas for me to get the maximum performance that I am looking for or do I need to start all over or what.

Thank you for your respons. Anyone else is also welcome to join in.

thanks
tv4u

Konrad2

05-26-06, 12:53 AM

>> " You can probably get the 169 and 184 stations with a single antenna."
>
> Which antenna do you suggest I have one now from radio shack which is
> mounted in the attic it is about 80 inches long and it does pretty good
> but 45 is not coming in worth anything and it is on the same transmiiter
> as channel 9 which comes in real good. I called the station and they said
> that 45 is on low power right now for some reason.
...
> the other is a Channel Master CM 4228 8-Bay Bowtie UHF Antenna.

Have you tried to get channel 45 using the CM 4228?
The CM4228 has a pretty good reputation and is considered by many as one
of the best UHF antennas available. (I haven't tried it myself.)

Most Radio Shack products do not enjoy a good reputation.

You might try:

Point Radio Shack antenna at CBS. I'm assuming RS antenna is
a VHF/UHF combo.

Point CM 4228 at Fox/NBC/ABC. The CM4228 has some gain
at channel 9, you might get lucky. See graph at bottom of

http://www.hdtvprimer.com/ANTENNAS/comparing.html

Although according to the graph, the gain varies by about 5 dB
across the channel, which might cause problems?

Try rabbit ears tuned for channel 2. If that doesn't work
well enough, or if CM4228 can't get chan 9, get a good VHF
antenna for 2 and 9.

A good antenna for channel 2 will be large, due to the wavelength. You might
want to find out if that station will remain on channel 2 after the analog
shutoff. If it will move to VHF-HI (chan 7-13) you could get a VHF-HI antenna
that will be smaller than one that does all of 2-13. If it will move to UHF
you should be able to get it with the CM4228.

> The roof is plywood with fiberglass shingles the wall all the way up on the
> side of the house where the antenna has to aim is brick.

I'd guess you have a good chance going through plywood with fiberglass shingles.
If the antenna has to "look" through brick (e.g. a gable) there will be a lot
of attenuation, especially for UHF.

> Explain a little more about the Join-tenna I have never heard of that, don't
> have a clue. How would you wire for it.

The idea is you have a band-reject filter in the main feed at the frequency
of the station on the aux antenna. You also use a band-pass filter on the aux
antenna. Then you can combine the signals together without getting multipath.
In your case you have two chanels on the aux antenna, so you'd first run the aux
antenna through a 2-way splitter, and then use 2 join-tennas, one for chan 4 and
one for chan 35.

http://www.hdtvprimer.com/ANTENNAS/GlossaryG.html#jointenna

I've seen a nice wiring diagram explaining the jointenna, possibly earlier in
this thread. Try the forum's thread search. If not, perhaps google can find it.

See also: Pico-Macom SC-4, MX4U, MX7
http://www.picomacom.com/macom/products/catalog-C1.htm

Winegard VF-4000
http://www.winegard.com/offair/trapsfilters.htm

Tin Lee
http://www.tinlee.com/

> What about the length of cable run?

Might hurt things slightly if you keep the antennas in the attic and don't use an amp.
If you go with an amp or put the antennas outdoors or both, the cable length should be
fine. I would worry more about the quality and condition of the cable than the length.
Weather/sunlight/water/critters take their toll on cable that is outdoors. I suggest
RG6-quad-shield. If you want to avoid an amp, RG11-quad-shield will have slightly less
loss, but probably isn't worth the hassle and expense. You can get RG6QS with factory
attached connectors at Lowes. The "quad-shield" will help keep bad stuff out. Shielding
is your friend.

>> "I'd try a low gain Winegard preamp with FM trap."
>
> Again this is something I know nothing about. Do you have a link for me?

http://www.winegard.com/
http://www.winegard.com/manuals.htm
http://www.solidsignal.com/manu_display.asp?main_cat=03&manu=Winegard

http://www.winegard.com/offair/separatorsjoiners.htm
http://www.blondertongue.com/
http://www.channelmaster.com/
http://www.antennacraft.net/
http://www.picomacom.com/
http://www.mpja.com/
http://www.warrenelectronics.com/
http://www.warrenelectronics.com/Antennas/joiners.htm
http://www.warrenelectronics.com/Antennas/Att1.htm
http://www.summitsource.com/
http://www.summitsource.com/antennas-accessories-filters-and-traps-c-47_48.html
http://www.weisd.com/
http://www.weisd.com/store2/1290LIST.html
http://www.solidsignal.com/
http://www.starkelectronic.com/

holl_ands

05-26-06, 01:27 AM

Second Channel Election Results:

WLOV-DT 27.1 (FOX) elected to stay on CH16
WCBI-DT 4.1 (CBS) elected to stay on CH35
WKDH-DT 45.1 (ABC) elected to stay on CH45

WTVA-DT 9.1 (NBC) elected to CHANGE from CH57 back to VHF CH9 (deadline is Feb 2009)
However, due to excessive interference, this has not been approved by the FCC
and may result in some other channel election:
http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-06-991A1.pdf

WMAB-DT 2.1 (PBS) will remain on VHF CH10 (Miss. State, 184 deg, 35.9 miles, low power 4.3 kW)

First four are "yellow" antenna recommendations per antennaweb.org,
whereas (thus far) low-power PBS is "purple" .
If they raise the power, it could become much easier to receive....

So it looks like you may need both VHF and UHF antennas.
And except for low power PBS, you're in the strong signal strength region.

The narrow beamwidth of your current antennas can not even begin to cover the 47 degrees of separation without a rotator.

Most any inexpensive, non-amplified, widebeamwidth antenna should do the UHF job,
such as the Terk HDTVi (with VHF Rabbit Ears), Loop/Rabbit Ears, Silver Sensor (plus VHF Rabbit Ears),
or if you like, the widebeamwidth CM-4221 4-Bay. Probably doesn't even need to be in the attic.

Although it is possible that you are "below" the main transmit antenna beams,
you could also be picking up strong reflections from a few miles away.....
Which is why you should try pointing the antenna in all directions to find the "sweet spots".
Nulling out reflections from one direction may be the antenna's primary function, rather than simply pointing toward the towers.

Since you are only 5.5 miles away from high power towers, you need to be very, very careful not to overload your system.
You may be experiencing overload with your current high-gain antenna arrangement....
Although the loss through cable downlead and RF Splitters could help.

holl_ands

05-26-06, 02:03 AM

You should check your local thread:
http://www.avsforum.com/avs-vb/showthread.php?p=7570171&highlight=wkdh#post7570171

WKDH on CH45 (ABC) reportedly has not yet changed over from analog to digital....still waiting on FCC approval...

It also looks like WMAA on CH43 (PBS?) in nearby Columbus is also converting from analog to digital....timeframe unknown:
http://radiostationworld.com/locations/United_States_of_America/Mississippi/tv.asp?m=col

AntAltMike

05-26-06, 02:45 AM

Pico's MX4U, a tunable, 4-input UHF bandpass filter/combiner, has been out of production for about a decade and is nearly impossible to find. Its case shielding is not tight, and so it doesn't work well when the signal strength differential between essential channels is great.

Their tunable BPF-UHF, which was an excellent product, is also out of production.

Nitewatchman

05-26-06, 02:00 PM

Which antenna do you suggest I have one now from radio shack which is mounted in the attic it is about 80 inches long and it does pretty good but 45 is not coming in worth anything and it is on the same transmiiter as channel 9 which comes in real good. I called the station and they said that 45 is on low power right now for some reason....

Thank you for your respons. Anyone else is also welcome to join in.

Assuming that is probably a RS VU-90 XR VHF/UHF combo antenna ( see here : http://www.radioshack.com/product/index.jsp?productId=2103085&cp=2032057.2032187.2032189.2032205&parentPage=family or here : http://www.hdtvprimer.com/ANTENNAS/VU-90XR.html ), I'd probably start with moving it outside, perhaps on a "temporary/testing" basis and see what you get with it with a little "manual rotation" to perhaps get a better idea concerning whether or not a rotor or other options may be desired, or required. You might want to start with it aimed "roughly" SE or SSE and see what happens before trying more precise aiming for your various stations in different directions. If desired, You might want to try the same with the CM4228 while you are at it to "see what you get", perhaps especially(if necessary) concerning your reception of the station on 45.

If some of the signals are "too strong", adding attentional attenuation in feedline(such as splitters or attenuators - there is a max -20db variable attenuator available at Radio shack) should be benefical(at least where the stronger signals are concerned), and also perhaps give you a bit of an idea concerning what you'll be able to get away with concerning your plan for distributing feed from antenna to 6 different spots receviers .... Each 2 way splitter is about 3.5db of loss, 100FT RG6 is about 4db loss per 100FT on UHF.

-------------------------

As Holl_ands mentioned, I'd also recommend checking out your local thread, as you can probably find reports and suggestions there from others in your area which may be useful, concerning their reception+what equipment they are using for their antenna setup.

holl_ands

05-26-06, 07:54 PM

Your antennaweb.org results summary:

ANTENNA/CALL/VIRTUAL/NTWK/DEG/MILES/REAL CHAN
yellow-uhf WLOV 27 FOX 169° 5.5 27
* yellow-uhf WLOV-DT 27.1 FOX 169° 5.5 16 [DTV Channel Election]
yellow-uhf WKDH 45 ABC 169° 5.5 45
* yellow-uhf WKDH-DT 45 ABC 169° 5.5 45 TBD [DTV changeover "soon"??]
yellow-vhf WTVA 9 NBC 169° 5.5 9 [DTV Channel Election Denied]
[WTVA-DT refiled for CH8 in recent Third Round]
* yellow-uhf WTVA-DT 57 NBC 169° 5.5 57 FCC Ext

* yellow-uhf WCBI-DT 4.1 CBS 122° 15.5 35 [DTV Channel Election]
yellow-vhf WCBI 4 CBS 122° 15.5 4

blue-uhf WMAV 18 PBS 310° 44.9 18

blue-vhf WMAB 2 PBS 184° 36.1 2
* violet-vhf WMAB-DT 2.1 PBS 184° 36.0 10 [DTV Channel Election]

violet-uhf W30BY 30 TBN 260° 41.6 30

violet-vhf WMAE 12 PBS 20° 58.4 12
violet-vhf WHBQ 13 FOX 335° 99.3 13
violet-vhf WABG 6 ABC 247° 89.6 6

[I deleted some unlikely results....such as UHF at 80+ miles.....really????]

===========================================
The above HDTVPrimer link only provides the antenna pattern for the VHF part of the R-S VU-90XR.
Note the very wide beamwidth for the lower VHF channels (CH2-6),
and very wide beamwidth (about 30 degrees) for upper VHF channels (CH7-13).
Also note the typical sidelobe nulls at about +/- 30 degrees.
So as long as it's pointed generally South to SE, it should readily pick up CH 2 (PBS), 4 (CBS), 9 (NBC) and 10 (PBS-DT).
Although CH12 (PBS) would be on the backside of the antenna, it still might surprise you with an appearance--but don't count on it.

============================================
Now let's consider how well the current antenna is performing for UHF (at least in theory)....

The VU-90XR appears to be similiar if not the same as the CM3016,
the front UHF section of which appears closest to the CM4308 Corner Yagi--which has a +/- 3 dB
beamwidth of 56 degrees for CH14, decreasing to only 31 degrees for CH60.
http://www.starkelectronic.com/cmg5.htm
http://www.starkelectronic.com/cmg4.htm

So if you pointed it towards 145 degrees (half-way between 169 degrees and 122 degrees),
CH57 would be about 24 degrees away from the beam max.
However this is close to the typical sidelobe nulls (see CM4018 antenna pattern plot at +/- 30 degrees).

So to bring CH57 out of the sidelobe null, you would need to slightly reorient the antenna to
about 154 degrees, leaving Columbus stations in the other sidelobe null....letting in mostly mutipath...

So it appears that you need something.....different....
Since the beamwidth of the CM4228 is even narrower, viable alternatives would include
either one of the wider beamwidth antennas I mentioned above...or a dual antenna arrangement.

holl_ands

05-26-06, 08:31 PM

Dual antenna arrangements can be tricky, so determine how each antenna performs alone
and then see if you lose any stations when you combine them.

Of course, you might want to mount one of the antennas on a rotator with a separate downlead
to the "primary" HDTV and let the other antenna feed the existing house system.
If you have room, you might be able to use the CM-4228 with a rotator in the attic, rather than on the roof.

You can start with the R-S VHF/UHF Combo pointed towards about 175 degrees (half-way between 169 and 184 degrees).
This results in your best VHF antenna being used for the more "distant" CH2 and CH10.

The CM-4228 can then be pointed towards 122 degrees to pick up digital CBS on 4.1 (CH35) and probably/possiby analog CBS on CH4.

There are lots of ways to combine two antenna systems....
You could start with an RF Splitter ("reversed" with antennas on two OUT ports and IN port connected to downlead).

Can we presume that the R-S Combo picks up CH4 just fine and thus the CM-4228 is only needed to add digital CBS?
A better way to add one and only one channel is to use a JoinTennna:
http://www.warrenelectronics.com/Antennas/joiners.htm

A JoinTenna is special order for a particular channel (e.g. CH35). One of the ports passes ONLY that channel to the downlead,
whereas the other port passes ALL channels EXCEPT that channel to the downlead....give or take some adjacent channels....
This minimizes the multipath injected from one antenna's signals into the other.
Whether you need the JoinTenna won't become obvious until you do some comparisons with and without both antennas combined.

Nitewatchman

05-26-06, 09:39 PM

I stand by my previous suggestions. In summary --- Try the antenna(s - one at a time) you have first, outdoors on a "temporary/testing" basis, with "manual" rotation(as necessary), if for no other reason to get a better idea of what you have to work with, and what you may want to think about trying, next.

You would really probably need a on-site test by a pro-antenna installer for more realistic and "scientific" recommendations than it is likely any of us will be able to provide here.

Although CH12 (PBS) would be on the backside of the antenna, it still might surprise you with an appearance--but don't count on it.

I believe he said that station might not be of uptmost importantce to him, in any case, I do agree a rotor will probably end up being beneficial for him ..

Hence one of the reasons why I suggested he try his existing antenna outdoors, and with "manual rotation" first, to see what sorts of results he achieves with his current antenna(s) before thinking too much about other possible solutions, and what he may want to do. I only suggested the SE direction first as a place to start.

Personally, at this point, FWIW I probably wouldn't mess around too much with Jointennas and the like before analog shut off, or at least until the DTV table of allotments are "set in stone" for post-transistion. But, that's just me.

Unfortunetly, I don't think there is any implementation of CEA-909 "smartenna" interface and appropriate antenna/receivers which would necessarily work well for him given multiple sets/receivers/etc, otherwise, such a solution as you've tried with the "smartenna" and the Sylvania/funai STB which supports it would seem to me to perhaps be an "optimal"(although expensive) solution in this case ... Although, such a solution still may be a good one for a "primary" set, with, along the lines of something you've just mentioned in last post, another antenna used for the other sets ....

Now let's consider how well the current antenna is performing for UHF (at least in theory)....

In practice, I suspect the difference between the antenna's "real world" performance for reception from the stations desired in the attic(as is the current case), and mounted outdoors will probably likely be substantial.

The VU-90XR appears to be similiar if not the same as the CM3016,

Its similar in appearance, but, unless something has changed, I do not believe it is "the same". You could probably just as well pull up the specs for the Winegard PR7010(available in PDF format from winegard site) and base your predictions on likely somewhat similar, but also equally (somewhat)incorrect info.

So it appears that you need something.....different....

I think Appearances can sometimes be "deceiving" concerning real world performance vs. our expectations based on "theory" ....

Since the beamwidth of the CM4228 is even narrower, viable alternatives would include either one of the wider beamwidth antennas I mentioned above...or a dual antenna arrangement.

I expect a CM4221 may especially be a good choice for UHF in his circumstance, perhaps he could use it for UHF, and use the VU90 only for VHF(or another relatively "small" VHF broadband antenna). Since I believe he indicated he was interested in analog reception as well, I'm doubtful he will acheive an acceptable quality signal for his low-VHF analog with any UHF antenna .... Although, he would still need to use a rotor for optimal reception of all "possible" stations with that setup, just perhaps not quite as often as would be the case with a antenna with a much narrower beamwidth such as CM4228 or XG91 ...

Since it seems I wasn't able to get my "point" on this through the first time .... I'll repeat it again .... Again, my point was, if it were me, I would "see what happens" with his existing antenna(s) first to try to get a better idea of what I might be able to "get away" with - as I noted, on a "temporary/testing" basis and mounted outdoors, before spending more $ and time/effort exploring other options ..... I also expect he will have the oppurtunity to learn quite a bit more about the actual "reception conditions", and what he might need/want to do vs. anything any of us might "predict" concerning his reception, here.

So if you pointed it towards 145 degrees (half-way between 169 degrees and 122 degrees), CH57 would be about 24 degrees away from the beam max.
However this is close to the typical sidelobe nulls (see CM4018 antenna pattern plot at +/- 30 degrees). So to bring CH57 out of the sidelobe null, you would need to slightly reorient the antenna to about 154 degrees, leaving Columbus stations in the other sidelobe null....letting in mostly mutipath...

Interesting how I can receive stations almost continuously, without dropouts(except over a few degrees or so where the sidelobe nulls are deepest) via an XG91 WHILE I'm rotating the antenna - 360 degrees all around(4th generation Zenith chipset), and there are *no* dropouts while I'm doing this up until 110 degrees "off target", meaning, including any nulls in the pattern between 0~110 degrees "off target" .... Of course, the wind isn't blowing the trees around currently, either ;)

Interesting that I've heard reception reports from folks using VU90 and "similar" in similar situations as TV4u who receive excellent dropout free reception from all desired stations .....(well, not counting the stations of interest off the "back side") ....

NOW DON'T take that the wrong way. While I agree what you say here makes perfect sense, even if it isn't necessarily based on 100% accurate info on the VU90. HOWEVER, believe it or not, these things can, sometimes turn out better than what you may think .....

Oh, well. At least we don't have to "worry" about you recommending he use an antenna with "spilateral" technology ... (yes, I read OpenDTV as well, and yes, that is a joke) ... ;)

Of course, you might want to mount one of the antennas on a rotator with a separate downlead to the "primary" HDTV and let the other antenna feed the existing house system.

That, and much of your last post is very much along the lines, or "similar lines" of what I might be thinking about, depending upon how the "test" turns out with the current antenna outdoors+with manual rotation to see what all can be received, to see what extent other options for improvment(such as adding a rotor/multiple antennas/jointennas/etc) might be desired ... If he is going to DIY, what is desired+what is acceptable compromise is really something *he* probably has to work on and decide about, I think ....

holl_ands

05-26-06, 10:23 PM

The current Smart Antenna solution can not be shared with multiple receivers and must be used with the Sylvania 6900DTE OTA STB.
Hence I didn't bring it up....

After my first quick post primarily addressing channel election results,
I took the time to figure out what might be possible with the current antenna system.
It's always best to assess whether the current installation can be made to work,
rather than immediately going through the arduous process of removing from the attic
and setting up outdoors.

The antennas I cited are (almost?) idential in construction and it is well known
Channel Master manufactured several of R-S antennas.
The PR7010 is a significantly different design--and has significantly different antenna patterns.

Using R-S for VHF only and CM-4221 for UHF only should also be a viable Dual Antenna alternative.
However, it may be somewhat more susceptibe to multipath than using
a Jointenna with his current R-S and CM-4228 antennas.

Each approach has various pros and cons...

holl_ands

05-27-06, 01:18 AM

FYI: WTVA-DT refiled for CH8 in the just completed Third Round of DTV Elections.
Subject to FCC approval, of course...

I updated above list to reflect this info.

I also see from the FCC database that WMAA on CH43 (changing "sometime" to digital WMAA-DT)
only applied for 81 kW and their antenna has a 14.5 dB null in your direction.
Even so, with it being only 15.5 miles away, at some point it may become a viable PBS-DT option.

Nitewatchman

05-27-06, 02:16 AM

Going to try this one more time, after this, I'm going to give up and go back to lurking on this thread ...

The current Smart Antenna solution can not be shared with multiple receivers and must be used with the Sylvania 6900DTE OTA STB.
Hence I didn't bring it up....

Yes, and as I indicated in last post I am aware of that. You did, however bring up the possibility of using a seperate antenna for the "primary" HDTV .... Hence, I mentioned it as, it would seem to be a good solution to me in this case from a purely "reception based" standpoint, such as for solely the "primary HDTV" ....

It's always best to assess whether the current installation can be made to work,
rather than immediately going through the arduous process of removing from the attic and setting up outdoors.

I don't believe there is *Any way*, in this particular case your *assessment* can definitively say the poster absolutely WILL NOT be able to acheive satisfactory results with the VU90 mounted outdoors with one heading used for the stations located at 122+169 degrees, or the stations at 169+184 degrees.

Concerning the "possibility" of this working as an acceptable compromise", another way I might say it might be something such as, "it probably isn't likely, and, for the UHF stations in this situation, you might be best off trying an antenna such as CM4221 -- however, my experience, and the reports of success from others in some cases in similar circumstances, and the fact that you have a VU90 on hand to try it also tells me it also may be worth a shot to try it ....."

In my case, I would not consider the process I suggested to be arduous. I suppose it's somewhat a matter of opinion, although don't assume others opinions on this are necessarily the same as yours.

Also, Personally, in addition to assesing the situation "theoretically" to some degree, I would also tend to want to see direct observation/experimentation concerning what happens with the antennas on hand(and outdoors) to gain a better understanding of the "real world" situation before spending more $, time and effort, on more antennas or rotors or jointennas, and also to have better, real world, direct evidence at hand to be able to better make decisions concerning what I might try to improve things, or concerning the compromises that may be involved.

Hence that is MY suggestion, FWIW, and there is nothing wrong with it. The poster asking the questions can take it or leave it.

The antennas I cited are (almost?) idential in construction and it is well known that Channel Master has manufacturered several of R-S antennas.

I hadn't heard that. Could you provide a link with evidence on this? Thanks. In the past, I've often heard it was antennacraft which used to supply the antennas to Radio shack(don't know about presently), I do not know about the "advantage" series of CM antennas.

The PR7010 is a significantly different design--and has significantly different antenna patterns.

Signficantly different Yes, but also "somewhat similiar" concerning overall performance and general antenna "type"(it's a mid-size VHF/UHF combo antenna with similar gain - and Beamwidth at 1/2 power points generally in the 30~40 degree range on mid~hI UHF according to the specs) ... Let's look at some pictures.

