You may have. Do you have aluminum siding ?

Nope.. Vinyl siding with wood underneath.

I have to borrow a larger ladder, so I hope to get the antenna on the roof next weekend. With my test on the deck I'm very happy with the results and hope they improve going higher.

RobM

FWIW - I have had 2 failed CM7777 Pre-Amps in the last 3 months.

I observe the termination is an open when ohming out the 75 ohm cable at the back of the television prior to insertion into the pre-amp. I verified the power supply, and it has 22Vdc.

I am just tired of climbing the tired and putting up my trusty Winegard in place of it, until I order a replacement.

I have had NO Electrical storms, yet do not understand why these keep failing on my stack.

Any ideas?

I verified the power supply, and it has 22Vdc. Any ideas ?


I assume you checked out the grounding block.

On my CM0264, I checked out the specs on the only transistor in it, and it was rated at 20VDC max. My Channel Master power supply, which looks to be the same one as yours, only puts out 18VDC at no load. So your power supply may be kicking out too much voltage, which may be great for a while for the additional gain from more voltage, but doesnt add to longevity.

So I live in a fringe area and life pretty much isn't good for OTA. But I have managed to get some.

I have a 30' mast with dual 91XG's and a YA1713 VHF-Hi going into a CM7777. Currently, I have a 95' run from the mast top to the basement of RG11, soon to be replaced by 3/4" hardline. I have a DTT900 Zenith setop box.

I have adequate reception on all of the UHF channels I want to receive. The hardline will hopefully fix an issue with WFFF-DT on UHF43, only comes in at night and has occasional hiccups in the signal.

Now back to the VHF problem. The winegard YA1713 is a decent antenna, but it just does not have enough gain on VHF 13 to receive WVNY-DT from 45 miles away. All other stations at that location come in fine and dandy.

I've looked at the Wade/Delhi antennas, and those monsters are cool, but they might be toooo much for my antenna mast.

Are there any other VHF-Hi or just CH13 yagi antennas out there with more gain than the YA1713?

Does anybody have a list of dimensions and parts so I could build one? I'm handy with tools, but not so handy with math anymore involved than a tapemeasure.

Thanks,

~ryan

According to the HDTV Primer site, the YA-1713 is particularly bad for channel 13 -- response is not flat at all and gain drops to almost nothing by the upper edge of the channel. Even the modest-size Radio Shack combos are better. A single-channel Yagi should do the trick, or you can use a combo just for VHF.

I doubt hardline will be that much better than RG-11, but if you're willing to use such extreme measures, one of those Research Communications pre-amps might be worth a try. They claim 0.4dB noise, which might do the trick on UHF 43, if there's signal receivable during the day at all.

According to the HDTV Primer site, the YA-1713 is particularly bad for channel 13 -- response is not flat at all and gain drops to almost nothing by the upper edge of the channel. Even the modest-size Radio Shack combos are better. A single-channel Yagi should do the trick, or you can use a combo just for VHF.

I doubt hardline will be that much better than RG-11, but if you're willing to use such extreme measures, one of those Research Communications pre-amps might be worth a try. They claim 0.4dB noise, which might do the trick on UHF 43, if there's signal receivable during the day at all.

I might have to look at a VHF/UHF combo with good gain for just ch 13 :-/ .... maybe that with a jointenna or just a ch 13 antenna and a jointenna.

The hardline is free for me. Just a matter of going to get it.

Looking up the specs on the RG11 installed and the 3/4" hardline to be installed, looks like I can gain a few db in the UHF area. It might not help much in the VHF. So UHF 43 should be good to go during the day, hopefully.

I'm using commscope 2285K RG11 and will have commscope 750 series P3 hardline.