CM3016 :

http://www.channelmaster.com/images/3016.jpg

RS VU90XR :

http://www.radioshack.com/product/index.jsp?productId=2103085&cp=2032057.2032187.2032189.2032205&parentPage=family

As you said, very similar in construction and design. The pics are very little to "go on", and the pic on the RS site isn't a photograph ... however, if you notice, it seems apparent the "middle" two VHF elements on CM3016 are of more similar length than the RS VU90 graphic, which indicates the rear two VHF elements are instead, of more "similar" length. Also, on the VU90, two of the UHF corner reflector elements appear to be considerably longer, whearas they appear to be of similar length in the CM3016 pic .... There are also apparently 4 elements on each of the bottom+top reflectors on VU90, looks like only 3 each in the pic of CM3016 .... Hard to tell, but it looks like driven element on UHF section is closer to the first director element on the CM3016 ....

My point here is, I don't think we know enough at this point to "mix and match" unknown(theoretical) "specs" for VU90 with CM3016 or CM4308 as if they were the *same* antenna. Maybe they are, but where's the evidence that proves it?

Never mind, as it really doesn't matter anyway, as the CM3016 *may* "work" in this circumstance to some desireable extent(including on UHF) as might the VU90 .... And, they *may* not as well ...

Using R-S for VHF only and CM-4221 for UHF only should also be a viable Dual Antenna alternative.
However, it may be somewhat more susceptibe to multipath than a using a Jointenna with his current R-S and CM-4228 antennas.

Each approach has various pros and cons...

I agree with you, here -- however, VU90, perhaps with rotor is also a viable, "one size fits all" option as well, and who knows, It might even be preferred if only "one antenna" could be installed outdoors, and I doubt a CM4228 will perform as well on UHF indoors as the VU90 outdoors ..... Just depends on what the poster "wants", as I said *he* is the one that has to decide that, we can only offer suggestions in hopes it might help him out ....

And What? That's the best "assesment" you can "work out" ? ..."pros and cons" and "may be somewhat more susceptable to multipath?" Sounds like to me you're saying he'll need to "Try it" and see what is best "pro and con" wise.... Gee, sounds a lot like the same thing *I* am saying, imagine that .... ;)

And BTW, I don't believe 80 mile "fringe" local reception on UHF is necessarily all that uncommon in The "Flat lands" of Texas, MS, La+Great plains states. I Also don't know if I'd "personally" consider ~4KW ERP for digital on VHF "low power", although, I suppose most posters on this forum might, and it is certianly 6~9db less than the more typical VHF-HI digital operation, which generally seems to be in 16~30KW ERP range. According to current FCC rules, Low power/class A digital stations on VHF (channel 2-13) are limited to 300Watts ERP .....

miked2023

05-28-06, 02:28 PM

Hey guys, Noob here so I apologize in advance - Got Direct TV HD DVR(with their antenna) yesterday - the local HD channels are either breaking up or in the case of ABC not working at all. After doing further research at antenna.org I realised that I'm 22 miles away from the transmitter - I assume this is the reason why. Can anything be done? Like a booster or something? Will the new Direct TV DVR that's supposed to come out address this problem? thanks.

Rammitinski

05-28-06, 04:47 PM

miked2023

05-28-06, 05:10 PM

The one that comes with direct TV - I was trying to find a link but no go. I just realised though I get the HD feed on channels 86, 83, etc - so I think I'm all good, no? I'm a little confused what the difference is between these direct TV feeds )86, 87, etc) vs. picking it up off the antenna. thanks and sorry if this is the wrong forum.

mrtbig

05-28-06, 05:18 PM

Can someone answer this dish question?

I know I need at least the 3 LNB dish for HD, but will the newer ATR dish for MPG4 still work the the current HD10-250 and non HD tivo's?? Still want to use antenna for the local HD's.

TotallyPreWired

05-28-06, 05:26 PM

...I just realised though I get the HD feed on channels 86, 83, etc - so I think I'm all good, no? I'm a little confused what the difference is between these direct TV feeds )86, 87, etc) vs. picking it up off the antenna. thanks and sorry if this is the wrong forum.
Well, there is a good chance that you'll be losing the DNS feeds in the future. Also, I don't know where you live, but your locals are almost certainly different stations than the DNS stations.
....jc

TotallyPreWired

05-28-06, 05:28 PM

miked2023

05-28-06, 07:50 PM

Well, there is a good chance that you'll be losing the DNS feeds in the future. Also, I don't know where you live, but your locals are almost certainly different stations than the DNS stations.
....jc

Yes the locals are different (Los Angeles). That sucks I'm going to lose the DNS feeds - are they going to come up with something else to replace? My antenna gets really bad HD reception. Sorry if this is in the wrong section, if so, perhaps someone can point me to the right forum.

TotallyPreWired

05-28-06, 08:05 PM

Yes the locals are different (Los Angeles). That sucks I'm going to lose the DNS feeds - are they going to come up with something else to replace? My antenna gets really bad HD reception. Sorry if this is in the wrong section, if so, perhaps someone can point me to the right forum.
As long as you mention 'Antenna', I think that you're ok. ;) Never-The-Less, are you saying that you are in the LA DMA, or that's where the DNS feeds are from? :confused: W/O your location(Zip Code) it's hard for people in this forum to be of assistance. :eek:
....jc

miked2023

05-28-06, 09:19 PM

As long as you mention 'Antenna', I think that you're ok. ;) Never-The-Less, are you saying that you are in the LA DMA, or that's where the DNS feeds are from? :confused: W/O your location(Zip Code) it's hard for people in this forum to be of assistance. :eek:
....jc

I'm in LA - Sherman Oaks to be exact. Zip 91411. thanks.

TotallyPreWired

05-28-06, 09:47 PM

I'm in LA - Sherman Oaks to be exact. Zip 91411. thanks.
Ok, Mike, U s/b set. I'm surprised that they didn't install you with MPEG4. Since LA is the 'home' of the West feed to HD DNS, I'm not sure of your status(Will they be turning it off because you have HD LIL?). And, why did they give you a new MPEG2 DVR(When they are already obsolete)? Whatever.

22 Miles is 'A Drop in the Bucket'. If there are sizeable obstructions between you and the towers that could be a problem. But, again, 22 miles is not far. You may need to experiment with your antenna location. Or, perhaps get a better antenna. Maybe a preamp(especially if your cable run is long).

There are many here who live in that area, and have better knowledge of that environment than I, and will be better able to give you ideas.

Good Luck!
....jc

miked2023

05-29-06, 12:41 PM

Thanks for your help. Now that I understand it a little better, I can see why my posts were somehat confusing. Hopefully I can keep my DNS feed b/c I live in the same market it comes from (can anyome confirm this.) As far as Mpeg 4 - Direct TV said they don't have it yet - and that they'd do an upgrade when the new one comes in - they'd better not charge me! Thanks again.

Rammitinski

05-29-06, 12:41 PM

Ok, Mike, U s/b set. I'm surprised that they didn't install you with MPEG4. Since LA is the 'home' of the West feed to HD DNS, I'm not sure of your status(Will they be turning it off because you have HD LIL?). And, why did they give you a new MPEG2 DVR(When they are already obsolete)? Whatever.

22 Miles is 'A Drop in the Bucket'. If there are sizeable obstructions between you and the towers that could be a problem. But, again, 22 miles is not far. You may need to experiment with your antenna location. Or, perhaps get a better antenna. Maybe a preamp(especially if your cable run is long).

There are many here who live in that area, and have better knowledge of that environment than I, and will be better able to give you ideas.

Good Luck!
....jcMike - check out your local area OTA HD thread if you're interested in improving your OTA reception.

Oldfart

05-31-06, 09:18 AM

I've been trying to buy a CM 7777 for over a month now. Can anyone explain the back order problem with this rather common pre amp?

etcarroll

05-31-06, 11:14 AM

I can't speak to the back-order, but I have one I never used, it overloaded my signal. It's been sitting in it's box in my bookcase.

If you want, make an offer.

Konrad2

05-31-06, 02:53 PM

My house came with a Winegard Colortron VHF/FM antenna in the attic.

5 active elements
1 reflector at rear
5 shorter (~ 2 feet) directors(?) on top of beam (To help with VHF-HI?)

impedance matching board with:
2 coils
1 resistor
1 balun
jumper for 300 or 75 Ohm

Is anyone familiar with this antenna? Google didn't find it.
I suspect it is from the late 1960s or perhaps the 1970s.

I'm wondering what sort of gain and beam pattern this thing has?

bobchase

06-05-06, 01:29 PM

I recall the discussion re "differential gain" in the broadcast antenna was concerning impact to nearby listeners
(e.g. under 5 miles for Bob Chase example), but there was no discussion re how a "small" frequency response
error across the 6 MHz bandwidth impacted receiver performance.

Consider the fol. Dielectric White Paper comparing two different types of broadcast antennas:
http://www.dielectric.com/broadcast/slotted.asp

The (probably worst case) Endfire antenna had differential gain errors as high as 4 dB, (fig 6a), which results in a differential delay of as much as 17 ns (fig 6b) at certain (close in) ranges. The (probably best case) Centerfed antenna had differential gain error of only 1.4 dB (fig 10a), resulting in differential delay of up to 7 ns (fig 10b) at certain (close in) ranges. Per Bob Chase's posted charts for his antenna, a down angle of 4 degrees corresponded to a range of 5 miles....of course YMMV.

Hence differential gain may be emblematic of an underlying broadcast antenna system deficiency, but uncompensated differential envelope delay is what will degrade ATSC receivers. For both of the above examples cited above, the "extra" differential delays will directly reduce the amount of multipath delay that can be corrected in the receiver's equalizer. It would probably take one of the latest 5th Gen ATSC Decoder chips to handle both the transmitter and multipath contributions. [Hopefully future Distributed Transmitter Networks would be far enough away to not cause even more problems....]

However, broadcast antennas may also have a local feedback system that provides pre-equalization in the exciter in order to minimize differential delay in the transmitted signal. This is primarily done to minimize the differential delay due to VSWR mismatch in the antenna system---but could also operate against differential gain.
What I would want to know is where is the "feedback" receiver is located (directly next to the broadcast tower?).
And could it be tweaked to minimize differential delay at the worst case range--at the expense of inducing a "small" amount of differential delay in the far field....

More on VSWR degradation to ATSC reception, expressed as an EVM (Error Vector Magnitude),
or more usually (erroneously) expressed as an increase in Noise Figure or a loss of sensitivity:
http://www.avsforum.com/avs-vb/showthread.php?p=5399965&highlight=dielectric#post5399965
http://www.tvantenna.tv/papers/PFactorsV.pdf
and searching out other papers published in IEEE Trans on Broadcasting by O. Bendov, Denise Schnelle and R. Evans Wetmore.
Holl_ands,
the newer generation of exciters can both actively and passively modify the 8-VSB errors for best reception. The older exciters only had a moderate active compensation ability.
For instance, if we were staying on ch39, I might chose to use our existing waveguide and end-fed Trasar antenna. If we did this (and had one of the newer exciters) we could calculate the combined group delay of the transmission system (waveguide, coax, & antenna) and have that coded into eprom by the manufacturer of the exciter. This is what I'm calling passive compensation because it requires no engineering or tweaking after the 1st day, even though it does use active circuitry to do this.
The active adjustments in the exciters use a reflected signal sample from the transmission line (post mask filter) to constantly optimize amplitude, group delay, and phase. I don't know of any exciter that uses an outboard receiver to make the compensation adjustments.
Transmitter adjustment (tune-up) procedure is to disable all exciter automatic adjustments, sweep (and adjust) the tubes for flatness, then combine the tubes. Next you tune the manual correction stages of the exciter for maximum flatness and minimum group-delay & phase error. Finally, you turn the automatics back on. With the newer exciters, the correction is said to be significant. On my older exciter, sometimes I see improvement, sometimes I don't.
As for modifying the signal for close-in reception, I doubt anyone would want try that. We have a 2000' stick and it would require a new antenna to just get a decent enough signal to the folks closer in than 4 miles before we ever even considered a form of pre-correction for them. (As more viewers go wired, companies are less inclined to spend money up at 2000'.)
Now having said that, some stations transmitters are in downtown or residential areas. Typically, these stations would be in the Northeast, like the DC area. Because their towers are much shorter (because of the higher ground elevation) the stations covering these cities often have their antennas designed for very close-in reception. The charts I posted some while back are basically true for a 2000' stick with a center-fed antenna, using moderate null-fill. An antenna without null-fill would have larger (deeper) valleys where there is little or no signal close-in. An end-fed antenna, like a Trasar, would have even a larger group delay error close in. A 1400' stick, like those in Indianapolis, would do better at 4 miles, because of the lower radiation center puts the more of the main beam over those homes.

Glad to see that you are still giving good advice out there.

Bob Chase
KHCW-DT

Konrad2

06-06-06, 11:52 AM

Bob Chase writes:

> Every antenna has it, some worse than others.

Is data on this available somewhere on the web, perhaps the FCC website,
or would we end-users have to ask an engineer at each nearby station?

> It is hard for a DTV tuner to put this back together because there is not
> enough equalization available to reassemble the ATSC data. If we were
> looking at a spectrum analyzer the signal would have huge notches in it
> like the worst multi-path you ever saw.

Are there artifacts of this in a NTSC picture? (For end-users without spectrum
analyzer.)

What would symptoms be for ATSC tuners? Inability to hold onto a lock?
Dropped packets?

Do some ATSC tuners (perhaps newer generation) do a better job than others?

> My bet is your are quite correct in that low gain antennas will out perform
> the high gain ones.

Because?

Konrad2

06-06-06, 01:53 PM

Jeff writes:

> FM interference appearing generally as diagonal "lines" on an NTSC video signal ...

I found some shielded FM traps, speced at -20dB 95-108 MHz each, and they helped a
lot, but I still get the diagonal lines sometimes, Varies from one day to the next.
Perhaps a clue there? I'd expect a normal FM station to be constant.

The next obvious step would be to hunt down a more aggressive FM trap that goes
down to 88 MHz, and hope it doesn't kill channel 6. And/or a tunable version.

Why not make the FM trap go up to 170 MHz or so instead of only up to 108 MHz?
Why not attenuate as much non-TV stuff as possible?

But could the diagonal lines be from something other than FM? A strong NTSC
station perhaps? Is there a formula to calculate the frequency of the
interference given the frequency of the victim channel and the slope of the
diagonal lines? I tried google but didn't find anything.

AntAltMike

06-06-06, 03:10 PM

The next obvious step would be to hunt down a more aggressive FM trap that goes down to 88 MHz, and hope it doesn't kill channel 6. And/or a tunable version.

Why not make the FM trap go up to 170 MHz or so instead of only up to 108 MHz?
Why not attenuate as much non-TV stuff as possible?

But could the diagonal lines be from something other than FM?

The FM band attenuation traps that evenly attenuate down to 88Mhz wreak havoc on channel 6.

You've already been advised of tunable FM notch traps, but you have decided that the affordable ones won't work in your situation due to ingress, notwithstanding the fact that they work just fine for those of us who install them professionally.

There are traps called midband traps that "notch out" 120 - 174Mhz. They are sometimes called A-I deletion filters. Channel Master used to make one, and I bought a few of them on a dealer closeout, but you wouldn't want to use such a product because it is in an unshielded case. Companies like Eagle Comtronics and Microwave filter make cylindrical, shielded A-I traps. Midband A-I traps often attenuate the channel 7 visual carrier by half a dozen dB. When I have seen them used in hotel PPV movie systems to clear the midband for PPV channel insertion, their visual degradation of channel 7 is readily discernible.

The likelihood that you can find an interfering carrier, if that is the cause of your undesirable symptoms, and mitigate it without test equipment, trap inventory or requisite technical expertise is nill. If you pay a competent technician with a spectrum analyzer and some traps to come out and analyze your reception situation and mitigate any RF spikes that may be contributing to your dissatisfaction, it will probably cost you less than $200.

Konrad2

06-08-06, 02:19 AM

> You've already been advised of tunable FM notch traps, but you have decided that the affordable
> ones won't work in your situation due to ingress, notwithstanding the fact that they work just fine
> for those of us who install them professionally.

I am not doubting your success, nor do I intend any insult.

It's just that, given what I've observed with unshielded RF devices from
reputable companies (that should know better!) that ADD interference, I
would prefer shielded devices over unshielded ones. Fool me once, shame
on you, fool me twice, shame on me, and all that. Silly me assuming that
products from companies with decent reputations would be designed properly!
If necessary, I could shield an unshielded device. If I really had to, I
could design and build a filter from scratch. But that seems like a lot
of trouble when shielded FM traps are available for $2-3. I now have some
shielded channel-6-killing FM traps on order, and eagerly await the magic
brown truck.

I'm also looking into midband traps.

Meanwhile, I'm wondering if there is a place to get a listing of FM radio
stations similar to the listing of TV stations at www.2150.com or antennaweb.org?
I looked there and also at fcc.gov but didn't find anything. I suspect that
finding a listing of things like NOAA stations would take some serious digging.

holl_ands

06-08-06, 05:34 AM

You can query the FCC database for AM, FM or TV stations within a specified radius:
http://www.fcc.gov/mb/audio/
You can select either html or text format, but unfortunately it's about two pages wide, so cut and paste into Word or Excel to extract distance/azimuth and other relevant info.

Much easier to digest: select "US state" option in the fol. link:
http://www.radio-locator.com/cgi-bin/home

or this very flexible search engine:
http://www.fccinfo.com/cmdpro.php?sz=M&wd=1152

Also of interest are these Quick lists showing ERP, but not location:
http://radiostationworld.com/north_america.asp

holl_ands

06-08-06, 04:39 PM

Location of NOAA Weather Alert VHF transmitters can be found here:
http://www.nws.noaa.gov/nwr/nwrbro.htm

In my location, they describe location by mountain top.
To find LAT/LONG, you might need to search by callsign in the FCC general database.

Since you are searching for possible VHF/UHF interference sources, don't forget Public Safety
also have assignments....typically CH14-20, but could be anywhere.

There may also be "experimental" or temporary assignmets that aren't in the lists.
To my great consternation, Qualcomm decided to quietly plant their 50 kW MediaFlow transmitter
on CH53 only a few miles away from my location.

And if unlicensed devices are approved for the "white spaces", many of your neighbors will become problems:
http://www.wirelessweek.com/article/CA6321135.html?spacedesc=Departments

Konrad2

06-10-06, 01:48 AM

Thanks, holl_ands, very useful info. I had been under the impression
that the low end of FM was supposed to be only low power stations.
Apparently that is not the case.

Or perhaps it used to be, but the FCC in their infinite wisdom abandoned
that policy along with the policy of not having TV stations on adjacent
channels. And if I'm reading Charles W. Rhodes correctly, even skipping
a channel isn't sufficient:

http://www.tvtechnology.com/features/digital_tv/02-16-05.shtml

Despite that, I may have fixed my diagonal lines problem by putting
a 95-108 FM trap *ahead* of the preamp. Yes the preamp is a respected
brand which is frequently recommended in this and other forums. And
yes, it has a FM trap built in. But it appears the builtin FM trap
is not good enough to prevent the preamp from doing the overload
cross-mod thing and scattering garbage here and there. The interference
comes and goes, so I'm not going to declare the problem fixed for awhile.
But it is looking very promising. Digital reception is much improved
as well.

holl_ands

06-10-06, 06:25 PM

Have you tried VHF/FM without the Preamp?
Perhaps the Preamp is only needed for certain VHF stations...or perhaps UHF only...
In which case there may be other options.....

If you have strong nearby VHF/FM stations and cannot get by using a UHF-only Preamp,
then you may want to try the Winegard HDP-269 low-gain VHF/UHF Preamp.

The specs indicate that it has 5 dB higher VHF overload than the best W-G and C-M Preamps....
and 12 dB higher than CM7777 for UHF.

A Preamp's primary purpose is to establish a good Noise Figure as close as possible to the antenna,
so that the effects of loss after the preamp is reduced by the amount of gain in the Preamp.
Higher gain doesn't make all that much of a difference to the overall SYSTEM NF.

More info re overload (and Preamp etal specs) can be found here (esp PPP 9, 11 & 13:
http://hdtv.forsandiego.com/messages/1/2846.html?1145308060

Konrad2

06-11-06, 01:36 AM

> Have you tried VHF/FM without the Preamp?

Not since I got the FM traps. I'll give it a shot.

Konrad2

06-11-06, 08:32 PM

The FM traps have helped a lot, but I think it is time for an antenna upgrade.
For UHF I'm planning on going with Winegard PR 8800 bowtie unless someone
has a better idea. I don't expect to need VHF-LO after the analog shutdown
and frequency swap.

I'm researching VHF-HI antennas. Here are the ones I have found so far:

Blonder Tongue BTY-LP-HB chan7-13 174-216 MHz
. . . . gain: 13.2 (ch. 7) 12.2 (ch. 13) dBi
. . . . Flatness Over Channel: 0.50 dB
. . . . beamwidth: 50.5 degrees
. . . . front/back: 20 dB
. . . . return loss: 12 dB
. . . . 10 elements
. . . . Length: 104 inches
. . . . Width: 35.5 inches
. . . . 13.25 lbs
. . . . Boom: alum 1.25" square 0.062" wall
. . . . elements: alum 0.5" round 0.049" wall
. . . . $ 282.99 @ http://www.solidsignal.com/prod_display.asp?PROD=SS4871
. . . . $ 322.24 @ http://www.starkelectronic.com/btp2.htm
. . . . http://www.blondertongue.com/reception/bty.pdf

Are radiation plots for the BTY-LP-HB available anywhere? I can't find any.

Winegard YA-1713
. . . . Boom Length: 99.875 inches
. . . . Max Width: 35 inches
. . . . Height: 3"
. . . . weight: 3.25 lbs
. . . . gain: 9.1-10.3 dBd
. . . . beamwidth: 40-56 degrees
. . . . front/back: 10.5-19
. . . . element diameter: 3/8"
. . . . $32.99 @ http://www.solidsignal.com/prod_display.asp?PROD=YA1713&main_cat=3&CAT=
. . . . $37.95 @ http://www.summitsource.com/winegard-ya1713-prostar-1000-10-element-offair-vhf-broadband-ch-713-yagi-high-definition-signal-outdoor-local-tv-aerial-antenna-blue-zone-part-ya1713-p-4589.html
. . . . http://www.winegard.com/offair/pdf/ya-1713.pdf

The YA-1713's radiation plots look okay, but I haven't found any elevation plots.

Winegard YA-6713
. . . . Boom Length: 49.875"
. . . . Max Width: 35 inches
. . . . Height: 3"
. . . . 2.15 lbs
. . . . gain: 6.8 - 7.3 dBd
. . . . beamwidth: 53-64 degrees
. . . . front/back: 6-18 dB
. . . . $24.95 @ http://www.summitsource.com/winegard-ya6713-prostar-1000-13-element-vhf-broadband-channel-713-yagi-high-definition-local-channel-outdoor-offair-signal-tv-antenna-aerial-red-zone-part-ya6713-p-4588.html
. . . . $24.99 @ http://www.solidsignal.com/prod_display.asp?PROD=YA6713
. . . . $26.97 @ stark
. . . . spec sheet: http://www.starkelectronic.com/wya6713.htm
. . . . http://www.starkelectronic.com/wnya6713.jpg
. . . . http://www.winegard.com/offair/pdf/ya-6713.pdf

Channel 7 radiation pattern has a significant looking rear lobe, which
would go along with the lame 6dB front/back ratio.
I haven't found any elevation plots.
The 1713 appears to have significantly better performance for only $8 more.

Antennacraft Y10-7-13
. . . . Boom Length: 120 inches
. . . . Max width: 35.75"
. . . . gain: 9.4 dB (d? i?)
. . . . beamwidth: 44.5 degrees
. . . . front/back: 16.5 dB
. . . . $33.51 @ http://www.starkelectronic.com/allant.htm
. . . . http://www.starkelectronic.com/acantena.htm

I haven't found any radiation plots for the Antennacraft Y10-7-13.

The gain plots for the Winegard YA-1713 at
http://www.hdtvprimer.com/ANTENNAS/comparing.html
look pretty bad, both raw and net. The curve is quite steep in places.

Are similar gain plots available somewhere for any of the other VHF-HI
antennas?

Why is the Blonder Tongue 10 times the price of the other antennas?
Is it really that much better? Or just a matter of selling a 10% better
product to commercial customers with deep pockets?

I am not especially concerned with signal strength. Any of these will likely
provide more than enough signal strength, even indoors without an amp. I am
concerned with most other aspects, including multipath (radiation pattern both
vert and horz), quality, durability, etc. These all have more beamwidth than
I need. 15-20 degrees would be plenty.

holl_ands wrote:

> 3. I would expect that a long Yagi antenna is adversely perturbed by
> the nearby attic structures more than the 8-Bay, although I haven't
> seen any NEC simulations on this aspect.

John wrote:

} I expect that the worst attic multipath effects are mitigated mostly
} by vertical directivity which would explain why 4 bay high bowtie
} stacks work well in attics.

Ron wrote:

] I'd like to suggest that the real issue is detuning of the antenna due
] to the close proximity of it's surroundings. Yagis are a much higher
] "Q" antenna a suffer much more detuning than a lower "Q" structure like
] the colinear.

Anyone have a guess as to how these VHF-HI antennas would perform indoors
or in an attic "looking" through a wood gable? Are they going to get detuned?
Rabbit ears indoors do pretty well, but have a bit more multipath ghosting on
analog than I'd like. I don't currently have any digital stations on VHF-HI,
but expect to have 2 maybe 3 after the big frequency swap.

The pr8800 UHF 8-bay is 34" high 45" wide. Multiply by 470/174 and a VHF-HI
version would be roughly 92" high 122" wide. I need a larger attic.

I've seen suggestions that the CM4228 can be used for VHF-HI as well as UHF,
but looking at the graph, the "frequency response" is shooting up and down
like crazy. That can't be good for reception quality.

Are there other VHF-HI antennas I should consider?

cpcat

06-11-06, 08:54 PM

For VHF Hi I can recommend the Antennacraft as well as the Funke psp 1922. The Funke has marginally higher gain and narrower bandwidth. I have a couple that I I'm not using at the moment. MAXHD has them as well the last I heard.

The BT antennas are commercial designs and that's where most of the added cost comes in.

holl_ands

06-12-06, 01:08 AM

The FM traps have helped a lot, but I think it is time for an antenna upgrade.
For UHF I'm planning on going with Winegard PR 8800 bowtie unless someone
has a better idea. I don't expect to need VHF-LO after the analog shutdown
and frequency swap.

I've seen suggestions that the CM4228 can be used for VHF-HI as well as UHF,
but looking at the graph, the "frequency response" is shooting up and down
like crazy. That can't be good for reception quality.

Are there other VHF-HI antennas I should consider?
Kerry Cozad of Dielectric (they make transmitter antenna systems) performed ACTUAL ON-THE-AIR
measurements of REAL antennas and found SMOOTH frequency response for CM-4228 in hi-VHF band:
http://www.avsforum.com/avs-vb/showthread.php?p=6423155&highlight=cozad#post6423155
Note CM4228 was much better than PR8800 (or any other tested antenna) in both VHF and UHF bands.

Ya gotta take the NEC computer simulation results with a grain of salt--and for very complex antenna structures better grab a mouthful...
Ya also should know that the CM4228 NEC results have been recently updated and were considerably different a year ago....

cpcat

06-12-06, 08:30 AM

The Antennacraft gain is in dBd.

http://antennacraft-tdp.com/pdfs/Y10-7-13.pdf

tobybul

06-12-06, 11:33 PM

Sorry, am sure this has been asked already. Recommendation on tv/hdtv antenna in Grand Rapids, Michigan area. Prefer multi-directional. Want to install in attic. Thanks

ziggy4212

06-12-06, 11:53 PM

The terk tv55 would be a good choice http://public.intranet.crutchfield.com/S-2QUFnjUJ3Py/cgi-bin/ProdView.asp?search=terk+tv55&i=209TV55

Rammitinski

06-13-06, 02:04 AM

If you're planning on giving that antenna a try, I'd suggest you buy it from some place where it's easily returnable.

Very few people have had much success with it.

kenglish

06-13-06, 07:12 AM

I would go with something outdoors, if possible.

Check the thread for your area, to see what channels are in use and their locations. You might be able to get away with a small UHF antenna, if the stations are all UHF. Otherwise, something in a small V/U antenna would be best. Attics are not optimal, although they sometimes work OK.

sebenste

06-13-06, 10:22 AM

Sorry, am sure this has been asked already. Recommendation on tv/hdtv antenna in Grand Rapids, Michigan area. Prefer multi-directional. Want to install in attic. Thanks

Hello Toby,

Unfortunately, you are in the same boat as Chicago...you have a digital TV station (specifically, WWMT) on VHF-LO, specifically channel 2, which is hard to pick up. If you want to do an attic, I would at least choose a Radio Shack VU-120 in size; or a medium-sized Winegard VHF-UHF combination antenna found at warrenelectronics.com, or starkelectronic.com. Unfortunately, if you have transmitting antennas in multiple
locations, then your roof may be your only real option for that antenna. I definitely would not usse the VU-120 outside, as that antenna, while picking up VHF quite well for such an antenna, is not made as sturdy as the others.

holl_ands

06-13-06, 01:02 PM

Sorry, am sure this has been asked already. Recommendation on tv/hdtv antenna in Grand Rapids, Michigan area. Prefer multi-directional. Want to install in attic. Thanks
Gotta know where you are to determine if you even have a ghost of a chance with
a "multi-directional" attic antenna.
Go to www.antennaweb.org and punch in your address/zipcode.
Then do a simple copy/paste of just the results table into a new post on this thread.
If you don't care about analog stations, then you can select just the digital stations.

AntAltMike

06-15-06, 05:32 AM

Kerry Cozad of Dielectric... performed ACTUAL ON-THE-AIR measurements of REAL antennas and found SMOOTH frequency response for CM-4228 in hi-VHF band:
http://www.avsforum.com/avs-vb/showthread.php?p=6423155&highlight=cozad#post6423155

Ya gotta take the NEC computer simulation results with a grain of salt--and for very complex antenna structures better grab a mouthful...
Ya also should know that the CM4228 NEC results have been recently updated and were considerably different a year ago....

I can't infer that from the graph that Kerry Cozad furnished. It plots single values of 4 dBd for channel 7, 4dBd at ch 9, 5dBd at ch 11 and 5dBd at 13 and then connects them with straight lines, but that does not contradict the data that can be extracted from the HDTV Primer plot for the same antenna.

The HDTVPrimer graph does have a much lower gain value for channel 7, but its center value for channel 9 is about 3dBd, channel 11 is 5 dBd and 13 is also 5dBd, so if you connected 9, 11 and 13 with straight lines on the Primer graph, it would be fairly flat like Cozad's, but look what a roller coaster ride the plots take between those center channel values! On the HDTVPrimer graph, the lower edge value of channel 9 is 0dBd, whereas its upper edge value is +5dBd:, the lower edge of 11 is +6dBd whereas its upper edge is -1dBd, and the plots of channels 7 and 12 gain are bad jokes, with the channel 7 plot shooting up by over 8dB over the first 1Mhz before plummeting 10dB across the remainder of the channel band, and the channel 12 plot looks like someone tuned a notch filter into it, measuring -1dBd at 204Mhz, troughing at -7dBd at about 205.5Mhz, and then recovering to +5dBd at 210Mhz, yet these plots are perfectly consistent with Cozad's primitive graph, which depicts the same spans as flat.

As I recall, Blonder Tongue specs for both their Yagis and log periodics claim flatness across each channel of 1dB or better. With analog signals, the color purity of channels 7 and 12 derived from the irregular response of the 4228 would be putrid (NTSC = Never The Same Color), and I am concerned that digital processing of similarly distorted signal plateaus would be unreliable.

sregener

06-15-06, 10:33 AM

With analog signals, the color purity of channels 7 and 12 derived from the irregular response of the 4228 would be putrid (NTSC = Never The Same Color), and I am concerned that digital processing of similarly distorted signal plateaus would be unreliable.

I can't answer for the 4228, but I have used my AntennasDirect 91XG as a VHF-HI antenna on channel 10 and find the color to be similar to that of the digital signal. This holds for a large variety of antenna positions, although there is one or two angles where the colors are very distorted. My guess is that the distortion of the 4228 at "optimum" angles is minimal as well. Maybe someone with a 4228 can post some real-world pictures of analog VHF-HI reception and put all our fears to rest...

Neonapple

06-15-06, 01:23 PM

Konrad2

06-15-06, 02:29 PM

> if you connected 9, 11 and 13 with straight lines on the Primer graph,
> it would be fairly flat like Cozad's, but look what a roller coaster
> ride the plots take between those center channel values!

Good catch!

> As I recall, Blonder Tongue specs for both their Yagis and log periodics claim
> flatness across each channel of 1dB or better.

Blonder Tongue BTY-LP-HB claims 0.5 dB

Looking at the Kerry Cozad graphs, I have to wonder. The Silver Sensor is a
small indoor unamplified UHF antenna, right? Then how does it get over 6 dBd
at channel 4 when it only gets about 4 dBd at best in UHF?

http://www.avsforum.com/avs-vb/attachment.php?attachmentid=45041
http://www.avsforum.com/avs-vb/attachment.php?attachmentid=45040

} Maybe someone with a 4228 can post some real-world pictures of analog VHF-HI
} reception and put all our fears to rest...

Awhile back, Bob Chase posted a pdf with actual spectrum analyser graphs from a
field test done 2005-09-18 in Pearland Texas. If I'm reading it right, on channels
5 & 9, the CM4228 is significantly more ragged than the Scala, HD7210, and CM5646.
Nearly 10 dB difference within channel 5, about 4 dB within channel 9.

Also interesting:

Compare the slope of the various antennas on channel 9.

Compare the slope of channel 35 with channel 36.

AntAltMike

06-15-06, 02:32 PM

I currently live in a highrise built in the 60's that uses a daisy chain method for antenna distribution on a continuous loop. Each unit in the tier taps into the trunk to receive signal from the line. Recently comcast entered my unit after there was a sever in the loop and found that my antenna wallplate was the cause. Rather than replace the plate, he disconnected the two ends from the plate and capped them with male coax connectors and then used a female-to-female coax joiner and simply bypassed my unit. Since I was using cable, I had no issues with it. For some odd reason certain local HD broadcasts do not come through on cable and wish to use the building antenna for HD OTA. Do any of you know where I can purchase a new wallplate that supports daisychain antenna connection on the back to coax connector on the front?

Since the two ends of the loop were capped, I would like to know if there is a wallplate available that has two female connectors on the back that maintains the loop rather than me uncapping the two ends and screwing the raw ends to the plate if at all possible.

The fitting removed is called a directional coupler or tap. It is an electronic valve that bleeds off a small amount of signal to your unit while passing most of it along for the units below. Radio Shack does NOT sell them, surely because selection and application of this product requires knowledge that most do-it-yourselfers don't have, and therefore would result in a lot of customer dissatisfaction and returns.

Taps have different values, denoted in negative dB. At the top of a tall building, the value might have been -24dB. In the middle, it might be -16dB, the last few floors will typically have values of -9 or -6dB.

How many stories tall is your building? Is there another wallplate in another room that you can remove to read the tap value off it, so that you can replace the missing one with the same value?

Were you receiving reliable HDTV signal from the antenna system previously? Very few master antenna systems in Arlington distribute UHF signal, though some of the older, smaller garden style apartments that are just overblown residential systems consisting of one antenna and one VHF/UHF distribution amplifier will get you several broadcast HDTV stations, provided there are no taller buildings blocking the direct signal path.

What apartment or Condo are you in? I've serviced the antenna systems in quite a few of them in your market.

Neonapple

06-15-06, 02:52 PM

The fitting removed is called a directional coupler or tap. It is an electronic valve that bleeds off a small amount of signal to your unit while passing most of it along for the units below. Radio Shack does NOT sell them, surely because selection and application of this product requires knowledge that most do-it-yourselfers don't have, and therefore would result in a lot of customer dissatisfaction and returns.

Taps have different values, denoted in negative dB. At the top of a tall building, the value might have been -24dB. In the middle, it might be -16dB, the last few floors will typically have values of -9 or -6dB.

How many stories tall is your building? Is there another wallplate in another room that you can remove to read the tap value off it, so that you can replace the missing one with the same value?

Were you receiving reliable HDTV signal from the antenna system previously? Very few master antenna systems in Arlington distribute UHF signal, though some of the older, smaller garden style apartments that are just overblown residential systems consisting of one antenna and one VHF/UHF distribution amplifier will get you several broadcast HDTV stations, provided there are no taller buildings blocking the direct signal path.

What apartment or Condo are you in? I've serviced the antenna systems in quite a few of them in your market.

Mike, Thanks for the response. I live in the condo complex called "The Carlton" which is the tallest building in the South Arlington area; so obstruction shouldn't be an issue. It's a 12 story building with me living on the 7th floor. I will go to my neighbors and check her wallplate for the tap value. I unfortunately tossed mine away after it was found to be defective. I do remember seeing a resistor on the back though.

Since you've serviced this area, would you know the dB from your highrise tap value black book before I bother her?

I didn't have an HDTV prior to the bypass, so I don't actually know if I will be able to receive HD or not. Either way, I would like to have this feature back in my unit for when I rent it out in the future.

Also I found this site that sells the couplers, but not plates.
http://www.pacificcable.com/Picture_Page.asp?DataName=201%2D306

I can probably get something like this once I know the tap and get the male-to-male to screw to the back of the plate from the coupler.

AntAltMike

06-15-06, 03:17 PM

I drive by it, but I don't think I've ever serviced it. Do you know who the management company is? I might know someone I can call to find out what the situation is there.

The ones with a visible resistor on the back are unshielded junk. Their tap value is usually printed in black ink on the plate itself. -12dB, -17dB and -23 or 24dB are common values for that kind of plate, whereas the more modern, shielded directional couplers are available in finer increments.

Neonapple

06-15-06, 03:21 PM

Mike,
The management company is "Armstrong Management." I also updated my post.

-Alex

AntAltMike

06-15-06, 03:23 PM

I service a few other buildings for them. I'll give someone a call next week sometime.

Neonapple

06-15-06, 03:31 PM

I appreciate your help. I am in no rush and thanks.

holl_ands

06-15-06, 07:37 PM

>
Awhile back, Bob Chase posted a pdf with actual spectrum analyser graphs from a
field test done 2005-09-18 in Pearland Texas. If I'm reading it right, on channels
5 & 9, the CM4228 is significantly more ragged than the Scala, HD7210, and CM5646.
Nearly 10 dB difference within channel 5, about 4 dB within channel 9.

Also interesting:

Compare the slope of the various antennas on channel 9.

Compare the slope of channel 35 with channel 36.
FYI: Here are links to Bob Chase's UHF-only outdoor vs attic antenna comparison and an attic location test:
http://www.avsforum.com/avs-vb/showthread.php?p=5399471&highlight=chase+attic#post5399471
http://www.avsforum.com/avs-vb/showthread.php?p=5410432&highlight=scala#post5410432
and here's Bob's VHF/UHF outdoor antenna test you cited above:
http://www.avsforum.com/avs-vb/showthread.php?p=6246260#post6246260

==============================================
When you see two strong adjacent channels, the transmitter and antenna have frequently been designed
as a single integrated structure. For example, NTSC CH8 and ATSC CH9 are different versions of KUHT.

However, antennaweb.org shows that ATSC CH31 and CH32 are on different towers in slightly different locations,
as are also ATSC CH35 and CH36.

Since ALL of the antennas experienced the SAME frequency response irregularities for CH35/36,
I would suspect either the transmitters or perhaps multipath conditions that affected all antennas equally.

===============================================
The CM4228 (cyan) has a variation of about +/- 4 dB on Low-VHF CH5,
but ya still have to be amazed that it has ANY gain for low-VHF channels and has more gain that any
of the other UHF antennas, including the SS-1000 Square-Shooter that still claims to be a "VHF/UHF" antenna.

Also bear in mind that most locations don't need much of an antenna for low-band VHF.
I've seen people strip off 12-18 inches of coax, leaving just the center conductor.
And Kerry Cozad's "coat hanger" antenna (see slides 11/12) also might be a viable candidate,
although I would take the time to unwind and separate the ends:
https://secure.connect.pbs.org/conferences/technology/2005/Sessions/TC05_43.htm

It would be interesting to see how the gain changes as the CM4228 is rotated,
since the max VHF gain isn't always aligned with the UHF beam direction....

And it is also possible that the spectrum analyzer was responding to multipath variations in
that particular antenna location vice gain irregularities as it slowly scanned across the channel.

Long experience has taught me that it is difficult to conduct on-air tests in "controlled" test conditions.....
Requiring numerous additional steps (usually not reported) to exclude other confusion factors....

===============================================
on High-VHF CH9 the CM4228 variation across the channel is only about +/- 2 dB.
Compare this to the best VHF/UHF Combo antennas which all experience a slight roll-off with frequency,
resulting in a variation of 2-3 dB. So on CH9, CM4228 has 4-10 dB less gain than purpose built
VHF/UHF Combos and is actually within +/- 2 dB, just like the Combos...

Note that the CM4228 is maintaining good energy across CH9, rather than rolling off like the VHF/UHF Combos.
An adaptive equalizer can overcome freq response irregularities much easier than trying to recover energy that is no longer there.

================================================
In NTSC, the audio carrier should be about 8-15 dB below the visual carrier:
http://www.sencore.com/newsletter/Nov03/HDTV_files/HDTV.htm
However, each station can chose a specific setting and what you see on a spectrum analyzer depends on
the bandwidth and integration time settings.
Hence overall, it appears that most NTSC channels are displayed with the audio carrier about 10 dB below the visual.

On NTSC CH11 and CH13, let's look at the relative strengths for the triple peaks (visual, chroma, audio).

On CH11, the three best VHF/UHF Combo antennas have about the same gain as the CM4228 for the visual carrier,
however the Combos also experience perhaps 6-8 dB EXCESS of gain for the audio carrier, the worst being the CM3671.
The CM4228 seems to be experiencing a gradual frequency rolloff, increasing to perhaps 6-8 dB for the audio carrier.

On CH13 the CM4228 APPEARS to be matching the gain of the best VHF/UHF Combos on the visual and audio carriers.
However, if you download and blow up the chart, you'll see that the CM4228 is providing 3-4 dB less gain than the combos.
This overall gain loss of 3-4 dB is also seen across the mid-channel frequencies, illustrating a generally flat response for the CM4228 on CH13.

So on CH11 and 13, the best VHF/UHF Combo antennas only provide a few dB more gain than the CM4228
and on CH11 experienced frequency flatness issues that are on the same order as the CM4228.

=================================================
BTW: STATIC, SMOOTH frequency response irregularities on the order of a few dB can be readily accommodated in an ATSC receiver's adaptive equalizer.
DYNAMIC and/or NOTCHED frequency response irregularities displayed on a spectrum analyzer are evidence of underlying multipath problems.

==================================================
YMMV: Anytime you measure antenna gain in a real-world location, the results will also reflect current multipath signal conditions. The nature of multipath can cause signal nulls and peaks that vary with location, meaning that one antenna may
experience a frequency response problem differently than the others.

Also, the Ground-Bounce reflection can cause as much as a 3 dB increase in measured gain at certain frequencies,
including those reported by Kerry Cozad using an outdoor antenna range. Reflections from nearby buildings can also inflate the measured gain.....

AntAltMike

06-15-06, 08:46 PM

...the SS-1000 Square-Shooter... still claims to be a "VHF/UHF" antenna.

And I claim that my paper clip is a VHF/UHF antenna. Winegard wants to sell Square Shooters (about $100 each, retail). They can sell more by calling it a combo antenna than by calling it UHF only. Most buyers who also wanted VHF capability may keep it even if it does not meet their expectations because of the investment they have in its installation, as well as the fact that it usually meets their UHF needs.

In fact, in many markets, like mine, the VHF highband final assignments aren't being used yet, so if anyone in this market bought one for that eventuality, he presently doesn't know if the Square Shooter will fail to meet his needs.

In NTSC, the audio carrier should be about 8-15 dB below the visual carrier:... However, each station can chose a specific setting and what you see on a spectrum analyzer depends on the bandwidth and integration time settings. Hence overall, it appears that most NTSC channels are displayed with the audio carrier about 10 dB below the visual.

I install antennas on tall buildings with clear, line of sight paths to about 16 full-powered analog transmitters ranging from three miles to about forty miles away. I usually use Blonder Tongue BTY-BBs or BTY cut-to-channel antennas for the VHF channels, and Winegard HA9065s or Channel Master CM-4228s for UHF. I don't go out of my way to check to compare the relative strengths of the visual and aural carriers, but I am virtually certain that they all consistently have a differential of 5 to 6dB, with the only possible exception being WMPT 22 analog from Annapolis.

The recommendation that the aural carrier be as low as 15dB below the visual carrier is the recommendation for relative levels of processed signals that are being mixed into an adjacent channel distribution system AFTER they have been faithfully received by the antenna. Strip amplifiers and channel processors typically include an analog tunable notch filter that is used to attenuate the aural carrier so as to minimize visual interference on the upper adjacent channel.

When you properly notch an aural carrier, you do not affect the chroma portion of the NTSC signal, but if you have an antenna that shows 10dB or more of differential between the aural and visual carriers, then it probably has about three dB or more of excessive attenuation of the chroma burst. I would consider that to be indicative of sucky antenna performance

YMMV: Anytime you measure antenna gain in a real-world location, the results will also reflect current multipath signal conditions. The nature of multipath can cause signal nulls and peaks that vary with location, meaning that one antenna may experience a frequency response problem differently than the others...

Also, the Ground-Bounce reflection can cause as much as a 3 dB increase in measured gain at certain frequencies,including those reported by Kerry Cozad using an outdoor antenna range. Reflections from nearby buildings can also inflate the measured gain.....