Channels I'm interested in
Ch 7 is 174 Mhz
RG 11 approx loss per 100' is 1.5 db
3/4" hardline approx loss per 100' is 0.6 db
Diff is 0.9 db

Ch 13 is 210 Mhz
RG 11 approx loss per 100' is 2.0 db
3/4" hardline approx loss per 100' is 0.74 db
Diff is 1.26 db

Ch 14 is 471 Mhz
RG 11 approx loss per 100' is 2.8 db
3/4" hardline approx loss per 100' is 1.15 db
Diff is 1.65 db

Ch 22 is 519 Mhz
RG 11 approx loss per 100' is 2.9 db
3/4" hardline approx loss per 100' is 1.2 db
Diff is 1.7 db

Ch 32 is 579 Mhz
RG 11 approx loss per 100' is 3.0 db
3/4" hardline approx loss per 100' is 1.28 db
Diff is 1.72 db

Ch 43 is 645 Mhz
RG 11 approx loss per 100' is 3.7 db
3/4" hardline approx loss per 100' is 1.35 db
Diff is 2.35 db

Ch 55 is 717 Mhz
RG 11 approx loss per 100' is 4.0 db
3/4" hardline approx loss per 100' is 1.4 db
Diff is 2.6 db

Ch 60 is 747 Mhz
RG 11 approx loss per 100' is 4.25 db
3/4" hardline approx loss per 100' is 1.48 db
Diff is 2.77 db

From hdtvprimer.com

20 dB = gain factor of 100
10 dB = gain factor of 10
3 dB = gain factor of 2 (actually 1.995)
0 dB = no gain or loss
-1 dB = a 20% loss of signal
-3 dB = a 50% loss of signal
-10 dB = a 90% loss of signal

So it looks like I'll have a 20%-40% increase in signal.

As far as the research communication pre-amp goes, I'm considering it, but I may have to wait for a taxreturn and wife factor approval to get it.

~ryan

Looking up the specs on the RG11 installed and the 3/4" hardline to be installed, looks like I can gain a few db in the UHF area.

But you already have a CM7777 preamp that should make up for those losses. I wouldnt expect much from all that additional work installing the hardline.

But you already have a CM7777 preamp that should make up for those losses. I wouldnt expect much from all that additional work installing the hardline.

The pre-amp amplifies the signal at the mast head. I still have 95' of cable to the basement. There will be losses there. Almost every analog and digital channel in my area starts out at a negative noise margin.

Hardline is solid aluminum shield and suitable for direct burial, so it's not that much work to dig a trench 12" deep. I already have conduit out there, but it's only 1.5", so it won't pull very well through it. But the RG11 will feed a new FM antenna so my Wife can listen to some Canadian radio.

But again, my biggest problem is VHF channel 13. The cost of the wade units are quite high, and that's if they even have them in stock.

Blonder Tongue isn't much better in that price range.

The YA1713 works fine for the other channels, just not 13. Does anybody know where I can get a sub-$150 channel cut antenna with decent gain?

Or what I would need to do to build one?

Thanks,

~ryan

The pre-amp amplifies the signal at the mast head. I still have 95' of cable to the basement. There will be losses there. Almost every analog and digital channel in my area starts out at a negative noise margin.

Hardline is solid aluminum shield and suitable for direct burial, so it's not that much work to dig a trench 12" deep. I already have conduit out there, but it's only 1.5", so it won't pull very well through it. But the RG11 will feed a new FM antenna so my Wife can listen to some Canadian radio.

But again, my biggest problem is VHF channel 13. The cost of the wade units are quite high, and that's if they even have them in stock.

Blonder Tongue isn't much better in that price range.

The YA1713 works fine for the other channels, just not 13. Does anybody know where I can get a sub-$150 channel cut antenna with decent gain?

Or what I would need to do to build one?

Thanks,

~ryan

I have 3 of the big psp.1922 highbanders remaining.They do well on 13,about 2-3db better gain than the YA10-7-13.PM me if you want one.

Pic courtesy of cpcat (top antenna)

http://www.avsforum.com/avs-vb/attachment.php?attachmentid=35151&d=1111454199

I have 3 of the big psp.1922 highbanders remaining.They do well on 13,about 2-3db better gain than the YA10-7-13.PM me if you want one.