If a ground bounce were equal in strength to the desired signal AND if it hits the dipole exactly in phase with the desired signal AND if the antenna gain in the elevation of the bounced signal was as efficient as the gain in the horizontal plane, THEN, there would be a three dB increase in signal strength. You'd have to have a real world topography of a giant roller skating rink to even make that approach a physical possibility. Maybe, across Bonneville Salt Flat, you might be able to approach a three dB boost...

So on CH11 and 13, the best VHF/UHF Combo antennas only provide a few dB more gain than the CM4228 and on CH11 experienced frequency flatness issues that are on the same order as the CM4228...

It also would be interesting to see how the gain changes as the CM4228 is rotated, since the max VHF gain isn't always aligned with the UHF beam direction....

This Saturday, I'm going to be on the rooftop of a building in DC that has a BTY-BB pointed at analog channels 7 and 9, four miles away, another pointed at 11 and 13 maybe 35 miles away, and a couple of CM 4228s and HA9065s. It will be fairly easy for me to do some performance comparisons, and I'll also be able to visually compare the pictures of analog 11 and 13 coming off the BTY-BB and a CM 4228 on the 25" test TV in the mechanical room. Unfortunately, I am not outfitted to produce any kind of a screen capture, so I will be resigned to describing the picture quality as faithfully as I can.

I'll also compare the A/V ratio of analog channel 22 from WMPT from each type of UHF antenna used, to see if the 10dB differential I have measured in Arlington is local to that installation or if that might reflect the real carrier power differential.

holl_ands

06-15-06, 09:35 PM

bobchase

06-16-06, 12:37 AM

The relative levels of the visual and aural carriers depends on how you measure them.
I didn't immediately see what bandwidth Bob Chase used for these measurements,
but it must be much less than a MHz in order to resolve the individual visual/chroma/aural carriers.
If you are using specialized TV test equipment, the bandwidths of the separate visual and aural filters
are wide enough to include energy in the sidebands and hence will yield different ratios.

Looking at Bob Chase's charts for the UHF band, I see 3 and 6 dB minimum values and 11 db (twice) as the maximum values.
Discarding these anomalous extremes (might be antenna related), the remaining values are 10, 10, 8, 9, 9, 7 and 8
which averages to about 8.7 dB...so my first eyeball guess of 10 dB might be just a tiny bit high.

In the VHF band, CH6 has a ratio of 5, 7 or 9 dB, depending on which antenna you look at.
CH11 is 4 dB per the highest gain (CM3671) VHF/UHF antenna and 7 dB per CM5646 VHF/UHF antenna.
CH13 is 8 dB per CM3671 and 8 dB per Scala.
Holl_ands & AltAntMike
Back then I would have been using 100 kHz RBW with the display set to max (peak hold). I use 4001 data points for the sweep so that I am not skipping over frequencies on that large of a span with that narrow of an RBW. (The default is 401 data points.) Averaging would have been set to off.

If I leave the SA in max for 3 minutes or more, I will usually get all of the sync pulses captured from all the stations before I write the data file. Modern (common mode) transmitters always have some video on their audio carriers, so peak hold gives a slightly higher (1 or 2 dB) reading than what the real (average) aural power level is.

Typically, NTSC transmitters are set up for a 10% Aural to Visual power ratio. The FCC maximum licensed aural power is 20% of visual power and not all stations are licensed for that much. But even way back when we had separate aural & visual transmitters most UHF folks didn't run that high of aural power because of the electric bill. Some modern (common mode) transmitters have to be run down at 5% aural to make intermod specs. (I know of one station in Dallas that runs 3% aural.)

And I claim that my paper clip is a VHF/UHF antenna.
On a lighter note, I actually got some of them in the mail from a vendor. The clips were in little plastic bags labeled "Precision low-gain HDTV antenna" on one side and had "Installation Instructions" on the other. :rolleyes: Gota love those marketing types.

Bob

videobruce

06-16-06, 04:52 PM

With 4600 posts it's kinda impossible to read through them all.

For the TV engineers here (and I see a few), I would like to purchase a Spectrum Analyzer. The use it would have concerning this forum is to tune single UHF channel traps (filters if you prefer). Of course this is not the only reason, nor would it be the only time it would be used. Please don't waste any time telling me of a cheaper route to do this since this is a long term investment, mostly being used to the 2- way radio spectrum (and TV).

From what I have read, RBW is a important issue, but it also seems to take me out of the price range I want to stay in. Some have suggested RBW as low as 100 Hz or even 10 Hz, but that really seems overkill. Of the two units below only the Instek is a real RTSA and it has a RBW of 3kHz which seems ok to me. They do have a LCD version with 2.5 GHz coverage, but it is almost 2x the price.

Here are the links for the GPS-810 ($1750) from Instek and the Protek 3290 ($1900) which is only a "Field Strength" Analyzer, but it gives me 2.9 GHz coverage which the Instek doesn't.

http://www.instek.com/GSP-810.htm

http://www.protektest.com/ProdInfo.asp?prodId=3290

I also looked at the Avcom PSA-37XP ($3200) w/ 2.5GHz coverage, a LCD display, but at a much higher price tag and the RBW is only 75 kHz. The B&K 2630 ($1900) gives you a tracking generator, but the RBW is only 20 kHz if I read specs correctly;

http://www.avcomofva.com/products/default.asp?page=psa37xp

http://www.bkprecision.com/www/np_specs.asp?m=2630

It was also suggested to look at the used market which I did, but I'm not into 'boat anchors' especially considering the weight of some of these (60 lbs). While it doesn't have to be a handheld unit, I need some type of portability. Also, those $30k units from 20 years ago are way to much machine for me even though the prices are sometimes good if you can find someone that has them and can align them (I have and he was trying to sell me a Aglient 8650 or something close to that for around $3k).

Hope most of that made sense. :)

AntAltMike

06-18-06, 07:36 PM

Someone who has an Avcom "37" of some variety posted in another forum that Avcom wanted about $1,000 to fix it, and he was hoping that some member could point him to an independent repair company, which no one did. If that is a representative Avcom. out-of-warranty repair charge, then I'd say if any comparison between buying an Avcom product and a competing one is anywhere near close, I'd go with the other brand.

Anti-ant

06-18-06, 08:42 PM

Purchased house with existing antennae, didn't get all local UHF channels, but we were able to get sporadic Digital signal on our HDTV set, so we decided to purchase new Yagi style Antenna (43XG) from Antennas Direct. Once it was set up things were worse then before.

Debating on whether to go back to Cable, but aren't ready to get hit with the huge bill.

If anyone has any suggestions please advise.

-AA

Please post your experiences with antennas, preamps, all related equipment, and installation experiences. Indoor & outdoor. To include mounting, cabling, connectors, rotors, etc.

- Be specific; brands, models, sources, prices, etc.

- What works, what doesn't, and why?

- Tricks of the trade, and unique solutions.

Thanks in advance for your participation. AVS is only as good as it's members, and our members are the best.

enier

06-19-06, 08:55 AM

Purchased house with existing antennae, didn't get all local UHF channels, but we were able to get sporadic Digital signal on our HDTV set, so we decided to purchase new Yagi style Antenna (43XG) from Antennas Direct. Once it was set up things were worse then before.

Debating on whether to go back to Cable, but aren't ready to get hit with the huge bill.

If anyone has any suggestions please advise.

-AA

Start with antennaweb.org so you'll know the direction and distances of broadcast towers in your area. Then you'll have to decide which stations you want to get which will determine the antenna you need. A lot of times all you need to do is reposition the antenna to get most if not all the stations you want.

videobruce

06-19-06, 09:37 AM

AntAltMike; $1k to repair a $3k unit isn't really outlandish depending on what's wrong with the unit. With something that specialized I wouldn't be surprised that few if any would or even couild repair it. I doubt I would even consider sending to anywhere other than back to the manufacture.

Other than that, where are all the TV engineers in this thread with all that in depth topic discussion?? :cool:

sregener

06-19-06, 11:03 AM

If anyone has any suggestions please advise.

Well, your alias doesn't make me optimistic, but here's some advice for you.

First, if you want help on this forum we need more information than just what antenna you're using. Distances to the stations, frequencies (real, not virtual) of the digital signals, call letters of the stations you're having trouble with (as not all are broadcasting at high power or from tall towers yet), and what relative analog signals look like. A brief summary of terrain (trees, buildings, hills) between you and the transmitters would also be helpful. You should also include information on what, if anything, is connected between the antenna and your tuner (multiplexers, splitters, etc.) age of coaxial cable and connectors, and tuner model.

Once we have that, it should be easy to determine what the problem is and help you fix it, or tell you the problem can't be easily fixed.

Konrad2

06-19-06, 02:16 PM

AntAltMike writes:

> Unfortunately, I am not outfitted to produce any kind of a screen capture

There's always the old fashioned method: point a camera at the screen.

videobruce writes:

} With 4600 posts it's kinda impossible to read through them all.

I did. It takes awhile. You didn't miss a thrilling discussion on spectrum analysers.

} Some have suggested RBW as low as 100 Hz or even 10 Hz

I could see 10 Hz or even lower for audio, but it certainly sounds
like overkill for RF.

What RF application needs 10 Hz?

How are you going to display it?

A HD display at 1920x1080 would only give you a 19,200 Hz wide display.
A Apple/Dell $$$$ 30" 2560x1600 display will give a 25,600 Hz wide display.
A 1200 dpi laser printer with 14" paper gives at most a 168,000 Hz wide display.

} It was also suggested to look at the used market which I did, but
} I'm not into 'boat anchors' especially considering the weight of
} some of these (60 lbs).

} While it doesn't have to be a handheld unit, I need some type of
} portability.

Portable means it has a handle and fits through a submarine hatch. :-)

I've also been looking at spectrum analysers. For those of us who only
require submarine hatch level portability, does anyone have thoughts on
the Tektronix 7000 series SA plugins? I already have the mainframe.

Has anyone found a SA that connects to a computer? (e.g. a "plugin"
except using a computer for display instead of a scope/analyser mainframe)

At the very low end, there is the Digiair, available from solidsignal.com.
But at 1 pixel per channel, it doesn't look very useful. (It's really a
signal level meter with an extremely wimpy SA mode thrown in.)

I guess the real question that both videobruce and I have, is:
what is the least expensive SA that will get the job done?

videobruce

06-20-06, 07:27 AM

I don't understand your paragraph on video display resolution for HD or computer monitors as is has NOTHING to do with the subject.

The 100 & 10 Hz for Resolution BandWidth was a recomendation I have seen a couple of time for tuning filters, but I suspect they were talking about if filters at the board component level. Something I doubt I would ever do.

I have the option of the Protek 3201 or the Instek 810 at around $1700 for either with return privileges.

AntAltMike

06-20-06, 10:18 AM

I use a 100Khz bandwidth filter resolution when adjusting FM equalization notches in master antenna systems in which the FM is to be deliberately incorporated, but must not contribute to the overload of the distribution amplifiers. And in the instance of someone needing to attenuate the aural carrier of an NTSC channel where there is an ATSC channel immediately above it, like a channel 2 NTSC aural carrier at 59.75Mhz, without damaging the channel 3 NTSC pilot at 60.9 Mhz, a grade of resolution a little finer than 100 Khz would be helpful but not essential.

videobruce

06-20-06, 11:35 AM

Ok, Mike any anyone else, why are these other guys saying 100Hz and even 10Hz for a RBW?? :confused:
Where would one need something that tight??

AntAltMike

06-20-06, 12:22 PM

...why are these other guys saying 100Hz and even 10Hz for a RBW?? :confused:
So it won't seem out of place alongside their Lamborghinis. Or their 1080p TVs.

They may also prefer Monster Cable test leads.

videobruce

06-20-06, 01:34 PM

Not in these forums, I was referring to articles I have read from various sources.

Konrad2

06-20-06, 07:18 PM

bobchase

06-20-06, 11:57 PM

Ok, Mike any anyone else, why are these other guys saying 100Hz and even 10Hz for a RBW?? :confused:
Where would one need something that tight??
videobruce,
Narrow resolutions are often used for measuring phase noise and/or am noise on an unmodulated carrier or frequency source. The RBW (Resolution BandWidth) is basically the IF bandwidth of the analyzer. It does not equate to pixels, or more correctly, datapoints, in any way. It is a way to characterize how much energy is being analyzed.

Datapoints on the other hand, are how many samples are shown in the trace or recorded to disk. Too narrow of a RBW coupled with a low number of datapoints on wide sweeps leaves gaps where no energy is analyzed. Wide RBWs coupled with a high number of datapoints over the same sweep range causes the same energy to be included in multiple datapoints, and therefore unintentional averaging occurs. Both RBW and Video Bandwidth (VBW) need to be set for the job you are trying to do.

Mike is correct in using 100 kHz for 6MHz TV channels. 100 kHz RBW/30 kHz VBW and 30 kHz RBW/30 kHz VBW are the two most common setups for looking at a whole TV channel.

Bob Chase
Director of Engineering
KHCW

videobruce

06-21-06, 07:25 AM

Konrad2; OK, I understand now. Couldn't figure where you were comming from.

bobchase; Ok, where would one need anything less than 3kHz as two or three of my choices allow? How about a 'FM' broadcast signal or maybe a two-way transmission?

What do you think of this Instek 810 as a choice what what I have posted? I have the return option on the Protek, but I doubt that would satisfy me in the long run.

sregener

06-21-06, 08:30 AM

> I don't understand your paragraph on video display resolution
> for HD or computer monitors as is has NOTHING to do with the subject.

My point is that there will be so much data that there is no way
to display it.

A standard TV channel in the US is 6 MHz wide.

If you want a spectrum analyser to show you a graph that is 6 MHz wide
and resolve down to 10 Hz, you need a display with 600,000 pixel
horizontal resolution. I don't know of any display that has anywhere
near that resolution, whether CRT, LCD, plasma, DLP, or paper.

This is too easy.

I have a 6MP camera. The images are about 3000x2000 pixels. My monitor is only 1280x1080. How do I display the whole picture? Well, to see the whole picture, a bunch of pixels (way more than half) are discarded. But I can zoom in and only show a portion of the picture at a time and see each individual pixel. Likewise, with a SA, there should be no problem "zooming in" on the part of the spectrum you want to analyze.

Sure, you can't see the whole thing at once at that resolution. But who said you had to look at the whole thing at once?

AntAltMike

06-21-06, 12:03 PM

I doubt that it is even physically possible to construct a 10Hz wide filter with its center frequency in the RF broadcast band. If it was possible, it would be nearly impossible to determine the center value of such a filter with the precision needed to use it. And most RF signals under consideration would drift by more than 10 Hz, making them unsuitable for visual analysis on a display that repeatedly samples it and creates the illusion of a line by locating the briefly sustained images on top of one another.

Any advice to get a spectrum analyzer with an RBW of 100Hz or 10Hz was either a typo, leaving out the K, or was made by someone who didn't understand that this was to be used for RF frequencies.

While sreneger's exposition on how one views large digitized pictures on a screen with discrete pixels, the reality is, if someone is trying to analyze the quality of a TV channel, they really need to see the whole 6Mz at one time.

As far as I know, a monochrome CRT screen supports continuous variation in beam intensity and is therefore theoretically is capable of infinite resolution, but never achieves it because of other limitations of the tube and input source. The tunable bandpass filter that "sweeps" the band section selected for viewing is sometimes controlled by an analog voltage ramp generator, so horizontal resolution of that ramp cannot necessarily be conveniently counted in pixels.

WishIhadHDTVnow

06-21-06, 02:50 PM

I'm new and about to get an HDTV.
In my area, most stations brodcast in UHF, but their channel numbers range from 2 to 66. If i got an UHF only antenna, how would I receive channels 2 thru 13?

etcarroll

06-21-06, 04:14 PM

Start with antennaweb.org

holl_ands

06-21-06, 04:55 PM

When you copy/paste the antennaweb.org results, also provide your location (zipcode, preferably nearest cross streets) and whether there are nearby hills/buildings between you and the broadcast towers.

WishIhadHDTVnow

06-21-06, 05:00 PM

brad_arth

06-21-06, 05:18 PM

The 2-12 channels are a 'shortcut' per-se ...look at the frequency they are running at....I believe its the last catagory on that same page. That would be the number your looking at when talking about UHF.

brad_arth

06-21-06, 05:20 PM

lastplace

06-21-06, 09:48 PM

Antennaweb shows that I could use a medium directional antenna. I am having a hard time finding reviews of that type and finding the models. Any help or recommendations would be appreciated, thank you.

I have a channel master 4228 mounted in the attic with most stations 30 miles away, all 276 deg west-northwest. It works great. Purchased it locally for $69.

http://www.channelmaster.com/images/4228.jpg

holl_ands

06-22-06, 03:29 AM

Antennaweb shows that I could use a medium directional antenna. I am having a hard time finding reviews of that type and finding the models. Any help or recommendations would be appreciated, thank you.
In an earlier posts, you provided fol info:

channel - compass - miles - freq
6.1 - 87 - 4.6 - 22
3.1 - 90 - 4.6 - 45
7.1 - 89 - 4.6 - 20
26.1 - 120 - 6.7 - 17
42 - 194 - 17.7 - 42
15 - 194 - 17.7 - 15

The nearly right angle difference between two directions means that most "medium directional" antennas will have difficulty developing gain in both directions.
The 120 degree direction provides additional complication.

However, most of the stations are nearby and will be received with a strong signal no matter what antenna you use--although multipath may be a problem.

I would agree with sregener's earlier suggestion to try the inexpensive CM4221/3021 4-Bay antenna with a rotator.

However, you may get lucky without a rotator and be able to point the antenna towards the furthest away stations (194 degrees) and hope that your receiver isn't overwhelmed by multipath in the other directions. A lower gain antenna, like the DB-2 (a 2-Bay antenna) is probably better suited if you want to try this configuration since the right angle null depth is reduced.

=====================================
If you click on "antenna info" at antennaweb.org, they aren't very helpful describing a "Green", "Medium Directional" antenna, other than if you check the antenna patterns, they indicate that it should have same gain in ALL directions:
"These antennas include novel stick, wing shaped or disk antennas with long elements."

"Wing shaped" antennas probably refer to the Channel Master 3010 StealthTenna and Winegard GS-1100 Sensar, both commonly used with a Sat Dish for On-Air reception....
C-M hasn't posted antenna patterns and W-G only shows CH2, 9 and 50, where it has right angle nulls and would have less gain than the DB-2 for most UHF channels. Hence, they do NOT have the same gain in ALL directions. Would it work in your location??? Maybe--check around the neighborhood. Be sure to use the NON-AMPLIFIED model to prevent signal overload. And "point" the antenna so the wings do NOT point towards a desired direction.

"Disk antennas" probably refers to the C-M 3000A SmarTenna and the Winegard MS-1000....but they don't have "long elements"....whatever that is supposed to be....
These are true omnidirectional antennas with equal (zero) gain in ALL directions--seemingly just what you want... However, it also means no reduction of undesired multipath signal components... You might want to try it, but with zero gain, the station 17.7 miles away may cause problems...

So what is a "novel stick" antenna??? My guess is a 2-Bay or 4-Bay antenna.....and for now I'm "sticking" with that story....especially 'cuz we know they work....

holl_ands

06-22-06, 03:44 AM

"Start with antennaweb org "

That is where I started and the confusion arose. If a UHF antenna picks up channels 14 thru 69, and antennaweb showed some channels 2 thru 12 broadcasting on the UHF band. How does that work?
And then simply copy/paste the antennaweb.org results into a post, including your location (zipcode, preferably nearest cross streets) and general description of any nearby hills/buildings that may block the signal...

In antennaweb.org results, the REAL channel is in the LAST column, whereas the VIRTUAL channel number (e.g. 7.1, 7-1) points back to the original analog channel assigment.

videobruce

06-22-06, 07:04 AM

I doubt that it is even physically possible to construct a 10Hz wide filter with its center frequency in the RF broadcast band. If it was possible, it would be nearly impossible to determine the center value of such a filter with the precision needed to use it. And most RF signals under consideration would drift by more than 10 Hz I never really thought about that since I assume he/they were talking aboput $30-60k analyzers that wouldn't waste my time even taking a look at (because of price). I can't remember where I read it as I have been doing searches for information many times.

I appears Protek will be importing from GSI (actual manufacture) a new model. Unlike their "Field Strength" Analyzers it is label a "Spectrum Analyzer":

http://www.gsinstrument.com/eng/products/measure/rf_7830.htm

I have a unconfirmed price of $2600.

I'm still leaning towards the Instek 810. The tracking generator option adds another $580 to the base $1710 bringing it to $2290 which has to installed before you purchase (it isn't a user upgrade or retrofit after the fact). I know it's use for filters, but I don't know how much use I would have with it.
How could it be used for antennas to see the bandpass or could it?

WishIhadHDTVnow

06-22-06, 08:25 AM

"In antennaweb org results, the REAL channel is in the LAST column, whereas the VIRTUAL channel number (e.g. 7.1, 7-1) points back to the original analog channel assigment."

zip code 60099 Zion IL no hills or trees multiple level home
* yellow - uhf WTTW-DT 11.1 PBS CHICAGO IL 166° 41.1 47
* yellow - uhf WPWR-DT 50.1 UPN GARY IN 167° 41.1 51
* yellow - uhf WLS-DT 7.1 ABC CHICAGO IL 166° 41.1 52
* yellow - uhf WMAQ-DT 5.1 NBC CHICAGO IL 166° 41.1 29
* yellow - uhf WFLD-DT 32.1 FOX CHICAGO IL 166° 41.1 31
* yellow - uhf WCIU-DT 26.1 IND CHICAGO IL 166° 41.1 27
* yellow - uhf WGN-DT 9.1 WB CHICAGO IL 166° 41.1 19
* yellow - uhf WSNS-DT 44.1 TEL CHICAGO IL 166° 41.1 45
* green - uhf WXFT-DT 60.1 TFA AURORA IL 166° 41.1 59
* green - uhf WCPX-DT 38.1 i CHICAGO IL 166° 41.1 43
* red - vhf BAM-DT 2.1 CBS CHICAGO IL 165° 40.0 3
* red - uhf WPXE-DT 55.1 i KENOSHA WI 359° 44.5 40
* red - uhf WGBO-DT 66.1 UNI JOLIET IL 165° 40.0 53
* red - uhf WYCC-DT 20.1 PBS CHICAGO IL 165° 40.0 21
* blue - ufo WTMJ-DT 4.1 NBC MILWAUKEE WI 359° 44.2 28
* blue - uhf WISN-DT 12.1 ABC MILWAUKEE WI 357° 45.7 34
* blue - vhf WMVS-DT 10.1 PBS MILWAUKEE WI 359° 44.5 8
* violet - uhf WMVT-DT 36.1 PBS MILWAUKEE WI 359° 44.5 35
* violet - uhf WCGV-DT 24.1 UPN MILWAUKEE WI 359° 44.5 25
* violet - uhf WJJA-DT 48 IND RACINE WI TBD 359° 43.9 48

Now I'm beginning to understand it now. So the number to the far right is the number you would punch in on the HDTV tuner, right? So a UHF only antenna would suffice in my case, except CBS in Chicago. Thanks for helping me see the light.
Dan

sregener

06-22-06, 10:41 AM

So the number to the far right is the number you would punch in on the HDTV tuner, right? So a UHF only antenna would suffice in my case, except CBS in Chicago.

You could definitely do it that way. However, all stations include PSIP information with the virtual channels listed on the left. After you run the autoprogram feature on your tuner/television, you could punch in the virtual channels and it should tune into the stations the same.

However, as far as your antenna is concerned, only the real channel number matters.

At your distance, I doubt any antenna is going to get good reception of WBBM-DT on channel 3.

AntAltMike

06-22-06, 11:45 AM

...I'm still leaning towards the Instek 810. The tracking generator option adds another $580 to the base $1710 bringing it to $2290 which has to installed before you purchase (it isn't a user upgrade or retrofit after the fact). I know it's use for filters, but I don't know how much use I would have with it....

How could it be used for antennas to see the bandpass or could it?

I bought a white noise generator with a 5-2,000Mhz output and -10dBmV output level for about $300 that is the size of a cigarette pack. I think it was made by Applied Instruments. It broke once, a year after I bought it, and I think they charged me about $55 to repair it. I sometimes use that when I bench-test filters.

I think my Blonder Tongue BTSA4, which I keep for backup but never use because its tuning controls S-U-C-K, has an internal noise generator in it that can be accessed through a jack on the side of its case, using a special plug accessory that I don't have.

Sometimes, I have access to a franchised cable system that has digital channels starting from around 500Mhz to 550Mhz and use that to analyze my tunable UHF bandpass filter's roll-offs.

The spectrum analyzers I have owned don't have marker generators, so I don't have "hands-on" familiarity with them, but I guess they generate narrow frequency spikes that probably look like FM radio carriers. To tune a lowpass or highpass roll-off, you set one of those at the frequency you want to pass unimpeded and one at the frequency at which you believe you have interference and then tune the filter to perform optimally. To center or flatten a bandpass adjustment, you set one marker at the low end of the channel and one at the high end, and then center the adjustment within the mechanical range of the settings at which the two markers remain at equal strength.

videobruce

06-22-06, 01:29 PM

Is it better to tune a TV single channel trap (filter) with the actual signal as opposed to a generated signal??

AntAltMike

06-22-06, 02:18 PM

holl_ands

06-22-06, 02:30 PM

An off-the-shelf RF Noise Gen for $300 sounds pretty good.

However, I am aware of at least one RF Noise Gen Kit for $39:
http://www.elecraft.com/manual/N-gen%20man%20rev%20C.pdf
http://www.elecraft.com
Search for the NGEN Kit in the Mini-Modules section--note user comments at top of the page.

The NGEN specs say within 3 dB from 100 kHz to 500 MHz, although the Minicircuits MAR-1
spec sheet shows only 3 dB down at 1000 MHz:
http://www.minicircuits.com/cgi-bin/spec?cat=amplifier&model=MAR-1&pix=vv105.gif&bv=4
After all, why would a Ham radio operator need anything above the 434 MHz Amateur TV band....

If $39 still seems like an outrageous price, then you might want to simply connect the
noisy output of a zener diode to the input of an extra VHF/UHF Preamp.

holl_ands

06-22-06, 03:09 PM

The fol. Dallas-Maxim App Note also describes a DIY Noise Gen project using a variety of zener diodes:
http://pdfserv.maxim-ic.com/en/an/AN3469.pdf
They decided to cascade two MAX2611 Amp modules (3 dB down at 1100 MHz),
so the response probably falls off gradually beyond the "flat" 100 MHz section they chose to display.

=====================================
Another Noise Gen DIY experience:
http://astro.u-strasbg.fr/~koppen/RJove/calibrator.html

=====================================
FYI: www.noisecom.com also makes Noise Sources and Noise Diode components.

barchamb

06-22-06, 07:12 PM

Konrad2

06-22-06, 07:49 PM

> I need a rotator, or a strong omni, correct?

Keep in mind that a rotator means that 2 people can't watch
two different shows at once. Or 1 person and a DVR.
A DVR is unlikely to be able to move the rotator.

Keep in mind that a omni is more likely to add multipath.

Another option is 2 antennas. You can use 2 downleads and a
switchbox, or use a "Join-Tenna" or similar. You might be able
to get away with using a splitter backwards, if it doesn't
add too much multipath.

You may want to find out if these stations will stay UHF, or
if they will move to VHF after the analog shutdown and frequency
swapfest.

Also note that 15 is listed as "red", so you might need a
higher gain antenna for it. You could try pointing your DB2
at KSBY and see how well it does.

http://www.warrenelectronics.com/Antennas/joiners.htm

[ Not an endorsement of warrenelectronics.com or the Channel Master
Join-Tenna. I've never used either of them. Word is that the
Join-Tenna is not shielded. ]

barchamb

06-22-06, 09:42 PM

Thanks for the tip on the join-tenna. However, it works by blocking out a certain range of channels. The channels I care about are 15, 19, and 27, and the join-tenna blocks 14-29, 30-49, or 50-69, so it would basically block all the channels I care about instead of blocking 2 and letting one through, which is what I would need.

And, as you state, the whole point is to use the DVR, so a rotator is out of the question. Sounds like I'm kinda screwed, huh?

TotallyPreWired

06-22-06, 09:50 PM

Thanks for the tip on the join-tenna. However, it works by blocking out a certain range of channels. The channels I care about are 15, 19, and 27, and the join-tenna blocks 14-29, 30-49, or 50-69, so it would basically block all the channels I care about instead of blocking 2 and letting one through, which is what I would need.
Nope. They are tuned to the correct frequency. So, the 14-29 can be tuned to a frequency within that range. However, expect 1 - 2 channels either side of the required frequency to be blocked.
....jc

bobchase

06-22-06, 10:01 PM

videobruce
If you want to know about tracking generators and spectrum analyzers, check out the agilent website. Look for Application Note AN-150 for starters. It's a huge PDF but it's full of information about SA's, how to set them up, and why. There is a wealth of info on that website, including operation manuals. While you probably will never need to own one, the App Notes and the Op Manuals can take you way past SA 101.

Bob C

holl_ands

06-22-06, 10:17 PM

It is better to tune it in-circuit, since you can see the tradeoff between preserving the desired signal and attenuating the undesired one. I often have to pass a digital channel 48 while attenuating an analog chanel 50 from one antenna, and then mix that with the signal from another antenna that receives the analog channel 50 while attenuating the channel 48. At UHF frequencies, that takes some compromising, so I can best evaluate my compromise by evaluating the performance of the filter on the signals to be attenuated.
When you tune some notch filters, the tuning can change if it has a removable box or lid....and of course you should use a non-metalic tuning wand. If this detuning occurs, you could inject an opposite amount of detuning to compensate.

How accurate do you need to be? The bandwidth of the video carrier is fairly wide and the FM aural carrier signal is about 200 kHz wide...but you're trying to center the notch on the carrier spike...so probably within 10-30 kHz or so.
http://www.sencore.com/newsletter/Nov03/HDTV_files/HDTV.htm
Note you can check FCC database to see if an NTSC station has been assigned a freq offset up or down by about 10 kHz...with a tolerance of under 1 kHz.

=====================================
If you have a choice of spending $300 on a RF Noise Gen or $300 on a Tracking Generator option for the Spectrum Analyzer, I would probably favor the latter because it is more flexible and makes it much easier to print out a nice smooth frequency response plot, rather than looking for the location of a fuzzy "notch" in a random noise curve.
The (expensive) tracking generators I've used provide a rapid sweep through the band so you can immediately see the displayed frequency response curve as you tweak the device.

====================================
Another consideration with an RF Noise Gen is the available dynamic range. The Instek noise floor seems to be -100 dBm (typical) for 220 kHz VBW, which is equivalent to -153 dBm/Hz. That's -82 dBm for 6 MHz bandwidth. [Note that the specs are confusing...maybe the noise floor is -95 dBm, in which case subtract 5 dB from the dynamic range.]

The API NS-1 output spec is -39 dBm for 24 MHz bandwith, which is equivalent to -113 dBm/Hz. That's -45 dBm for 6 MHz bandwidth. So you can display a notch depth of not quite 37 dB.

The $39 NGEN Kit claims 35 dB "excess noise", (i.e. more than -174 dBm/Hz thermal noise floor), which is a noise output level of -139 dBm/Hz. That's -71 dBm for 6 MHz bandwidth. So you can display a notch depth of not quite 14 db...so you'll need to use a Preamp with the NGEN to pump up the dynamic range.

AntAltMike

06-22-06, 11:39 PM

When you tune some notch filters, the tuning can change if it has a removable box or lid....

Blonder Tongue actually sells an overpriced "tuning cover" to use when tuning the 10dB notch trap in its single channel UHF preamps. It is basically a metal cover with a tiny hole in it.

A funny thing about tuning Winegard UT-2700s is that even though the adjustable tuning component is a capacitor, which is non-inductive, it is in the proximity of inductive circuitry, so an inductive tuning tool will throw off the tuning value just by being near some other component when adjusting those variable capacitors. These appear to be the same variable capacitors that I have no trouble tuning in MX-4U 4-channel combiners (discontinued a decade ago, but I have a stash that I won't share with anyone at any price!) using the smaller of the two, Radio Shack, anti-static blade-type tuner adjustment tools, but when I remove the tool from the UT-2700s, the notch moves, so I first see what the maximum benefit is that I can get with the tool installed, then I misadjust it a little to the left and right until, upon removal of the tool, the notch jumps back to where it had been optimal with the tool inserted in the capacitor's slot.

The slot on those tunable capacitors is really slim, and I haven't yet found a non-inductive tuning blade. If anyone can recommend one, I'll buy it and give it a shot.

holl_ands

06-23-06, 01:52 AM

Here is my antennaweb.org info:

* yellow - uhf KCOY-DT 12.1 CBS SANTA MARIA CA 99° 20.7 19
* yellow - uhf KEYT-DT 3.1 ABC SANTA BARBARA CA 123° 47.3 27
* yellow - uhf KTAS-DT 34.1 TEL SAN LUIS CA 326° 23.9 34
* red - uhf KSBY-DT 6.1 NBC SAN LUIS OBISPO CA 327° 23.9 15

I currently have a DB-2 mounted in my attic, and with that, I get 19 with anywhere between 80 - 100% signal, and 27 with anywhere between 50 and 75% signal. However, I am not getting a signal from 15 at all. Looking at the "View Street Level Map", the elements (bowties) on my DB-2 are pointed roughly in the direction of 19 and 27. In my area, 19 was the only station broadcasting HD anyway, the others were just retransmitting their SD content, so I didn't care about 15. Now 15 is doing HD, and I'd like to get both. Since they are pretty much in opposite directions from each other, that probably means I need a rotator, or a strong omni, correct?

Just a few quick comments:

1. FCC database shows an analog K15DB (KTBN repeater) Santa Barbara station on CH15,
which could block reception of KSBY-DT from SLO:
http://radiostationworld.com/Locations/United_States_of_America/California/tv.asp?m=sba

2. Although antennaweb.org shows it as "yellow", an omni will probably not be adequate for KEWY,
since it is 47 miles away.

3. You might want to try inexpensive CM-4221 4-Bay with rear reflector screen removed so it is bi-directional.

4. And moving the DB-2 outdoors might even work...

videobruce

06-23-06, 09:29 AM

It is better to tune it in-circuit, since you can see the tradeoff between preserving the desired signal and attenuating the undesired one. As in using the actual TV signal as opposed to a 'test' signal from a TG? After all, why would a Ham radio operator need anything above the 434 MHz Amateur TV band.... Because privileges extend well above 440. Who said anything about Ham radio?? ;)
holl_ands; A broadband noise generator would be as good as a tracking generator??

bobchase; I have been to Agilents' site, but their application documents seem to be way above me (at this point anyway). I will take another look though. I also have been at Sencores' site and came across some articles, but those seem to be just the opposite of Agilent; a little too basic. I need something in between. When you tune some notch filters, the tuning can change if it has a removable box or lid The older filters are externally tunable. The newer traps are CATV type cylinders that would have to be opened to be re-tuned. It's the older ones that I would be tuning. (no problem)

holl_ands; Just saw and printed that Sencore link yesterday. Nice brief reference for DTV signals. If you have a choice of spending $300 on a RF Noise Gen or $300 on a Tracking Generator option for the Spectrum Analyzer, I would probably favor the latter The TG option for the 810 is $600. At $300 I wouldn't have a issue, but since I can get the Instek 810 for UNDER $1700 (competition is getting hungry) I don't see the value for me.

videobruce

06-23-06, 09:39 AM

A update on the choices.

Protek 3201 $1375
Instek GSP-810 $1675 (w/ TG $2265)
New:
Protek 7830 "Spectrum Analyzer" under $2600.

I requested a owners manual. Here is the spec sheets. I compared this with the 3201/3290 and I am puzzled regarding them calling this a "Spectrum" Analyzer since there is NO RBW listed in the specs. The only 'bandwidth' that is listed is the same for the 3201/3290; Modulation Bandwidth: Narrow FM:12.5 kHz, AM/SSB:2.4 kHz and Wide FM:180 kHz all at -6db They also list a "step range"; AM/SSB:2.5 kHz fixed. FM:6.25 kHz It still seems as this 810 is the best buy, but I don't want to rule out the others yet.

apotocki

06-23-06, 10:39 AM

videobruce

06-23-06, 10:51 AM

Geting back to the 100 & 10 Hz RBW recomendations, the following was taken from Agilents' app. note AN 1315: RBW filter:
Since noise is a function of the RBW filter, use caution when interpreting phase noise or DANLspecifications.
Phase noise specifications are normalized to a 1 Hz RBW filter even if the analyzer does not have a 1 Hz RBW filter. In order to determine the actual achievable phase noise level, it is necessary to convert from the specified 1 Hz RBW to the actual RBW filter used for the measurement. The correction factor is determined as follows: Phase noise level correction (dB) = 10 log (actual RBW /1 Hz)
For example, the phase noise specification for the Agilent E4411B at a 10 kHz offset is –90 dBc/Hz, but the minimum RBW setting is 10 Hz. The correction factor for the 10 Hz RBW is: 10 log (10 Hz/1Hz) = 10 dB. Taking this correction factor into account, the actual achievable phase noise is –80 dBc in the analyzer’s minimum RBW of 10 Hz.

videobruce

06-23-06, 11:10 AM

is the indoor antenna not getting good enough reception? .........is the 25db gain overpowering the tv? Possibly. See this;
http://www.avsforum.com/avs-vb/showthread.php?p=7625830&&#post7625830

sregener

06-23-06, 01:04 PM

My first thought was that I need a better antenna.....but before going through that, I wanted to get additional opinion/feedback.

Yes, you need a better antenna. Not more expensive, just better. That RCA is a piece of junk. Return it while you still can.

Good indoor antennas are the Terk HDTVi or Zenith Silver Sensor, both of which run about $30. Another good choice, although it doesn't come with a stand is the AntennasDirect DB2. Radio Shack makes an excellent indoor antenna, the 15-624 which runs about $15. If you're getting nearly perfect reception with the RCA, any of these should be more than adequate.

holl_ands

06-23-06, 03:46 PM

Hi - rather new to the forum and have found a wealth of information in it.

I recently purchased my HDTV (50 inch Sony) and have a question relating to HDTV reception. I'm not in a position right now to 'upgrade' my cable (WOW) to include the HDTV channels so I went out and purchased an indoor RCA (ant585) which is a powered antenna with 25db of gain (cost $39.95).
I connected the antenna and the TV recognized (found) all my local HD stations.
The stations all come in looking good....but.....here is my problem/question.
It appears that all of the stations experience intermittent sound cut-outs (only lasting for a second or two) and even less occasional picture 'glitches'. Any ideas? Is this just the nature of the local HD broadcasting? or, is the indoor antenna not getting good enough reception? or, is the 25db gain overpowering the tv? I do not experience this with the cable channels.
My first thought was that I need a better antenna.....but before going through that, I wanted to get additional opinion/feedback. I'm about 20 miles from all of my local HD stations with no buildings and just a couple trees nearby.
Any and all feedback/suggestions are appreciated.

Thanks
Alan
Location, Location, Location.

Get the antenna as high as is feasible (mine's at top of living room cathedral ceiling).....and attic is must better if you don't have to adjust it.....and outdoors is always best....
Get it away from other metallic (and wooden) objects as much as is feasible.
And placing it near or preferably pointing through a window towards the towers will usually find a stronger signal.

You didn't say where you were located (zipcode, preferably nearest cross streets), buildings/trees/hills in the way....
If there are no "nearby" stations (within about 10 miles) then I would recommend trying an amplified indoor antenna, such as the fol. amplified variant of the Silver Sensor, which also adds rabbit ears for VHF channels:
http://www.amazon.com/gp/product/B000B58VNM/ref=pd_cp_e_title/103-9253623-8723050?%5Fencoding=UTF8&v=glance&n=172282

Terk makes an amplified VHF/UHF equivalent, the HDTVa, but it costs more and is not enclosed and hence isn't as resistant to abuse:
http://www.amazon.com/gp/product/B0007MXZB2/ref=nosim/103-9253623-8723050?n=172282

To make sure that there aren't any nearby low-power stations that could overload an amplified antenna, your location needs to be entered into www.2150.com/broadcast with say a 30 mile radius and be sure to check the "List Low Power" and "List Analog" boxes.
Just to make sure there are no surprises....

Konrad2

06-24-06, 12:26 AM

> Get it away from other metallic (and wooden) objects as much as is feasible.

Why the recommendation to keep antennas away from wood? I've read that
dry wood is fairly transparent to RF.

holl_ands

06-24-06, 07:07 PM

> Get it away from other metallic (and wooden) objects as much as is feasible.

Why the recommendation to keep antennas away from wood? I've read that
dry wood is fairly transparent to RF.
At the time, I was thinking about "wooden" RPTV and equipment cabinets that might have veneer over metallic frames....with metallic objects inside....including CDs & DVDs with metalic film.

However, I would also be concerned about nearby objects (whether metallic or "semiconductor" wood) perturbing an indoor antenna's gain pattern and esp. VSWR.

=============================================
NIST measured the attenuation of various dry and wet building materials from 500 MHz (UHF CH19)
up through 800 MHz (UHF CH69) and higher:
http://fire.nist.gov/bfrlpubs/build97/art123.html
They also tried to correlate attenuation and material density if you want to predict for other materials...

CH19, CH69:
0.2, 0.6 dB for 1/4 inch (5.7 mm) Single Pane Glass
1.3, 1.8 dB for 1/2 inch (12.5 mm) Single Pane Glass

0.35, 0.6 dB for 3/4 inch Plywood Sheet (Dry)
0.75, 1.2 dB for Two 3/4 inch Plywood Sheet (Dry)

2.0, 2.6 dB for 1.5 inch Spruce-Pine-Fir Panel (Dry)
1.4, 2.1 dB for 3 inch Spruce-Pine-Fir Panel (Dry)
2.0, 3.1 dB for 4.5 inch Spruce-Pine-Fir Panel (Dry)
4.4, 5.5 dB for 6 inch Spruce-Pine-Fir Panel (Dry)

Note the big jump from 1/4 inch to 1/2 inch Glass....very strange...
Also note the attenuation was LESS for the 3 inch thick Panel--even though it was constructed
with criss-crossed 2"x12" planks with less leakage in the cracks....very strange...

So the calculated attenuation through a "typical" roof with a 3/4 inch Plywood Sheet with
100 percent overlap for 3/8 inch thick shingles would be about 0.75 for CH19 and 1.2 dB for CH69.

Which doesn't correlate at ALL with the 13 dB +/- 7 dB attic loss actually measured.

An unexpected result even if some of the more modern ones skew the results with mylar foil backing on insulation....and at least some receive the signal at an angle through multiple 2x12s...

Clearly wooden 2x4s are capable of significantly perturbing the electromagnetic field and I would thereby expect them to perturb the antenna pattern and VSWR of any nearby antenna.

holl_ands

06-24-06, 08:15 PM

Re. my "eyeball" estimate of about 13 dB +/- 7 dB for indoor and/or attic loss....
Most are unspecified "indoor" locations, so it's difficult to determine whether the height gain
of an attic location is included or not...

And recall that Bob Chase measured roughy 20 dB of loss in his attic....

Here's a 265 page "ATSC Seminar" posted on Zenith's website which summarizes indoor/attic
loss measurements conducted to validate DTV coverage, starting on page 181:
http://www.zenith.com/digitalbroadcast/downloads/Seminar%20Appendix.pdf
BTW: It's a 6.7 MB file.

And here are the 525 VU-graphs that goes along with it:
http://www.zenith.com/digitalbroadcast/downloads/Seminar%20Slides.pdf
BTW: It's a 9.4 MB file.

I know there's a link with only the 19 page summary, but I couldn't get my hands on it....

===============================================
EDIT (12Oct2009): Above links no longer available on Zenith website.
Following is a much shorter 65 VU-graph summary:
http://www.iptv.org/dtv/2001/webpresentations/gsgrignolizenith/index.htm

gioux

06-25-06, 08:17 PM

holl_ands

06-25-06, 08:51 PM

So I briefly tried getting HD over the air. So far no luck, but will keep trying. Here is the interesting thing though. I have regular old cable, do not pay for HD. I just plugged the coax into my TV. The TV appears to be getting HD channles, and it lists them as 720p or 1080i on the display and 16:9 (I have a Sony 32" xbr1). Does that mean that I am getting HD or does everyone pick up those channels but you only get real HD display if you pay? Anyone have any ideas? Thanks!
On most cable systems, the LOCAL HD channels are being carried as an unencrypted QAM digital signal,
as is mandated by Federal Law to be available as part of BASIC CABLE....for no additonal cost...

DCR (Digital Cable Ready) HDTVs can receive these unencrypted QAM channels without a CableCard decryption module.

Unfortunately, the cable systems go out of their way to not advertise this Federally Mandated requirement...

Neil L

06-25-06, 10:48 PM

On most cable systems, the LOCAL HD channels are being carried as an unencrypted QAM digital signal,
as is mandated by Federal Law to be available as part of BASIC CABLE....for no additonal cost...Unfortunately, the cable systems go out of their way to not advertise this Federally Mandated requirement...Where I live, ALL local HD stations are encrypted. Only way to get them on cable is to subscribe to the HDTV package, and subscribe to the digital TV package, and rent the cable box, and if you want HD-PVR thats another ten bucks a month. Sheesh, if there really are FCC rules and regulations (I doubt that there are Federal Laws) that mandate clear QAM on basic cable, these folks are in violation big time.