Pic courtesy of cpcat (top antenna)

http://www.avsforum.com/avs-vb/attachment.php?attachmentid=35151&d=1111454199

Wow, 156" and 174 - 230 Mhz. Perfect for VHF-Hi with an average gain of 14 db. That's similar to the gain specs of the 91XG. This is about 3 - 4 db higher gain than the winegard.

Sent you a PM.

Thanks!

~ryan

For the last 4 weeks, my parents have been using a Radio Shack 15-1878 to pick up the top 6 channels at their apartment as listed in the tvfool printout. (Their apartment is in a complex and there's a highway noise barrier close by.)

Used trial and error to get it to work...TV tuner doesn't show signal strength.

The hardest to get is WKBW and it worked great until it didn't come in last night and my father "adjusted" the antenna and really screwed it royal!

Thanks!!

We find that the circular part of the antenna works best when it lays almost horizontal with the table it's on.

I've been following this thread for 2 months but I'm totally lost! Should I try to add a 2nd antenna just to get WKBW or replace the 15-1878??? (Outdoor antenna is not a possibility)




Try one of the new RCA "Flat hangs on wall" HDTV antennas from Walmart $14.88. Hang it high on the wall; experiment with different locations. Point it towards Colden. Use 12' black Philips RG6 cable also from Walmart.

Try one of the new RCA "Flat hangs on wall" HDTV antennas from Walmart $14.88. Hang it high on the wall; experiment with different locations. Point it towards Colden. Use 12' black Philips RG6 cable also from Walmart.

Craziest thing happened....I inserted an A/B switch that I had just in case my parents wanted to watch any of their 12 cable channels they get with their $9/month lifeline cable plan.

Instantly the reception on their Radio Shack 15-1878 improved 100%.

Haven't had to do anything since, other than a very minor adjustment to the rabbit ears on occasion.

To make myself more clear.

Solid copper coax is recommended when passing voltage from point A to point B in the system. I have seen instances where the preamp seemed to have failed but in actuallity it did not. replacing the coax with solid copper fixed the problem. I recently encountered this problem even with a winegard preamp. replaced the coax and everything worked fine. The owner thought he purchased solid copper from radio shack, loews (not sure) and it was not.

The other thing to check for is a short...braid to center conductor, poorly seated fitting, corrosion, water ingress, etc.

You are getting bad information if you read or think that the coax does not make a difference. It does especially in this case..
There appears to be RG6 with solid copper, solid copper covered steel,
copper clad steel and even copper clad aluminum:
http://www.twacomm.com/catalog/sort_PART/jmp_CommScope+-+Uniprise/product_brand.htm

The shield braid can also be either copper, steel or aluminum.

And then there is the optional aluminized mylar foil for 100% double shield.

Can you be a little more specific???

FWIW - I have had 2 failed CM7777 Pre-Amps in the last 3 months.

I observe the termination is an open when ohming out the 75 ohm cable at the back of the television prior to insertion into the pre-amp. I verified the power supply, and it has 22Vdc.

Any ideas?

Have you varified what the voltage is at the preamp end of the coax?
If you have a long run of rg6 with a copper clad steel core you may be getting a voltage drop large enough to cause problems do to the poor conductive properties of steel compared to copper. Since RF rides on the skin of the conductor the copper flashing is good enough for the TV signal but the DC current needed to power the preamp could suffer from the losses in the steel core. That is the reason why it has been suggested that you use solid copper core.

All that being said if you do have a low voltage problem I don't think that it will damage the preamp, electronics is very rarely damaged by low voltage.

Have you checked them out once you have taken them down?

Have you varified what the voltage is at the preamp end of the coax?

Good point, Ill have to check out and note my voltage at the preamp end and note it for future reference.

But from what PCTools wrote, it looks like he may have too high of a voltage going to it.

Thanks for all the great posts and experiences.