Sorry for helping to take this so far off the antenna topic. Just had to vent.

sregener

06-26-06, 07:52 AM

On most cable systems, the LOCAL HD channels are being carried as an unencrypted QAM digital signal,
as is mandated by Federal Law to be available as part of BASIC CABLE....for no additonal cost...

I don't think there is any such law yet. Cable systems aren't even required to carry the local HD channels (i.e., no "must-carry") let alone send them in a specific manner or package.

videobruce

06-26-06, 08:27 AM

Are you sure it doesn't extend to digital channels??

AntAltMike

06-26-06, 09:10 AM

deconvolver

06-26-06, 11:45 AM

Where I live, ALL local HD stations are encrypted. Only way to get them on cable is to subscribe to the HDTV package, and subscribe to the digital TV package, and rent the cable box, and if you want HD-PVR thats another ten bucks a month. Sheesh, if there really are FCC rules and regulations (I doubt that there are Federal Laws) that mandate clear QAM on basic cable, these folks are in violation big time.

Sorry for helping to take this so far off the antenna topic. Just had to vent.
The FCC does require that the cable company provide a cablecard if you request it instead of an HD set top box. That should save a few bucks if you have a TV with a cablecard slot.

washtenaw

06-26-06, 02:16 PM

holl_ands

06-26-06, 03:18 PM

edit: nevermind, there are converters to be found everywhere :)

I'll leave my questions just in case... now I just to have to pull up some floorboards in the attic in order to see the best way to go about fishing the cable from up there to the room below.

I just got my LCD and xbox is a beauty on it. However, that's about all I can do with it until I get the 15-624 I just ordered from Radio Shack based on recommendations given in here.

I have a question about this antenna. What products are recommended for converting the twin-lead to coax -- is it balun or bust? Where would I be able to find these products? The run will not be terribly long (20 feet at most) from my attic.

Thanks in advance, and your patience with the complete newb questions :confused:
Radio Shack also sells Baluns, like these:
http://www.radioshack.com/product/index.jsp?productId=2103912&cp=&origkw=15-1140&kw=15-1140&parentPage=search
http://www.radioshack.com/product/index.jsp?productId=2062049&cp=&origkw=15-1230&kw=15-1230&parentPage=search

Connect the twin-lead on the Balun to the antenna.
The other end of the Balun connects via standard coax down to your TV.
For a short run, lower cost RG-59 coax (Radio Shack again) is quite suitable and expensive RG-6 is overkill.

To minimize noise pickup and minimize loss, it is best to connect the Balun as close as possible to the antenna terminals rather than to the end of the twin-lead that comes with the antenna.

washtenaw

06-26-06, 03:37 PM

Radio Shack also sells Baluns, like these:

(snip)...

Connect the twin-lead on the Balun to the antenna.
The other end of the Balun connects via standard coax down to your TV.
For a short run, lower cost RG-59 coax (Radio Shack again) is quite suitable and expensive RG-6 is overkill.

To minimize noise pickup and minimize loss, it is best to connect the Balun as close as possible to the antenna terminals rather than to the end of the twin-lead that comes with the antenna.

Thanks a ton for taking the time! Weird that product searches for 'balun' really don't turn up much.

newsposter

06-26-06, 04:06 PM

this forum or tivo said otherwise...not sure the post..will research it when time permits

holl_ands

06-26-06, 04:47 PM

It would be impractical to implement at present. A lot of cable companies still use lowpass filters to separate their Basic from itheir deluxe or enhanced basic, so there is no available room below the lowpass point for them in such systems at present.
Here is FCC Factsheet re "Tier Buy Through" as prescibed BY LAW in the 1992 Cable Act:
http://www.fcc.gov/mb/facts/DOC-231469A1.pdf

1. Local broadcast channels are required to be carried on Basic Cable. [DTV are local broadcast channels.]

2. Basic Cable is the ONLY prerequisite for subscribing to programs available on either a "per channel" or "per event" basic, specifically identified as Premium (e.g. HBO, SHO/TMC, STARZ, CMAX, Playboy) or Pay Per View channels and is to include the entire Multiplex of associated Premium channels (that's over 3 dozen channels for us).

For TWC-SD, it takes 13 QAM channels to carry all of the qualifying and Premium "per channel" multiplexes plus 2 more for Local HD. (Although they could consolidate it into maybe 10 channels total.) At least a few more QAM carriers would be needed for qualifying PPV channels, Cable Modem and VoIP Phone service.

It is conceivable that some of the smaller MSOs have chosen to fit a few--perhaps as many as a dozen--QAM channels into a "gap" betwen Basic Cable and an "Expanded" tier. It would be obvious simply by looking at their channel lineup--there would be a big gap between Basic and "Expanded" channel numbers. However, I doubt that there are more than a handful of systems that have taken this approach.

But certainly not COMCAST, TWC, COX, etc. with their large number of analog and Premium Multiplex choices...plus PPV, OnDemand, VoIP and Cable Modems...

The cable operator would need to use Band Reject Filters to deny access to the "Expanded Tier", such as the fol. BRF-222-526 example:
http://www.soontai.com/BRF.html

Like most MSOs, we have a total of 71-75 analog channels. QAM digital carriers are on higher channels. [BTW: on TWC-SD, two QAM carriers on 91 and 97 MHz (mosty Hispanic tier) are in the "FM Gap".]

So a simple LPF to roll-off "Expanded" cable (and above) simply isn't feasible in modern digital cable systems....it would also roll off access to the Premium Multiplexes, PPV, Cable Modems and VoIP.

So if they erroneously installed an antique LPF filter left over from the '70s, have your MSO replace it with a more modern Band Reject Tier Filter.

sregener

06-26-06, 06:59 PM

Here is FCC Factsheet re "Tier Buy Through" as prescibed BY LAW in the 1992 Cable Act:
http://www.fcc.gov/mb/facts/DOC-231469A1.pdf

1. Local broadcast channels are required to be carried on Basic Cable. [DTV are local broadcast channels.]

Time and again, the FCC has said that digital television is *NOT* covered by the same terms and conditions as analog. You are inferring from this document that digital television is considered legally to be "local broadcast channels." The reasoning behind this is that requiring both would be to require double carriage of broadcast programming - once in analog and once in digital - without any just compensation due to the cable company for the lost bandwidth should local stations invoke "must carry."

Charter Communications does not include HD locals in their basic package, at least in my area. They require a digital subscription in order to receive those channels. If they were in violation of FCC law, something would have been done about this before now. As it is, they've done this for over a year with no response from the FCC.

Neil L

06-26-06, 09:01 PM

The FCC does require that the cable company provide a cablecard if you request it instead of an HD set top box. That should save a few bucks if you have a TV with a cablecard slot.Well, I don't. I only have a PC card that will tune QAM. I don't mind spending the money for premium channels if I want them. But I am against spending extra money for channels that I can get OTA.
So if they erroneously installed an antique LPF filter left over from the '70s, have your MSO replace it with a more modern Band Reject Tier Filter.That isn't the case. They do carry one (1) clear QAM channel. I didn't mention it earlier because it is NOT HD. It is the 24/7 weather sub channel from the local ABC station. But they encrypt the main HDTV channel from this same local station. I get this channel fine with my antenna. It's all the other networks that are 70 plus miles away that I would like to get from cable, as my OTA reception is not reliable. The local cable co carries all those distant (analog) station, but only about half of them are available even if you pay for the HD package. Granted the HDTV package does include some premium content, ESPN-HD, Discovery HD, a movie channel or two, etc. All I really want is the OTA networks HD content via clear QAM.
the FCC has said that digital television is *NOT* covered by the same terms and conditions as analogI've read several pages of FFC rules , regulations and definitions, and what you said, is the way it looks to me also. Cable "must carry" only one version of a local broadcast on basic cable. And the one my local company chooses to carry is the analog.

holl_ands

06-26-06, 11:08 PM

Time and again, the FCC has said that digital television is *NOT* covered by the same terms and conditions as analog. You are inferring from this document that digital television is considered legally to be "local broadcast channels." The reasoning behind this is that requiring both would be to require double carriage of broadcast programming - once in analog and once in digital - without any just compensation due to the cable company for the lost bandwidth should local stations invoke "must carry."

Charter Communications does not include HD locals in their basic package, at least in my area. They require a digital subscription in order to receive those channels. If they were in violation of FCC law, something would have been done about this before now. As it is, they've done this for over a year with no response from the FCC.
Nothing is simple....let me know if my understanding of the fol isn't accurate/complete....

In Feb 2001, the FCC did not endorse Dual Must Carry rules released in a Jan 2001 "Report and Order", reportedly because they were "ambiguous" (maybe unconstitutional) and hence MSOs are NOT required to carry both analog and digital versions of local channels that elect the "Must Carry" rule.
http://www.gacable.com/images/Digital-Must-Carry-2005.pdf
However, the FCC did endorse the Simplex Digital Must Carry rule for digital only stations.
And "Low Power" stations apparently never had digital Must Carry but want it:
http://www.broadcastingcable.com/article/CA6346147.html

The FCC put off--again--the meeting to re-address "Must Carry" rules for local digital multicast signals---reportedly to allow time for it to be addressed in Congress (along with Broadcast Flag, et.al.)---but also cuz they didn't have the "right" concensus---so stay tuned:
http://www.multichannel.com/article/CA6340640.html

=========================================
BUT, we mustn't get too wrapped up in the brou-haha re mandatory "Must Carry" rules.

I've read that most local stations are using "Retransmission Consent" instead--which means it's whatever agreements the local station, local MSOs and franchise entities negotiate into a contract....which could/should mandate that the digital version be available unencrypted as part of Basic Cable.

Here's the Title 47 LAW that mandates that local broadcast channels must remain unencrypted:
http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?type=simple;c=ecfr;cc=ecfr;sid=db0ae37ab7b3bc30d49689bde 4693ef7;idno=47;region=DIV1;q1=unencrypted;rgn=div8;view=tex t;node=47%3A4.0.1.1.4.23.3.4
§ 76.1904 Encoding rules for defined business models.
(a) Commercial audiovisual content delivered as unencrypted broadcast television shall not be encoded so as to prevent or limit copying thereof by covered products or, to constrain the resolution of the image when output from a covered product.

The wording was actually written by the MSOs and CEA as part of their voluntary Dec 2002 "Plug-and-Play Agreement" that addressed how these spiffy new digital channels are to integrated into Digital Cable Ready TVs via Navigation PODs (CableCard) and non-DCR TVs via DVI/HDMI and Firewire ports:
http://www.1394ta.org/Download/Members/FCC/Final_Filing_Package_file_stamp4.PDF
See pdf page 36 for the applicable section and pg 4 for the MSO signatures, including COMCAST.....

[Thanks to michaelscott for the links in the SA8300HD PASSPORT thread....]

=======================================================
So you have to pester the MSO supervisors to read the fine print and clarify company policy on how to order only Local HD as part of Basic Cable for your Digital Cable Ready HDTV....which of course the CEA/MSOs somehow gerrymandered onto the ATSC Tuner Mandate.

In San Diego (and elsewhere) persistent pestering has resulted in Local (mandatory unencrypted) HD channels being available with only Basic Cable on TWC and COX....but the CSRs are clueless....

In order for Cable Techs to install the "right" Tier Filter, it helps if you have (or had) a service that use a higher frequency (e.g. Cable Modem, cancelled CableCard for a Premium tier buy-through channel(s), STB on a second TV, VoIP?, et. al.)
So YMMV....check your local thread to see if others are getting unencrypted QAM to work...

BTW: On TWC-SD (and other MSOs are following suit), all analog channels are Digital Simulcast on digital QAM carriers--but they are all encrypted--go figure--so much for the "not enough capacity" argument....

Obviously, getting Local HD via cable to work may eliminate the installation/WAF hassles and partial reception problems many of us experience with HDTV Antenna(s)---bringing this post right on-topic...

JasonBrown

06-30-06, 03:50 PM

What kind of antenna would folks suggest for the following? My setup is a HR10-250 HD DVR from DirecTV*:

DTV Antenna
Type Call Sign Channel Network City State Live
Date Compass
Orientation Miles
From Frequency
Assignment
* yellow - uhf KDTN-DT 2.1 DAY DENTON TX 142° 17.5 43
* yellow - vhf WFAA-DT 8.1 ABC DALLAS TX 139° 14.5 9
* yellow - uhf KXAS-DT 5.1 NBC FORT WORTH TX 137° 14.8 41
* yellow - uhf KXTX-DT 40.1 TEL DALLAS TX 137° 14.8 40
* yellow - uhf KTXA-DT 21.1 UPN FORT WORTH TX 142° 17.5 18
* yellow - uhf KSTR-DT 49.1 UNI IRVING TX 142° 17.5 48
* yellow - uhf KUVN-DT 23.1 UNI GARLAND TX 137° 14.5 24
* yellow - uhf KDAF-DT 33.1 WB DALLAS TX 142° 17.5 32
* yellow - uhf KDFW-DT 4.1 FOX DALLAS TX 139° 14.5 35
* yellow - uhf KFWD-DT 52.1 IND FORT WORTH TX 137° 14.6 51
* green - uhf KDFI-DT 27.1 IND DALLAS TX 142° 17.5 36
* green - uhf KPXD-DT 68.1 i ARLINGTON TX 137° 14.4 42
* red - uhf KERA-DT 13.1 PBS DALLAS TX 136° 15.7 14
* red - uhf KMPX-DT 30.1 DAY DECATUR TX 49° 13.9 30
* red - uhf KTVT-DT 11.1 CBS FORT WORTH TX 136° 15.7 19
* blue - uhf KDTX-DT 58.1 TBN DALLAS TX 137° 14.5 45
* blue - uhf KLDT-DT 55.1 IND LAKE DALLAS TX 19° 18.9 54

really only interested in 8.1, 5.1, 21.1, 33.1, 4.1, 27.1, and 11.1

bobby515

06-30-06, 04:05 PM

sregener

07-02-06, 10:50 PM

What kind of antenna would folks suggest for the following?

A Channel Master 3021 (4-bay bowtie) should be perfect for your situation. Mount it on the roof if possible, though it will likely work in an attic if you're willing to fiddle with positioning to find the best spot.

sregener

07-02-06, 10:55 PM

hi first post i got a samsund hdtv lcd, hd is great reg. comcast stinks including hbo, encore, the only great picture is hd, comcast say line is good samsung said i need to live with it , is there anything i can do..

If I understand your problem, you're saying that HD looks great, but analog and SD digital stations look terrible. There are a couple reasons why this is so, and there are some things you can do, but you may never end up happy.

First of all, your new HD set has much better resolution and definition than the older NTSC sets did. It is also probably bigger than your older set was. This is great when the picture is really clear, but when there are flaws, they'll stand out because you can see everything clearly now, while it was blurred before by the limits of the old technology. There's nothing that can be done to make analog look better than it is.

However, properly adjusting your color, brightness, contrast, and the sharpness control (which should be set at zero) may make the picture look better. An overly bright/contrasty picture will look worse than it should. Sharpness actually introduces noise into the picture, and noise is made worse on exactly those things that don't belong. You can adjust these yourself using a DVD like Video Essentials, or you can pay someone who is ISF certified to come out and adjust these things and many others that the average person shouldn't try to mess with. Typically, you'd pay $20 for a DVD and get a pretty good picture, or $300 for an ISF tech and get the best picture your set can display. The choice is yours.

bobby515

07-03-06, 06:00 PM

sregener , i think what you said makes lots of sense my 3 y/o rear projection, downstairs in my living room look way better, cable company checked the line tv is 2 weeks old new samsung 4000-1 32 lcd. Channel Master 3021 will this help me with hbo non hd channels????and what kind od dvd is that and where can i buy one
bob

FranksPlace2

07-05-06, 11:17 AM

hi first post i got a samsund hdtv lcd, hd is great reg. comcast stinks including hbo, encore, the only great picture is hd, comcast say line is good samsung said i need to live with it , is there anything i can do..
bob

You can consider over-the-air signals for HDTV local channels. You need a ATSC tuner and a UHF antenna. Get antenna & signal info here:
http://antennaweb.org/aw/welcome.aspx

Frank

bobby515

07-05-06, 06:43 PM

samsung tell me that the problem will get fixed it feb. when the laws change, if i switch to a dlp rear projection will it get any better.my toshiba works great..i want to take tv back i love the hd channels, but disc, encore, all hbo non high def. play like crap about 80+channels
thanks for all the impit
bob

sregener

07-05-06, 07:20 PM

Channel Master 3021 will this help me with hbo non hd channels????and what kind od dvd is that and where can i buy one

The Channel Master 3021 is an antenna for receiving over-the-air broadcasts. It won't help with HBO unless you live in one of the few communities in the country that broadcast it.

I searched Amazon and found new and used copies, as well as "The Avia Guide to Home Theater" which some say is better.

Your cable company is wrong about 2/2009 - that won't help any of the stations that are giving you troubles.

bobby515

07-05-06, 08:52 PM

samgsung said feb 2007 the gov. will make them change, will it help me, if not would you buy a different tv...my older projection works great this is for a bedroom
thanks again bob

sregener

07-05-06, 09:09 PM

...if not would you buy a different tv...my older projection works great...

Your older projection is not HD, right? Have you gotten very close to the screen to make sure the picture looks as good as you think it does? I suspect the same image problems are there on the old set, but it's harder to see.

I would make sure the current set is configured properly before I'd get rid of it. Any television that isn't properly set up could give you trouble, and few are set up properly at the factory - they're set up for display in a store, not for viewing at home.

bobby515

07-05-06, 10:05 PM

samsung has good suport and said they cannot fix it ,its 2 weeks old, my older projection is hd with same type on hd box, the picture on hbos encores max.hbo are way better, i took first tv back last week and got the same as a replacement thinking i had a bad one
bob

texasozzie

07-06-06, 07:46 AM

I'm looking for some advice on getting an HD Antenna. Here is the AntennaWeb data for me:

AntennaType Call Sign Ch Network City Azimath Miles Freq
yellow - uhf KFTH-DT 67.1 TFA ALVIN TX 149° 13.8 36
yellow - uhf KHOU-DT 11.1 CBS HOUSTON TX 148° 14.7 31
yellow - uhf KHCW-DT 39.1 WB HOUSTON TX 147° 14.3 38
yellow - uhf KETH-DT 24.1 TBN HOUSTON TX 150° 14.4 24
yellow - uhf KAZH-DT 57.1 AZA BAYTOWN TX 149° 13.8 41
yellow - uhf KXLN-DT 45.1 UNI ROSENBERG TX 150° 14.4 46
yellow - uhf KZJL-DT 44 SAH HOUSTON TX 148° 14.9 44
yellow - uhf KTXH-DT 20.1 UPN HOUSTON TX 150° 14.4 19
yellow - uhf KNWS-DT 51.1 IND KATY TX 148° 14.7 52
yellow - uhf KTMD-DT 47.1 TEL GALVESTON TX 149° 13.8 47
yellow - uhf KTRK-DT 13.1 ABC HOUSTON TX 145° 14.1 32
yellow - uhf KTBU-DT 55.1 IND CONROE TX 150° 14.4 42
yellow - uhf KPRC-DT 2.1 NBC HOUSTON TX 147° 14.3 35
yellow - vhf KPXB-DT 49.1 i CONROE TX 149° 13.8 5
yellow - uhf KRIV-DT 26.1 FOX HOUSTON TX 145° 14.0 27
yellow - vhf KUHT-DT 8.1 PBS HOUSTON TX 145° 14.0 9
blue - uhf KBTX-DT 3.1 CBS BRYAN TX 331° 61.0 50
violet - uhf KLTJ-DT 22.1 DAY GALVESTON TX 139° 38.5 23

I live in Houston and live in a subdivision without any buildings taller than 2 stories. I hae a 2 story house and a 1 story garage in back. I have a D*TV dish on my garage that gets a good strong signal. I had to place the dish on the garage, because I had 2 large trees (over 40') blocking the southern view from the house. I have 2 HDTVs that I want to getsignal to.

So here are my questions:

1. What model antenna would work best?
2. Where should I mount the Antenna?
3. Do I need to amp the antenna signal if I split it? What length of antenna run would require amplification?

THANKS!

sregener

07-06-06, 09:43 AM

I'm looking for some advice on getting an HD Antenna.

...So here are my questions:

1. What model antenna would work best?
2. Where should I mount the Antenna?
3. Do I need to amp the antenna signal if I split it? What length of antenna run would require amplification?

1) Since all of your channels are on UHF, about 15 miles away, and within 5 degrees of each other, probably the best choice is the Channel Master 3021 (4-bay bowtie.)

2) The best place to put an antenna is always outdoors, as high as is reasonable. Indoor or attic antennas can work at your distance, but placement has to be precise, and you need a little luck to have stable reception.

3) You would not want to use an amplifier at that distance, as it would be overloaded by the strong signals. I imagine, at that distance, you'd probably need a cable run over 500 feet to really have a problem.

bobby515

07-07-06, 10:21 PM

hi sregener
if i switched to an edtv plamsa 42 '" would that be a down grade, i have read on consumer reports that on local cable some model work good, all lcd rated there for now have bad ratings for cable tv, plasma has better, mostly panasonic has the good ratings any feedback would help me thanks
bob

rlapporte

07-08-06, 05:44 AM

Konrad2

07-08-06, 12:02 PM

> I live about 20 miles outside of Chicago and was wondering what the best antenna
> would be for me for HD programming.

> I'm leaning toward locating it in my attic

In addition to avoiding a fight, the attic will protect your antenna from wind,
corrosion, etc. At the expense of less signal, perhaps a lot less if the antenna
has to "look" through metal or dense materials like brick/stone/concrete.
It's worth trying. If you don't get enough signal you can always move it
outside.

For the UHF, I'd suggest the Winegard PR-8800, assuming you have enough height
in your attic. 34"H 45"W about $40 plus shipping. Mostly aluminum, so less
weight and less problems with corrosion than steel antennas.

If you don't have the height for an 8-bay, I'd look at Yagis. The XG91 has
a good reputation.

IIRC, WBBM-DT is problematic, so see your local forum for advice.

holl_ands

07-08-06, 03:17 PM

I live about 20 miles outside of Chicago and was wondering what the best antenna would be for me for HD programming. I live in a townhouse and the association forbids outdoor antennas. From my understanding, they can't enforce it, but I don't know if I really want to battle with my neighbors, so I'm leaning toward locating it in my attic. Here is the reception in my area from anennaweb:

I assume CBS will be a problem, right?