I haven't been able to find an answer to my question though ... I have an RCA CANT2020 omni with built-in amplifier currently in my attic. It's been pretty solid until about 3 weeks ago, 50.1 and 4.1 completely fell off (I live in Windsor, Canada right accross from MI). I have a CM 7777 on the way which I will use with a borrowed 4 bay bow-tie, but can I hook up my omni to the 7777 VHF jack or will I fry the antenna or pre-amp?

But from what PCTools wrote, it looks like he may have too high of a voltage going to it.

Definitely. The CM-0747 is a simple linear supply, there's no way it should put out 22VDC even under no load. It's probably not actually doing so, more likely the big electrolytic failed and its putting out a lot of ripple. Not good for the pre-amp either way.

I have a CM 7777 on the way which I will use with a borrowed 4 bay bow-tie, but can I hook up my omni to the 7777 VHF jack or will I fry the antenna or pre-amp?
I wouldnt. Just use the CM7777 and the 4 bay bowtie combo by itself. I dont know about frying it, but you may decrease the performance of both antennas by combining them.

I wouldnt. Just use the CM7777 and the 4 bay bowtie combo by itself. I dont know about frying it, but you may decrease the performance of both antennas by combining them.

Thanks, I was thinking of that, but then what about VHF? The omni picks up UHF & VHF, so I can't combine the two ... right?

Sounds like this maybe the problem. The origianlly failing pre-amp was sent back to CM for examination. They confirmed that this pre-amp was in-fact good. I put up the replacement and it lasted about 30 days. Put up the Windgard in place of the 2nd failed pre-amp, and it worked fine.

So, if there was a problem in the coax I would doubt that buy changing the the pre-amp to the Winguard and installing it, and then she works would identify the coax is bad. Maybe, it has an intermittent issue. This is the RG6 stuff. From what I noticed, everytime the CM amp fails, I crawl on the tower, and replace it with the Winguard and everything works.

More to follow, as I continue to troubleshoot.

To make myself more clear.

Solid copper coax is recommended when passing voltage from point A to point B in the system. I have seen instances where the preamp seemed to have failed but in actuallity it did not. replacing the coax with solid copper fixed the problem. I recently encountered this problem even with a winegard preamp. replaced the coax and everything worked fine. The owner thought he purchased solid copper from radio shack, loews (not sure) and it was not.

The other thing to check for is a short...braid to center conductor, poorly seated fitting, corrosion, water ingress, etc.

You are getting bad information if you read or think that the coax does not make a difference. It does especially in this case..

I need to determine the rated output of this pre-amp power supply. My measurements were taken 3 foot of the transformer and yielded 22 Volts. I thought they were supposed to be around 18V. I swapped out 2 pre-amps and just used the same power supply. Perhaps, my problem is with the power supply.

Definitely. The CM-0747 is a simple linear supply, there's no way it should put out 22VDC even under no load. It's probably not actually doing so, more likely the big electrolytic failed and its putting out a lot of ripple. Not good for the pre-amp either way.

Thanks, I was thinking of that, but then what about VHF? The omni picks up UHF & VHF, so I can't combine the two ... right?

If the omni has seperate VHF and UHF outs just connect the VHF out to the VHF side of the CM7777.
If you just connect 2 UHF antennas you could have issues with multipath or ghosting.

Thanks for all the great posts and experiences.

I haven't been able to find an answer to my question though ... I have an RCA CANT2020 omni with built-in amplifier currently in my attic. It's been pretty solid until about 3 weeks ago, 50.1 and 4.1 completely fell off (I live in Windsor, Canada right accross from MI). I have a CM 7777 on the way which I will use with a borrowed 4 bay bow-tie, but can I hook up my omni to the 7777 VHF jack or will I fry the antenna or pre-amp?
We need your location, to whatever precision you chose (LAT/LONG and/or cross streets)
in order to determine distance to nearby towers and thereby advise whether
you are "too close" to use ANY amplified antenna or Preamp. For sure, do NOT
use an amplified antenna and THEN pass the output through a CM-7777 Preamp....
It will surely overload with so many towers surrounding you....

It would also help if you could post ALL CHANNELS results for your location
from www.tvfool.com and indicate which stations you DO and DON'T receive
with each antenna (ignoring stations you don't care about).
And which of the VHF stations can be received with the 4-Bay (with and
without a Preamp)....

From this we could see if you might want to try a 4-Bay without it's reflector...or whatever....

Google didn't say very much re RCA CANT-2020, but did find non-amplified ANT-2020:
http://www.globalsources.com/gsol/I/DVB-T-antenna/p/sm/1004775164.htm

Can you describe your RCA antenna and whether it has VHF coverage?
It might be similar to one of the following:
http://staytuned2tv.com/
Note that when horizontal, they have omni coverage:
http://staytuned2tv.com/resources/brochure_english.pdf
Unfortunately, RCA doesn't say what pattern is when hung vertically....

===========================
If you are NOT "too close", and are happy with the 4-Bay directionality for UHF,
you could use a UVSJ Combiner to combine UHF 4-Bay & Preamp OUTPUT
with the (VHF only) output of the amplified OMNI:
http://www.solidsignal.com/prod_display.asp?PROD=UVSJ
http://www.hollandelectronics.com/catalog/upload_file/Filters-Diplexers.pdf
http://yhst-18278607509093.stores.yahoo.net/pico-0389.html
Both P-M and Holland UVSJ pass DC only on the VHF port and block it on UHF port.

Note: You have to be VERY careful wrt how the Preamp and the OMNI get
DC voltage via each Power Insertion Module.
Power for OMNI goes THROUGH UVSJ, whereas CM-7777 Power Insertion Module
is located BETWEEN Preamp and UVSJ (meaning you need an attic AC outlet).

I would advise trying the UVSJ, except initially WITHOUT the CM-7777 Preamp.

If you chose to go down this path, let me know and I could send a diagram.

I need to determine the rated output of this pre-amp power supply. My measurements were taken 3 foot of the transformer and yielded 22 Volts. I thought they were supposed to be around 18V. I swapped out 2 pre-amps and just used the same power supply. Perhaps, my problem is with the power supply.
By opening up the power supply, you can see if the big cap is bulging and or leaking. A lot of Taiwanese caps made in 2001-2002 had bad electrolyte and will fail early.

[QUOTE=holl_ands;14974612]We need your location, to whatever precision you chose (LAT/LONG and/or cross streets)
in order to determine distance to nearby towers and thereby advise whether
you are "too close" to use ANY amplified antenna or Preamp. QUOTE]

Thanks for the great answer ... here are my answers in sections. This attachment shows my lat and long (couldn't see how to paste the pic in the post).

Google didn't say very much re RCA CANT-2020, but did find non-amplified ANT-2020:
http://www.globalsources.com/gsol/I/DVB-T-antenna/p/sm/1004775164.htm

Can you describe your RCA antenna and whether it has VHF coverage?
It might be similar to one of the following:
http://staytuned2tv.com/
Note that when horizontal, they have omni coverage:
http://staytuned2tv.com/resources/brochure_english.pdf
Unfortunately, RCA doesn't say what pattern is when hung vertically....


Well, my antenna doesn't look much like any of those. These attachments are pictures of the manual which shows it's specs and what it looks like.

I have also attached a quick cryptic sketch of my set-up. I have my 4-way currently bypassed, and my length of coax is under 90ft.

It would also help if you could post ALL CHANNELS results for your location
from www.tvfool.com and indicate which stations you DO and DON'T receive
with each antenna (ignoring stations you don't care about).
And which of the VHF stations can be received with the 4-Bay (with and
without a Preamp)....

From this we could see if you might want to try a 4-Bay without it's reflector...or whatever....