* yellow - uhf WSNS-DT 44.1 TEL CHICAGO IL 148° 22.8 45
* yellow - uhf WXFT-DT 60.1 TFA AURORA IL 148° 22.8 59
* yellow - uhf WFLD-DT 32.1 FOX CHICAGO IL 148° 22.8 31
* yellow - uhf WCIU-DT 26.1 IND CHICAGO IL 148° 22.8 27
* yellow - uhf WCPX-DT 38.1 i CHICAGO IL 148° 22.8 43
* yellow - uhf WYCC-DT 20.1 PBS CHICAGO IL 144° 22.1 21
* yellow - uhf WTTW-DT 11.1 PBS CHICAGO IL 148° 22.8 47
* yellow - uhf WPWR-DT 50.1 UPN GARY IN 148° 22.7 51
* yellow - uhf WLS-DT 7.1 ABC CHICAGO IL 148° 22.8 52
* yellow - uhf WMAQ-DT 5.1 NBC CHICAGO IL 148° 22.8 29
* yellow - uhf WGN-DT 9.1 WB CHICAGO IL 148° 22.8 19
* yellow - uhf WGBO-DT 66.1 UNI JOLIET IL 144° 22.1 53
* green - vhf WBBM-DT 2.1 CBS CHICAGO IL 144° 22.1 3
Note:

Yellow means you should have plenty of signal for a modest (e.g. CM4221, PR4400, DB-4) UHF antenna in the attic.

Although the DB-8 and PR8800 8-Bays should also work, the CM4228 8-Bay would be a better choice since it may have enough gain in the VHF band to pick up CH2, and its design uniquely provides significant gain for the upper VHF channels when DTV channels are relocated in a couple years. [As others and I have discussed in this forum many times...]

Green means you have plenty of VHF CH3 signal--but if the CM4228 is insufficient, you should use at least a pair of rabbit ears (or a DIY folded dipole)....and a UHF/VHF Combiner for the downlead.

Since most rabbit ears don't extend out to 89 inches (2.26 m), here's how to construct a higher performance folded dipole for CH3, using twin-lead:
http://www.wfu.edu/~matthews/misc/dipole.html

However, you might want to try the CM4228 or CM4221....if necessary, first with the cheap rabbit ears....at that range I should think that most any chunk of wire would work for VHF....

bobby515

07-09-06, 11:30 AM

is edtv better then hd with are current cable problems...consumer reports says panasonic plamsas at last review had better picture under cable conections, 4 of them rated good, all others were pooor or very bad..also how id edtv on movies and hdtv channels, all options and answeres would be great
bob

Neil L

07-09-06, 02:27 PM

Bob,
You are in the Antenna forum. I think you will get more response if you ask about plasma TVs in the Plasma TV section of the forum.

Konrad2

07-11-06, 01:33 PM

LlamaLarry

07-11-06, 03:22 PM

blue - vhf WRC 4 NBC WASHINGTON DC 70° 42.2 4
blue - uhf WDCA 20 UPN WASHINGTON DC 67° 41.9 20
blue - uhf WETA 26 PBS WASHINGTON DC 68° 42.0 26
blue - vhf WUSA 9 CBS WASHINGTON DC 70° 42.6 9
blue - vhf WTTG 5 FOX WASHINGTON DC 69° 42.7 5
blue - uhf WDCW 50 WB WASHINGTON DC 70° 45.5 50
blue - vhf WJLA 7 ABC WASHINGTON DC 70° 42.6 7
* yellow - uhf WNVT-DT 30.1 IND GOLDVEIN VA 103° 17.7 30
* red - uhf WPXW-DT 66.1 i MANASSAS VA 76° 25.6 43
* violet - uhf WJLA-DT 7.1 ABC WASHINGTON DC 70° 42.6 39
* violet - uhf WTTG-DT 5.1 FOX WASHINGTON DC 69° 42.7 36
* violet - uhf WUSA-DT 9.1 CBS WASHINGTON DC 70° 42.6 34
* violet - uhf WRC-DT 4.1 NBC WASHINGTON DC 70° 42.2 48I am considering upgrading my OTA antenna but wanted to see what you guys thought. I live out in the sticks, current antenna is an unknown brand, uknown age rig that was here when I moved in 7 years ago. I have replaced the preamp with a CM 7777, replaced the balun and the external wiring. I can most of the channels listed but 5 is really iffy in the rain and 20 gives 0 signal on HR10-250 and a SIR-T451.

The house is 15 years old and I would not be the least bit surprised if the antenna were that old, or older.

House is 3 stories, mast is 5 feet above roofline, no buildings or tall trees for miles.

frozen_rope

07-11-06, 03:30 PM

Hi, what would be your suggestion for an HDTV antenna for me? I would like to integrate it into my DirecTv system with three HR10-250 receivers. I live in Delray Beach, FL in a two-story house and my antennaweb profile is as follows:

DTV Antenna
Type Call Sign Channel Network City State Live
Date Compass
Orientation Miles
From Frequency
Assignment
* yellow - uhf WSCV-DT 51.1 TEL FORT LAUDERDALE FL 196° 34.2 52
* yellow - uhf WAMI-DT 69.1 TFA HOLLYWOOD FL 196° 34.2 47
* yellow - uhf WHDT-DT 59.1 IND STUART FL 6° 17.6 59
* yellow - uhf WXEL-DT 42.1 PBS WEST PALM BEACH FL 312° 12.1 27
* yellow - vhf WPEC-DT 12.1 CBS WEST PALM BEACH FL 322° 11.0 13
* yellow - uhf WPXP-DT 67.1 i LAKE WORTH FL 322° 11.0 36
* yellow - uhf WPTV-DT 5.1 NBC WEST PALM BEACH FL 321° 11.2 55
* yellow - uhf WFGC-DT 49 CTN PALM BEACH FL FCC Ext 322° 11.0 49
* yellow - uhf WFLX-DT 29.1 FOX WEST PALM BEACH FL 312° 12.1 28
* green - uhf WTCE-DT 38.1 TBN FORT PIERCE FL 356° 38.7 38
* red - uhf WTVX-DT 34.1 UPN FORT PIERCE FL 342° 48.7 50
* red - uhf WPBF-DT 25.1 ABC WEST PALM BEACH FL 342° 48.7 16
* red - uhf WPXM-DT 35.1 i MIAMI FL 196° 34.2 26

All I really care about is the 4 major networks which are channels 5.1, 12.1, 29.1, and 25.1.

Thanks!

holl_ands

07-11-06, 04:28 PM

> Although the DB-8 and PR8800 8-Bays should also work, the CM4228 8-Bay would be
> a better choice since it may have enough gain in the VHF band to pick up CH2

CH2 ? Looks like the actual digital frequency is channel 3.

The Kerry Cozad chart shows the PR-8800 as having more gain at channels
2 and 3 than your beloved CM-4228. It also has less weight and less
wind loading, and likely less problems with rust/corrosion.

The Cozad chart doesn't have the DB-8, but they tend to be about twice as expensive,
so even if it has slightly better gain you could get 2 PR-8800 (or CM-4228)
and set up a 16 bay for the same money. Or add a seperate VHF antenna.
I fixed the CH2 "typo" the same day I posted it...I see corrected CH3 now...

Since not much of antenna should work for CH3 at short range, I would be more concerned about whether the chosen antenna would need to be replaced in a couple years when Chicago's WLS-DT goes to CH7 and CH3 may/probably moves to CH11.

SEMIJim

07-11-06, 05:42 PM

I'm about 14 miles from the cluster of towers that originate most of the analog and digital broadcasts in my area. Everything on VHF and UHF analog is pretty good, other than channel 62. The stronger DTV stations are good, but two channels are frequently so-frequently disrupted as to make them unusable. So I'm thinking of starting with a roof antenna upgrade. Here's my short list:

Channel Master 3016
Winegard HD7078P
Winegard PR-5646
Winegard PR-7010

Anybody have any opinion on the over-all quality, construction and performance of Channel Master vs. Winegard?

This http://www.rochesterhdtv.com/viewtopic.php?t=243&highlight= kind of concerned me.

Thanks!

sregener

07-11-06, 05:45 PM

Anybody have any opinion on the over-all quality, construction and performance of Channel Master vs. Winegard?

I like the Winegards a little better for build quality, and their "HD" lineup has better UHF performance than the Channel Masters, but I'm sure you'll get the opposite viewpoint from somebody else.

bobby515

07-11-06, 06:19 PM

i had a reception problem with local cable tvs
bob

SEMIJim

07-11-06, 06:36 PM

I like the Winegards a little better for build quality, and their "HD" lineup has better UHF performance than the Channel Masters,

Yes, here's the same list, with the average VHF low, VHF high and UHF gains, as well as boom length and max. width:

Channel Master 3016 - 1.2/7.9/7.7db, 66 x 84

Winegard HD7078P - 2.8/9.0/10.6db, 65 x 110

Winegard PR-5646 - 2.9/7.4/8.9db, 67 x 104

Winegard PR-7010 - 2.6/6.8/7.9db, 67 x 111
The HD7078P looks the best, but its maximum width is 3' wider than the CM!

but I'm sure you'll get the opposite viewpoint from somebody else.We shall see :)

newsposter

07-12-06, 08:52 AM

acrolect

07-12-06, 01:19 PM

Good afternoon; i'm looking at a PR-8800 for the following channels. I'm only interested in the major networks; we are literally right on the Mason Dixon line and I prefer the Pennsylvania channels (blue) 8.1, 21.1, 27.1 and 43.1; will the PR-8800 work ? Thank you

* blue - uhf WGAL-DT 8.1 NBC LANCASTER, PA 54° 30.4 58
* blue - uhf WLYH-DT 15.1 UPN LANCASTER, PA 48° 47.7 23
* blue - vhf WHP-DT 21.1 CBS HARRISBURG, PA 21° 44.1 4
* blue - uhf WPMT-DT 43.1 FOX YORK, PA 56° 30.8 47
* blue - vhf WHTM-DT 27.1 ABC HARRISBURG, PA 15° 41.5 10
* blue - uhf WGCB-DT 30.1 IND RED LION, PA 71° 26.4 30
* violet - uhf WITF-DT 33.3 PBS HARRISBURG PA 21° 44.1 36

sregener

07-12-06, 03:01 PM

Good afternoon; i'm looking at a Silver Sensor or a PR-8800 for the following channels.

To get ABC and CBS from PA, you'll need a VHF/UHF antenna, and neither of the ones you've selected are going to work.

SEMIJim

07-12-06, 10:33 PM

Called a local store that carries Channel Master and Winegard this afternoon. Guy there suggested either the Channel Master 3679 or the Winegard HD7082P. Well, the Winegard HD7078P that was already on my short list has better UHF and hi-VHF gain figures than the CM3679, and is about half the boom length. Given that the stations I want are mostly solid, save two, I suspect the HD7082P is over-kill. Besides, the guy thought I was a lot further away from the tower cluster than antennaweb and a city-to-city distance calculator says I am. So I think I'm gonna go with the Winegard HD7078P.

SEMIJim

07-13-06, 10:27 AM

sregener

07-13-06, 11:08 AM

Can anybody recommend an Internet dealer? Perhaps one that supports AVSForum?

I've had good luck with Stark Electronic and Warren Electronics.

SEMIJim

07-13-06, 11:31 AM

I've had good luck with Stark Electronic and Warren Electronics.Thanks. This Stark Electronics (http://www.starkelectronic.com/) and this Warren Electronics (http://www.warrenelectronics.com/)?

Either one an AVSForum supporter?

Konrad2

07-13-06, 11:43 AM

> Given that the stations I want are mostly solid, save two,
> I suspect the HD7082P is over-kill.

Unless you are trying to pull in signals from different
directions and thus want a wide beamwidth, I'd suggest going
with the tightest beam pattern you can find, especially
in the vertical direction. This will, in general,
correspond to higher gain. You may not need the additional
signal strength, but a tighter beam pattern means less
chance for multipath and interferrence.

> The only local Winegard dealer I've found so far that sells
> to the public doesn't stock the HD7078P and his prices are
> pretty steep on the bigger Winegard antennas. Can anybody
> recommend an Internet dealer?

solidsignal.com had the best prices I could find on the
Winegards I wanted (PR-8800 UHF and YA-1713 VHF-HI).
Be sure to include shipping charges when comparing prices
to your local dealer. The Winegards are mostly aluminum
and thus very light, but there must be a special shipping
charge for long boxes.

The VHF reception of the PR-8800 is better than I expected,
I probably could have gotten by without the YA-1713. Oh well.

holl_ands

07-13-06, 02:59 PM

Well, this ain't lookin' good. The only local Winegard dealer I've found so far that sells to the public doesn't stock the HD7078P and his prices are pretty steep on the bigger Winegard antennas. Can anybody recommend an Internet dealer? Perhaps one that supports AVSForum?
Be sure to CALL re shipping, incl. oversize charges....

From Ft Wayne, IN: http://www.summitsource.com/
From Livonia, MI: http://www.solidsignal.com/
From San Diego, CA: http://shop.willyselectronics.com/

SEMIJim

07-13-06, 10:28 PM

Only Warren and Summit have the HD7078P. Anybody know if either or both of them are AVSForum advertisers/supporters? I guess I'll call and order from one of them tomorrow.

Thanks for all the feedback, folks!

P.S.: holl_ands: Yeah, I'll keep an eye on the shipping charges. Thanks!

Konrad2

07-14-06, 08:22 PM

> I doubt that it is even physically possible to construct a 10Hz wide filter
> with its center frequency in the RF broadcast band.

If I'm reading the numbers right, old "boatanchor" $$$$$ SAs can do 30 Hz.
Maybe the newer models can do 10?

> I use a 100Khz bandwidth filter resolution

> a grade of resolution a little finer than 100 Khz would be helpful but not essential

Well, if 100 Khz is good enough, there is:

www.aaronia.de

The HF-4040 model has:
10 MHz - 4 GHz
100 kHz resolution
Accuracy base unit (typical) +/-3dB [ sounds kinda lame? ]

price: 499,95 Euro

This thing clearly isn't going to do what a serious "boatanchor" $$$$$ SA can
do, but it is cheaper and portable.

I have a couple of concerns with this unit. Is it good enough to squeak
by for things like evaluating the quality of reception, and for seek and
destroy missions against interference? Or does it need better specs?
And I suspect that some essential functionality is only available via a
binary that requires wintel. If so, that makes it useless for me.

jrnoel

07-15-06, 05:42 PM

I'm new. I am having dish netork installed next sun. 7-23. I am getting the hd package. I also am getting the local channels, but they are not availible in hd. I live in slidell, about 30 miles outside of new orleans. I ordered a channel master 4228 and it will be here wed. I was planning to put have the satilite installer install it in my attic. If it does not pick up the locals clearly in hd, how hard is it to install the pre amp cm 7777. Should i go ahead and order it now so that the satilite installer can install it also. I was wanting to wait to see how the antenna worked alone before buying the amp. Also, any thoughts on dish network. Ive never had satitile and was wondering if you really loose signals in rain and how good the picture quality is. I currently have charter.

Konrad2

07-15-06, 07:07 PM

> how hard is it to install the pre amp

With a 4228 and only 30 miles away, you probably don't need a
preamp, unless your attic walls/roof is metal or dense material
like concrete/brick/stone.

If you do need a preamp, adding one is trivial.

Set any switches as needed (e.g. FM trap). My reception is a
lot better with the FM band trapped out, your mileage may vary.

Unscrew coax "F" connector from antenna balun.

Screw into output of preamp instead.

Connect a short length of coax from the antenna balun
to the preamp input. (RG6 quad shield recommended,
Lowes has this with waterproof weatherproof connections)

In a similar manner, add the power supply "downstream"
of the preamp.

If you have AC power in your attic you can put the power supply
up there. Otherwise put it downstairs.

One thing you need to watch out for is that some devices
like splitters may not pass the DC power up to the preamp.
If your splitters say "power pass" or something similar you
should be okay. Otherwise, you need to put the power supply
on the preamp side of any device that doesn't pass DC. Or
you can replace the device with one that does pass DC, if
possible.

If you get a model of preamp with 300 Ohm inputs instead
of the 75 Ohm coax input, you would remove the balun,
and connect the antenna to the preamp with a short length
of twinlead instead of using coax.

jrnoel

07-15-06, 07:26 PM

thanks for your help

Dan Kolton

07-18-06, 10:32 AM

JasonATL

07-18-06, 12:14 PM

I've posted before about my problems with wind when there are leaves on the trees. I've finally purchased a CM4221 and installed it in the attic as several have recommended. I find the only difference compared to using either a Silver Sensor or a "rabbit ears" loop on top of the TV is that there is a slightly higher signal strength or quality indicated on my LG3410a meter. The picture is no less prone to going away when the wind blows (even at very low speed). The meter reading drops from between the two "O"s in "GOOD" to the "B" in "BAD". I'm sure someone will recommend that I move the 4221 outside, but that's a lot of work, and I fail to see how this will improve the situation when I almost can't see any clear sky through the trees, and signal strength seems not to be any problem whatsoever when the weather is calm. Does anyone have another suggestion?

You could try a good pre-amp. By "good," I mean, for example, a Channel Master CM 7777 Titan2. The trouble is, you have a multipath problem that may or may not go away if you clean up the signal. Don't bother with a signal amplifier.

Going outside is definitely changing the situation and very likely to improve it. On a windy day, just take the antenna outside (not on the roof) and try it. See if you have the same problem. The higher you go, the better to get a clearer view of the antennas.

Do you have more height in your attic? In my old attic installation, it mattered WHERE within the attic it was, include height.

Konrad2

07-18-06, 12:15 PM

> I'm sure someone will recommend that I move the 4221 outside, but that's
> a lot of work, and I fail to see how this will improve the situation when
> I almost can't see any clear sky through the trees, and signal strength
> seems not to be any problem whatsoever when the weather is calm.

I've read that the antenna needs to be about 10 feet above the trees.
If the trees are very tall that might be impractical.

Have you tried aiming your antenna up above the trees? If you can get
enough signal that way, it might be less affected by the wind.

From http://www.avsforum.com/avs-vb/archive/index.php/t-381623-p-8.html

>} Generally speaking, leaves will attenuate signals, especially UHF,
>} and if they are being blown by the wind, this attenuation is usually
>} too variable for the automatic gain control module in your tuner to
>} compensate for.

Do you know what tuner (RF front end) and demodulator your LG3410a has?
A unit with a different RF front end and/or different demodulator
might have better luck. Unfortunately, I haven't seen any tests of the
AGC in the test reports I've read.

Has anyone seen tests of AGC performance?

Speaking of tests, has anyone seen any tests of the Thomson DTT7611
and/or the Zoran/Oren OR51132 ?

I also have a problem with variable reception quality, and wind in the trees
was a prime suspect. But the thing that has helped the most is trapping out
the FM band. I'd like to try filtering out the other non-TV frequencies,
but I haven't found a source of filters with the right frequencies for OTA.

wilchrist

07-18-06, 12:38 PM

sregener

07-18-06, 12:56 PM

I'm sure someone will recommend that I move the 4221 outside, but that's a lot of work, and I fail to see how this will improve the situation when I almost can't see any clear sky through the trees, and signal strength seems not to be any problem whatsoever when the weather is calm.

Let's say that the signal you're getting right now, on a calm day, is good enough for reception by 10dBmv. Now, if the trees blow and block the path, let's say they reduce the signal by 20dBmv. And let's say that the attic roof materials are blocking 50dBmv. (All of these are hypothetical numbers - it doesn't matter what they really are to get the gist of the point.) Now if you move your antenna outdoors, you're getting 60dBmv on a good day, but on a windy day the signal only drops to 40dBmv above your necessary level, meaning reception stays solid. That's how moving your antenna outdoors could help.

On windy days, does the signal meter jump around a lot, or does it just drop down into the Bad range and stay there?

Konrad2

07-18-06, 02:01 PM

>> The meter reading drops from between the two "O"s in "GOOD" to the "B" in "BAD".

Do we know if the LG3410a meter is signal strength, or signal quality?
I suspect it is signal quality.

I believe the theory is not that the wind reduces the signal strength,
but that it makes the signal strength change rapidly, and the AGC is
not fast enough to smooth it out.

If so, adding an amplifier seems unlikely to help. Moving the antenna
outside might help, especially if it is higher. But I wouldn't count
on it helping enough, unless you get the antenna above the trees.

Tuners have a wide range of acceptable static signal strength, thanks to
the AGC. A lab test of the "5th gen Zenith" (presumably the LG3303 chip)
found a range of 76.1 dB.

You can test how much static signal strength margin you have by adding
attenuators on a good (no wind) day.

> Now, if the trees blow and block the path

The wind could just as easily blow trees *out* of the path.
Has anyone ever heard of wind in the trees *helping* reception?

holl_ands

07-18-06, 02:55 PM

hello

i have and old 1050's style antenna on my rooftop that ive never used. recently i hooked it up to an atcs tuner in a 32d46. my main question is if anyone has ever seen this adapter that the main line is connected to. i can pick up one digital channel (not well at all). maybe the ancient adapter im using is the problem. im not sure how to describe it. there old style coaxial running into the house, then there is a white box with serated tension screws that the outside of the line is tightened into until wire is met. then there are uhf/vhf wires coming out of the box, then another adapter for rf coax conversion. its pretty old, guess my main question is do they still make them, or maybe something better?

thanks
wil
An antique antenna system can suffer death by a thousand cuts.
The antenna elements may no longer make good connections.
It sounds like you have problematic "twinlead" (about 1/2-in wide flat wires) from the antenna to an rf coax converter (a "balun" transformer). These will all degrade from moisture getting into micro-fracturers. Old coax can also degrade from moisture leaking in via old corroded connectors. Each and every connection will degrade from corrosion and should be replaced. Do I need to go on???? You know where this is headed....

If the antenna looks serviceable, you can start by replacing everything between the coax and the antenna, making sure you redo the coax connector (cut back as much as possible to replace with new coax). Run coax all the way to the antenna and attach to the antenna using a Balun Transformer, such as the fol:
http://www.radioshack.com/product/index.jsp?productId=2103912
http://shop4.outpost.com/product/2570351;jsessionid=KK-TzrHuaWtBjR-Grlux8A**.node2?site=sr:SEARCH:MAIN_RSLT_PG
I prefer the Channel Master Balun after measuring a lower loss.

If you are more than about 10-15 miles from nearest TV station, you might want to consider adding a Preamp between the balun and the coax downlead. The CM7777 and Spartan models are for fringe (greater than 30 miles) whereas the lower gain WG models (AP-4700, AP-8700 and HDP-269) are for suburban use.

Since you didn't say where you were located (zipcode & preferably nearest cross streets), or describe (post a picture?) of your antenna, we can't comment on whether it's suitable or not....

gjvrieze

07-18-06, 03:32 PM

>
If you get a model of preamp with 300 Ohm inputs instead
of the 75 Ohm coax input, you would remove the balun,
and connect the antenna to the preamp with a short length
of twinlead instead of using coax.

Which is better a 300 ohm or 75 ohm??? I have a 300 ohm antenna and wonder which amp to get.
One other question, how important is grounding the antenna and is there a better or worse way to do it, not to loose signal. I ask as i have a brand new media center pc plugged into it and soon a hdtv

holl_ands

07-18-06, 03:50 PM

Which is better a 300 ohm or 75 ohm??? I have a 300 ohm antenna and wonder which amp to get.
It probably doesn't make any difference if comparing apples to apples with the same circuitry, except for one Preamp the 1.2 dB loss Balun is internal and for the other external.