Note: You have to be VERY careful wrt how the Preamp and the OMNI get
DC voltage via each Power Insertion Module.
Power for OMNI goes THROUGH UVSJ, whereas CM-7777 Power Insertion Module
is located BETWEEN Preamp and UVSJ (meaning you need an attic AC outlet).

I would advise trying the UVSJ, except initially WITHOUT the CM-7777 Preamp.

If you chose to go down this path, let me know and I could send a diagram.


Okay, attached here is one file showing stations in my area (digital only) and the other shows digital and analog.

A diagram is always helpful in my books.

I hope everything I've supplied you is what you required. Thanks again.

A few clarifications before I look at the data....

It appears you used an East Detroit zipcode (48214) in above posted tvfool results.
Your actual location will have quite different results...

On the "Windsor, Canada" map, the LAT/LONG listed in the next line is actually in
Detroit at the location of the "pin" symbol.
Perhaps the mapping program doesn't work correctly for Canada....
no problem, we can do much better....

Using GoogleEarth to locate & convert units, the location you marked on the map is about
42-14-53N by 82-58-09W, which is 42.2481 by -82.9692 (within a few 100 meters).

Here are TVFool results for your location:

And here are Post-Feb2009 TVFool results:

A few clarifications before I look at the data....

It appears you used an East Detroit zipcode (48214) in above posted tvfool results.
Your actual location will have quite different results...

On the "Windsor, Canada" map, the LAT/LONG listed in the next line is actually in
Detroit at the location of the "pin" symbol.
Perhaps the mapping program doesn't work correctly for Canada....
no problem, we can do much better....

Using GoogleEarth to locate & convert units, the location you marked on the map is about
42-14-53N by 82-58-09W, which is 42.2481 by -82.9692 (within a few 100 meters).

Here are TVFool results for your location:


Yes, you are correct, it wouldn't give the actual Lat/Long for "Windsor, Canada", so I put the pic showing my actual location. Thanks for determining the actual location and for re-doing the TVfools results, it is VERY much appreciated! I look forward to your annalysis of the data.

Mariouchie:
You have very high signal levels, so amplified antennas & Preamps
can be a problem. So start without a Preamp on the 4-Bay.

Loss due to being in an attic can reduce the signal levels,
perhaps allowing the use of a low-gain, high overload
Preamp (e.g. W-G HDP-269). Overload blocks reception of
some of the weaker channels.

The stations you lost (4.1 & 50.1) are both quite strong,
coming from different tower locations. Perhaps they are
upgrading their equipment for Post-Feb2009 operations
before the winter weather gets really bad????

=====================================
You have strong UHF stations coming from several directions:
SOUTH: 172-deg (CBET, CICO, CBEFT)
NW: 317-323-deg (Windsor & Detroit clusters)
NORTH: 11-deg (WADL) and also 18-deg (W48AV, although weaker)

The more difficult to receive stations are as follows:
ESE: 105-118 (Whealey, Canada)
SW: 206-211-deg (Tuledo, Ohio)

The strong UHF stations will probably come in irrespective of which
way the 4-Bay is pointed. Unfortunately, the 100-deg spread
between Whealey and Tuledo greatly exceeds the beamwidth of a
4-Bay so if you pointed toward mid-point, both would have low gain:
http://www.hdtvprimer.com/ANTENNAS/cm4221.html

Perhaps you don't NEED to receive duplicate networks from Tuledo....

I would point the 4-Bay toward Whealey for max gain toward weakest
stations....tweak it back and forth until others come in okay.

If you have problems, remove the 4-Bay's reflector screen, which
adds a beam in the opposite direction.

Now let's discuss VHF channels:
Currently, CIII (Ch6, towards 118-deg) is only VHF channel of interest.
The 4-Bay has very low gain on Ch6 and may or may not get it (I'm betting against).

Post-Feb2009 results show WJBK (Fox) moving to Ch7 and
two Tuledo stations moving to Ch13 (ABC #2) and Ch11 (CBS #2).

The 4-Bay has low gain on Ch7, which may be just adequate to receive Ch7.
Since the 4-Bay wasn't specifically designed to receive VHF,
the beam directions could be pretty much in ANY direction
and wouldn't be particularly good for both WJBK and Tuledo.
But hopefully you don't NEED duplicate networks from Tuledo....
[Most antennas can't receive stations at right angles to each other.]

If the RCA amplified Omni is good enough for Ch6 now and
the other VHF stations in Feb2009, you can use UVSJ combiner.

If you are looking to upgrade VHF performance, CM-4228 8-Bay
antenna has moderate Ch7-13 gain and 5 dB more than the Omni on Ch6....
but it has a very narrow UHF beamwidth, meaning rotator use only.

If Ch6 is the ONLY VHF of interest, I would use simple rabbit ears
with UVSJ....or better still, a DIY Folded Dipole cut for Ch6:
http://www.n-lemma.com/calcs/dipole/fdipole.htm
http://www.wfu.edu/~matthews/misc/dipole.html
PS: Folded Dipole FM antennas sold by R-S, et. al. are "close" to Ch6:
http://www.radioshack.com/product/index.jsp?productId=2062691
[BTW: That's only a photo of the center, joining section.]

=====================================
FYI: Here is DIY Antenna thread. They show oversized 4-Bay Bowties
and Gray-Hoverman antennas optimized for Ch51 and below:
http://www.avsforum.com/avs-vb/showthread.php?t=798265

Hello,


I want to stack two Delhi 10y13s horizontally to kill co-channel interference on VHF ch 13. Delhi Website (http://www.wade-antenna.com/Wade/Yagi.htm)

My question is :

What it is the easy way to stack them?

They have to be 52.33 inches apart.

They will be mounted on my 40' tower but not on top (I have other antennas there).

They are going connected to the VHF input of my CM 7777. I have my CM 4228 connected to the UHF input.

What is the best method of combining them?

Thanks for your time,

Intravino

If the RCA amplified Omni is good enough for Ch6 now and
the other VHF stations in Feb2009, you can use UVSJ combiner.

If you are looking to upgrade VHF performance, CM-4228 8-Bay
antenna has moderate Ch7-13 gain and 5 dB more than the Omni on Ch6....
but it has a very narrow UHF beamwidth, meaning rotator use only.


Holl_ands,

Again, thanks for the great info.

No, I currently don't/can't get Ch6 with the Omni. I would like to upgrade my VHF, but with some of my major watching stations returning to VHF in 09, the directional 4228 may not be a good option (and I don't have power in the attic for a rotator). Looks like I will just try the 4-bay (with and with out CM7777) pointing ESE with the Omni through a Pico UVSJ or CM0549 (post pre-amps) and see what happens.

What "issues" do you thing adding the CM7777 would possibly create?

What "issues" do you thing adding the CM7777 would possibly create? The 7777 will not work in your situation. You signal levels are way too strong for a high gain pre-amp. You will lose all of your weak channels, and maybe even some of the stronger ones. If you find you do need a pre-amp for distribution needs, a low gain pre-amp like the HDP-269 like holl_ands recommended would be a good fit for you.

"Don't use a sledgehammer to put in a thumbtack";)

Totally agree....strong signals cause intermodulation distortion, which result in unwanted
noise on certain affected channels. With many strong signals, nearly ALL channels are affected.

Low gain HDP-269 will accept much higher signal levels than any other Preamp...
and high gain CM-7777 is on the other end of that scale....

Attenuation of signals within your attic is only thing that MIGHT allow you to use HDP-269.
Of course, since it is nearly impossible to predict how much loss you have, you'll
just have to try it and see how it works....

BTW: The HDP-269 has more than adequate gain to drive downlead and a bunch of RF splitters.
If you add a SECOND distribution amp, it can overload the input of your DTV. So don't...