Winegard specs are 1.2 dB lower Noise Figure for 75-ohm model, which would be lost in the external balun, making it equal to the 300-ohm model.

CM Spartan specs have same Noise Figure for both 75-ohm and 300-ohm models, but I would guess their "standard" measurement would include an external balun with the 75-ohm model, making them equal.

Just make sure you only use the high gain (CM-7777, Spartan) models well away from TV broadcast towers.

gjvrieze

07-18-06, 04:29 PM

Here is my info, so i would assume, i am far away, also i do NOT have line sight and am well below the elevation of the towers. I am mainly interested in dtv stations and not listed here is WKBT-DT which is EAST of me and sregener says i should be able to get it, and i do not so, i want to know what i should do first..
red - uhf K60DS 60 TBN ROCHESTER MN 82° 6.3 60
blue - vhf KAAL 6 ABC AUSTIN MN 229° 44.2 6
blue - uhf KSMQ-DT 15.1 PBS AUSTIN MN 185° 27.2 20
blue - uhf KXLT 47 FOX ROCHESTER MN 185° 27.2 47
blue - vhf KTTC 10 NBC ROCHESTER MN 175° 32.0 10
violet - uhf KTTC-DT 10.1 NBC ROCHESTER MN 185° 27.2 36
violet - uhf WHLA 31 PBS LA CROSSE WI 104° 56.9 31
violet - uhf WXOW 19 ABC LA CROSSE WI 104° 56.9 19
violet - uhf WLAX 25 FOX LA CROSSE WI 104° 56.7 25
violet - uhf KYIN 24 PBS MASON CITY IA 200° 49.2 24
violet - vhf KIMT 3 CBS MASON CITY IA 200° 49.2 3
violet - uhf KSMQ 15 PBS AUSTIN MN 226° 36.4 15
violet - vhf WKBT 8 CBS LA CROSSE WI 84° 56.1 8
so which amp should i go with, right now i have a 190in radio shack style antenna which i am going to put up tonight, i do not know the brand but it looks just like the radio shack 80in that is currently in use.
thanks for info,
Garrett

sregener

07-18-06, 04:40 PM

Here is my info, so i would assume, i am far away, also i do NOT have line sight and am well below the elevation of the towers.

I'm in about the same location and have a 28dB UHF preamp that I use to great effect. I recommend the Winegards simply because they don't overload as quickly as the Channel Masters.

gjvrieze

07-18-06, 04:48 PM

Also do you use a 300ohm or 75ohm? I just want to make sure whatever i buy works, i had a radio shack and it killed my signal completely, and i used a new antenna and wires and properly connected.

AntAltMike

07-18-06, 06:41 PM

It probably doesn't make any difference if comparing apples to apples with the same circuitry, except for one Preamp the 1.2 dB loss Balun is internal and for the other external.

Winegard specs are 1.2 dB lower Noise Figure for 75-ohm model, which would be lost in the external balun, making it equal to the 300-ohm model.

CM Spartan specs have same Noise Figure for both 75-ohm and 300-ohm models, but I would guess their "standard" measurement would include an external balun with the 75-ohm model, making them equal.

Do they still have internal baluns? I would think that some versions of integrated circuit amplifiers would have inverting and non-inverting inputs that could be configured to develop a natural, 300 ohm load, and so they wouldn't need a high loss balun to match the line and source impedance with the load impedance.

holl_ands

07-18-06, 08:26 PM

CM uses internal Baluns on each of the VHF and UHF 300-ohm inputs, as shown in this picture showing the multi-purpose CM Spartan Circuit Board. The circuit board is populated as necessary for the different model numbers.

PinkSplice

07-19-06, 01:24 AM

Just make sure you only use the high gain (CM-7777, Spartan) models well away from TV broadcast towers.

Indeed. I'm within 3 miles of the Shrewsbury antenna farm in STL, and I need FM traps on my teeth... :(

newsposter

07-19-06, 08:36 AM

dan i'm curious..how far away are the trees? My installer said i may have problems since he installed in January and no leaves up, but i had a very very difficult 'tunnel' to see thru between my neighbors house and some unknown far off object so had to have it exactly where it was. His tree is about 200 ft away from my house and the DB8 is literally facing right at it. But i have zero problems. I guess the signal is going' around' the tree or something :)

Dan Kolton

07-19-06, 09:52 AM

There is no possible way short of a chain saw to get away from or above the trees. In earlier posts I've described setting the antenna outside at ground level. The bad behavior didn't change at all compared to any other position in the house (including the attic). I understand the building material attenuaton argument, but why then would the signal be the same whether I'm inside or outside or at ground level or in the attic? When calm day signal is almost at the top of the meter, I have trouble believing that going outside would help. At the moment, it's all academic, because it's far too hot for me to crawl up into the attic to move the antenna anywhere.

newsposter

07-19-06, 03:26 PM

50ft away...zoinks....I have no experience that close......and the signal could be the same in and out...I had high 80s for some channels with my hdtivo in the attic and still only get about the same outside...however...i got a more stable signal with little fluctuation PLUS a few more stations I didnt get before.

Also horizontal sometimes does matter. I put over ..gosh i forget..maybe 25+ hours into it myself and then paid 400 for someone else to do more to find the perfect signal. Free tv aint cheap

sregener

07-19-06, 04:30 PM

I understand the building material attenuaton argument, but why then would the signal be the same whether I'm inside or outside or at ground level or in the attic?

Because your signal meter doesn't measure signal strength but signal quality - in other words, the error ratio of your signal. That can stay the same even with signals 20x stronger (or weaker.) What makes digital reception work isn't the absolute strength of the signal (although there is a minimum and a maximum in which it can work) but the quality of that signal, how clean it is.

Brian.Leveille

07-20-06, 06:54 PM

All,

So I was happy the past few days with my reception.

Until last night.

The t-storms we had last night must have done something to my antenna install. I am no longer receiving about half the stations I was a couple of days ago.

I did a quick visual inspection from the ground, and it looks like the antenna hasn't moved or been broken.

I know that I did not waterproof my connections. Could water be a problem? Could it have seeped into the F connectors somehow and be 'shorting' something out?

Somewhat frustrated,

-BL

jrnoel

07-20-06, 10:44 PM

I'm new and have a couple of questions. I am having Dish network hd package installed sunday. 1. If I'm putting an ota in my attic do I need to ground it? 2. If I use a diplexer for the ota and the satilite, do I loose any picture quality. I am only worried about hd channels. Is there any difference in brands of diplexers or certain diplexers for hd channels?

Dan Kolton

07-21-06, 03:47 PM

sregener,

Please note: I've posted several times that I've tried both the CM4221 and the Silver Sensor out of doors in several locations, but at ground level. The results were no improvement over any indoor (including attic) location that I've tried. Picture is wonderful with no wind and useless with wind. I will try the 4221 up higher outside when I figure out a reasonable way, but I'll be extremely surprised if this solves the problem.

SEMIJim

07-22-06, 12:01 AM

I know that I did not waterproof my connections. Could water be a problem? Could it have seeped into the F connectors somehow and be 'shorting' something out?Could be. You should always weatherproof electrical connections. Wet electrical connections tend not to work so well. If the weather dries out for a few days and things improve again, odds are that was the problem. If this is the problem, and you fail to address it, those connections will steadily degrade over time. (I just replaced my roof antenna. The F-connector connection to the balun was booted and taped. Upon disassembly I found it as clean, bright and tight as the day I put it together--14 years ago :).)

Could also be that you didn't properly secure the coax, wind whipped it around, and the connections are no longer mechanically sound.

Could also be there was a very close lightning hit and your receiver was damaged.

sregener

07-23-06, 08:10 PM

sregener,

Please note: I've posted several times that I've tried both the CM4221 and the Silver Sensor out of doors in several locations, but at ground level.

Antenna height is critical - I got nothing at ground level, but a good signal at 22' outdoors. If I had to choose between ground level outdoors, and attic level indoors, I'd always pick attic level.

newsposter

07-24-06, 02:45 PM

Antenna height is critical - I got nothing at ground level, but a good signal at 22' outdoors. If I had to choose between ground level outdoors, and attic level indoors, I'd always pick attic level.

Since i have personal experience I need to say higher is not 'always' better. (maybe 99.9%, but not always) The guy installed my DB8 10ft up off the chimney. signal sucked and he had to come back out because my difficult station was still being difficult.

lowered it to a 2 ft tripod about 10 ft down the roof, came in fine every since then. I admit to having a very very difficult setup shooting past a neighbors house and some other unknown object. But just wanted to remind people that nothing is absolute in the antenna world (except if he stands in front of the antenna i get no signal :)) and horizontal can pay off too.

gjvrieze

07-24-06, 03:49 PM

I may not have near the experience that sregener has, but i know from the past few months, that no two installs are the same, it is always different from home to home... BUt i have also noticed that height is very important...

Neil L

07-24-06, 05:55 PM

installed my DB8 10ft up off the chimney. signal sucked. lowered it to a 2 ft tripod about 10 ft down the roof, came in fine every since then. I admit to having a very very difficult setup shooting past a neighbors house and some other unknown object.Yes, finding the signal "hot spot" can do wonders for reception. But, by going lower your installer had to look for a hot spot. If you go higher, above the obstructions, you are more likely to find a good signal with less critical positioning.

So you can't really say lower was better, even in your difficult situation. Lower just happened to work, where higher might have worked as well, or even better. Albeit, there is probably much more expense involved in going higher.

Dan Kolton

07-25-06, 09:56 AM

Last night, I was able to get a more stable signal using the Silver Sensor atop my set than using the CM4221 in my attic. There was only a slight breeze; neither antenna gave a reliable picture and I ended up watching analogue (which was also of variable quality, but didn't completely lose either picture or sound).

newsposter

07-25-06, 07:47 PM

So you can't really say lower was better, even in your difficult situation. Lower just happened to work, where higher might have worked as well, or even better. Albeit, there is probably much more expense involved in going higher.

lower was better than the higher position easily available to me..how's that?

SEMIJim

07-25-06, 10:21 PM

lower was better than the higher position easily available to me..how's that?You're comparing apples and oranges: He moved the antenna 10 feet over. For an apples:apples comparison, you'd have to compare the antenna at the different heights in the same locations. Now it may be that lowering the antenna in the original location might not have made things any worse. And it might be that raising the antenna in the new location wouldn't make things any better. But comparing the two heights at different locations proves nothing other than it worked better in the latter location.

JasonBrown

07-26-06, 09:52 AM

goldrich

07-26-06, 10:58 AM

I have a Zenith Silver Sensor and get around 85-90 signal strength on all my stations in the UHF band. ABC HD is a VHF frequency, in the location as the others (12 miles, due south basically) and I'm not able to get a good signal for that one in my media room (I get signal strength in the 70s in the living room though). Is there a way I can piggyback a pair of rabbit ears to the SilverSensor in an attempt to get the VHF feed?

You could join the two together using something like this.....
http://www.starkelectronic.com/cmjoiner.htm Use the 0549 if you are not using a preamp, and use the 0538 if you are using a preamp on the line.

Steve

jtbell

07-26-06, 11:01 AM

You need a "joiner", like one of the ones on the page linked below. Your setup is indoors, so the CM 7207 looks like a good match. You can probably find something similar at Radio Shack, but I can't find anything quickly in their online catalog.

http://www.warrenelectronics.com/Antennas/joiners.htm

newsposter

07-27-06, 07:36 AM

You're comparing apples and oranges: He moved the antenna 10 feet over. For an apples:apples comparison, you'd have to compare the antenna at the different heights in the same locations. Now it may be that lowering the antenna in the original location might not have made things any worse. And it might be that raising the antenna in the new location wouldn't make things any better. But comparing the two heights at different locations proves nothing other than it worked better in the latter location.

didnt you just prove my point that higher is not always necessarily better ? ;) Each location must be evaluated individually.

iLLWiLL

07-27-06, 05:12 PM

I am within 20 miles of all transmitters (UHF), which are all pointing in the same direction.

I bought this RCA antenna (http://www.bestbuy.com/site/olspage.jsp?skuId=7367896&type=product&productCategoryId=cat08084&id=1122653825071) from Best Buy. But I have issues such as the signal breaking up occasionally. On most stations, I'll fluctuate from about 88% to 100%. But sometimes I will spike down to 0% (which obviously is causing the signal to break up).

Is there a better [indoor] antenna out there that I can buy? At a reasonable price? I've seen some people in this forum say they maintain a 100% signal.( :confused: )

Any suggestions? Thanks! :)

rgoodwin

07-27-06, 06:03 PM

This is why I never throw anything away :) I just got into OTA HDTV and needed a "balun" and had no clue what it was....

Thanks to Google I found a picture and sure enough I had not one but two in my junk drawer including a 2100B that I have NO clue the source of.

Anyway, thought it was amusing and it's so quick to reply... :)

In DR_LaRRY_PEpPeR's post, he provided link to my comparison test:
http://hdtv.forsandiego.com/messages/1/2489.html
Note that the maximum loss value for the CM balun was much less than any of the other outdoor baluns.

Of the baluns at hand for testing, the one with the lowest loss was actually the RMS CA-2100B, intended for indoor use.
Feel free to post any comparison results of your own....there isn't much to be found on this subject.

FYI: Here are results posted in hdtvprimer for CM0090 and two R-S balun models
and the (extremely high loss) found in the KYES test for a back-to-back Philmore/Pfantone combination:
http://www.hdtvprimer.com/ANTENNAS/basics.html
http://www.kyes.com/antenna/balun.html

sregener

07-28-06, 08:16 AM

Is there a better [indoor] antenna out there that I can buy?

Zenith Silver Sensor or Terk HDTVi.

ST RICH

07-28-06, 10:56 AM

Should I replace my current RG-59 cable with the new Quad Shield RG-6 cable?

My situation -> I have an attic configuration. I have two 12 feet RG-59 cables from a CM 4228 and a CM 4221 combine with a splitter in reverse into a Channel Master in line amplifier splitter. I have 4 lines (RG-59 - 50 feet) coming out of the splitter into my HDTVs and DVRs. There are two digital stations that I can not lock onto.

Will I get enhanced picture quality or will I be able to lock onto the stations (by reducing the line loss) with the new cables? Any opinions will be accepted. Thanks in advance...

newsposter

07-28-06, 10:56 AM

I've seen some people in this forum say they maintain a 100% signal.( :confused: )

Any suggestions? Thanks! :)

I can't help you choose one but will tell you, 100% isn't that important. my most difficult station only has about 65- 75 but it's rock solid. Stability is more important that a high meter reading.

sregener

07-28-06, 11:25 AM

My situation -> I have an attic configuration. I have two 12 feet RG-59 cables from a CM 4228 and a CM 4221 combine with a splitter in reverse into a Channel Master in line amplifier splitter. I have 4 lines (RG-59 - 50 feet) coming out of the splitter into my HDTVs and DVRs. There are two digital stations that I can not lock onto.

Will I get enhanced picture quality or will I be able to lock onto the stations (by reducing the line loss) with the new cables? Any opinions will be accepted. Thanks in advance...

I'm assuming that your two antennas are pointed in different directions. Even if they aren't, the odds are against you having the antennas in phase. What that means is that you're creating multipath with the second antenna. This is probably why you're not able to lock onto two stations. It has nothing to do with your cables.

Picture quality is not enhanced for digital reception - either you get a perfect, breakup-free picture, or you don't. There really isn't much in between.

If you did decide to replace cables, double-shielded is all you'd really need.

ST RICH

07-28-06, 12:12 PM

I'm assuming that your two antennas are pointed in different directions. If you did decide to replace cables, double-shielded is all you'd really need.

Thanks for the response. You are correct about the antennas are in direct directions. One is point east towards Baton Rouge to pick up the NBC station (I do not have a local NBC station). The FOX and ABC local stations are picked up by the same antenna. I can not pick up the local PBS and CBS stations without the extra antenna. The second antenna is pointed northwest. If I remove the second antenna and the splitter, I pick up the two stations in questioned (FOX and WB) without trouble. I understand that I loss about 3.5 db due to the splitter. I was wondering if I could gain it back with a better cable, but I do not want to waste money if the cables will not gain the 3.5 db loss back. Thanks again...

sregener

07-28-06, 12:26 PM

If I remove the second antenna and the splitter, I pick up the two stations in questioned (FOX and WB) without trouble. I understand that I loss about 3.5 db due to the splitter. I was wondering if I could gain it back with a better cable, but I do not want to waste money if the cables will not gain the 3.5 db loss back.

You're using the splitter in reverse, so there isn't 3.5dB of loss - more like 0.5dB of loss. And loss isn't your problem - multipath is, multipath you are creating by using two antennas pointed in two different directions that are both picking up signals on the same frequency. You would do better to invest in a remote A/B switch to switch between the two antennas instead of the splitter, or look into filtering if you absolutely must get all the channels at once.

SEMIJim

07-28-06, 01:12 PM

I am within 20 miles of all transmitters (UHF), which are all pointing in the same direction.One imagines you mean they're all on roughly the same bearing from your location :).

I've seen some people in this forum say they maintain a 100% signal.( :confused: )Yeah, and if they're doing it with an indoor antenna, they're certainly not 20 miles away from the broadcast towers. The signal strength (the real signal strength, not some randomly-based number a TV or radio comes up displays on its meter) of a radio wave decreases with the square of the distance. E.g.: If you're 2 miles further away than somebody else, you see 1/4 the power they do.

Kolchak

07-28-06, 07:58 PM

Thanks for the response. You are correct about the antennas are in direct directions. One is point east towards Baton Rouge to pick up the NBC station (I do not have a local NBC station). The FOX and ABC local stations are picked up by the same antenna. I can not pick up the local PBS and CBS stations without the extra antenna. The second antenna is pointed northwest. If I remove the second antenna and the splitter, I pick up the two stations in questioned (FOX and WB) without trouble. I understand that I loss about 3.5 db due to the splitter. I was wondering if I could gain it back with a better cable, but I do not want to waste money if the cables will not gain the 3.5 db loss back. Thanks again...

As sregener stated, the problem is multipath. In the past I have vertically stacked two CM4221 in opposing directions with success. As the lowest channel to be received was a high frequency, the vertical spacing was only 9 inches. Just a quick test, use the half wavelength for vertical spacing or full for horizontal of your lowest channel to receive. Slim possibility this may reduce your multipath as your stack may be to close together.

GLW65

07-28-06, 09:06 PM

I am having problems with digital off air tv reception and need some advise about what to do next. I live in Ohio east of Columbus. TV towers for digital channels 13 (ABC), 14 (NBC),21 (CBS),38 (PBS), 36 (Fox), and 53 (UPN) are all about 32 miles away. My biggest problem is that I am located behind a hill and trees. This winter I was able to pull in all but Ch14. Now with leaves on trees, etc. I am able to get some channels one night and not the next. I have tried a variety of things to try to get reception including moving the antenna vertically on the mast. I have a CM3021 4 bow tie antenna. Actually, I have 2 of them and have tried a various times to make a CM4228 by joining them horizontially. I can get various combinations of reception. Tonight, I am getting Ch 13 with as strong a signal as I ever get (about 70 on my H10-250 Directv receiver). I also get 53 strong. I can't get the signal on 14 to lock in and I can't get 36 to lock in. This is particularly strange since I believe that 36 and 13 broadcast from the same antenna location. I have a CM rotor and a CM7777 amplifier. Rotating the antenna does not get the channels. I am thinking about buying either a CM4228 or a yagi. My signal often jumps from 20 to 60 but won't lock in a digital signal. Does anyone have any ideas?

Kolchak

07-29-06, 12:00 AM

"Actually, I have 2 of them and have tried a various times to make a CM4228 by joining them horizontially."

Many will advise the CM4228 when obstructed by an obstacle such as a hill (increased directivity and gain). However, two of the CM4221 are easier to maneuver especially in attics where the opening often does not accommodate the larger one. ST RICH's situation is more complicated as the towers are in opposite directions. Stacking two together in the same direction yields improved gain and directivity. If attic install try vertical stacking (if space permits) and outside try horizontal. Ensure both pieces of coax are the same length to combiner to keep in phase. I am surprised how well ABC is received. Usually, one 4221 does not pick up a 213MHz signal like the 4228 with its continuous screen adding vhf gain. Also, unsure why NBC is problematic. Unless I'm mistaken, channel 14 is at full 1000kW power. Your receiver may be overloaded. The CM7777 boosts at least 26dB IIRC. Try attenuating the signal by at least 10dB.

GLW65

07-29-06, 09:31 AM

I have tried stacking the 3021 antennas both vertically and horizontally. The problem is that I get one set of channels one day and a different set the next. A couple of days ago I could not pick up Ch13 at all, but was getting 14,21 and 36 fine. I have tried joining the annenas horizontally both with wood connectors to hold them together and with metal ones. This seems to make a difference, but nothing has solved the problem yet. Without the CM7777 in place, I get very little signal and nothing will lock in.

Neil L

07-29-06, 02:05 PM

My biggest problem is that I am located behind a hill and trees. Looks like this IS your problem. Changing antennas and pre-amps is not likely to make much difference. You probably are not getting any direct signal, only defraction or reflections that spill over the hill. Thus, the inconsistent reception.

It may be that the only way to get a solid, consistent signal, is to get the antenna high enough to get a direct signal. How high would you have to go to clear the hill and trees?

I'm in a similar situation where it would take about a 100ft tower to get my CM4228 above a hill and trees. So far, I have not been willing to go to that expense to see if it would make much difference.

Another thing you could try is aiming the antenna in what might seem to be the wrong direction. If you are getting a signal coming around the hill that is stronger than what is spilling over it, you could be having multi-path issues. Experiment with aim over 180 degrees or so, and see if you can locate the direction of your best signal.

GLW65

07-29-06, 04:03 PM

Thanks guys. I am trying one last thing. I have mounted the 2 3021's on the same mast vertically. They are currently about 8 feet apart. I have some different signal strengths than I had before. I have to leave now, but on my return I will move the lower antenna up and down on the mast and see if I can get a good combination. I believe that multipath may be my primary problem as I sometimes have the signal strength jump to 70 for a second or two and then drop back down. If I have to go to a new antenna which do you think would be better, a yagi or the 4228 of something else? I would have to go way up to get higher. I currently have the top antenna about 40 feet, but would need another 60 or 80 to see over the hill.

AntAltMike

07-29-06, 04:19 PM

When you are behind a hill, the signal that bends over the hill is no longer in the horizontal plane, so as long as your mast is perfectly vertical, the signals will be hitting the upper elements on your multi-bay bowtie element stacks before they hit the lower ones, and therefore they wil not be completely in phase with one another.

You might do better with just a 4-bay bowtie tilted back just a little, or with a big sucker Yagi with a corner reflector, like a Winegard PR-9032. If you get an improvement with a 9032, then you might buy a second one and horizontally stack it.

holl_ands

07-29-06, 05:50 PM