Since the Omni doesn't pick up Ch6 now, there is no point in connecting it via UVSJ.
IF you indeed WANT to receive Ch6, try one of the options I listed above.

Hi.... I am totally overwhelmed here. There is too much info for me to sort through. Can someone please simplify things a little for me?

I live in an aparment building (amongst many in my neighborhood... Forest Hills (Queens), NY... Zip Code 11375). I can NOT have an Outdoor Antanna (it is NOT PERMITTED in my building). I do NOT subscribe to Cable or Sattelite or Direct TV, etc... I just receive whatever is broadcast free over the airwaves (regular Network TV stations). Is there some Indoor Antanna (that you know of) that I can purchase to help prevent the breakup of my reception when Digital takes over for Analog? Please specify brands and model numbers. Please e-mail me as well at CUEBALL070358 at AOL dot com.

Folks,
I just installed an Insignia NS-DXA1-APT converter box and I need your opinions. I have a large U/V Terk 55 on a Channel Master 9521 rotor. I live half way between Dayton,Oh(NE) and Cincy,Oh(So) and always have had to turn the antenna to receive all stations. My question, I am receiving all but three Dayton stations with the antenna pointed south. This includes 3 NE, 1 NW, 1 West, and all Cincy stations. The picture is great(signal strength down off direction), no ghosting or pixelation, how can this be?, and will this change in the winter?
Steve

Low gain HDP-269 will accept much higher signal levels than any other Preamp...
and high gain CM-7777 is on the other end of that scale
This comment leads me to question my situation.
47 miles from towers Winegard PR 8800 for UHF and 5 element Ch 3 only for my PBS station (Roanoke VA) - joined by a CM 7777 to one TV - Still have occasional CH 3 problems. Question ? is CM7777 too much? I would like to split signal to another TV. This might help because of the splitter? Or should I try the HDP 269 with lower gain.
Some possibly related information. There is another combo Radio Shack large antenna in the attic that I hooked up to feed three TV's with a RS 10db amp before the splitter and all worked well - as good or better than the two antennas on the roof with the CM777.
I am kind of lost between Pre-amp (strong or weak), splitter with strong pre amp, distribution amp with no pre amp etc?
I hope to go OTA only and want to use the cable company wireing that has their input going to a four way splitter and somehow use my attic and roof combo to feed the 4 TV's (2 to one -2 to the other)?
Thanks, Bernieoc

I need to determine the rated output of this pre-amp power supply. My measurements were taken 3 foot of the transformer and yielded 22 Volts. I thought they were supposed to be around 18V. I swapped out 2 pre-amps and just used the same power supply. Perhaps, my problem is with the power supply.

The power supply may be linear or switched, but unless it is regulated, then with a light or no load, you will likely read higher than the rated voltage. With the specified load you will be close to the rated voltage. For instance, just some quick and dirty data on some of the supplies that I put out with my products. These are tiny switchers, but I have some linears that are in the same arena. The output might also be a function of the input, but this isn't too common for switchers.

Rated, Measured
5V @ 150mA, 7.2V @ 20mA
9V @ 150mA, 13V @ 20mA

So I would not be surprised to see 22V on an 18V supply.

DTV PREAMP SIGNAL OVERLOAD CALCULATOR, RevK is attached, explaining how
to estimate received signal level and compare it to Preamp manufacturer specs.

Some manufacturers stipulate overload tolerance via input signal levels whereas
others use output signal levels.

Digital power is always measured with an average reading meter, whereas
NTSC/Analog power (assumed in manfacturer specs) is always measured
with a peak reading meter. And it's the PEAKS that cause the most damage....
Hence DTV average signal levels must be increased 7 dB to find peak signal levels.

Additional complication is taking the Cross Modulation Distortion (IMD) noise level
for the specified number of strong channels and then "derating" (lowering)
the maximum input signal levels when there are additional strong carriers....
And the reverse process when the manufacturer only specifies IMD levels
for a large number of (equally) strong channels.

You can use the line-of-sight calculator in the spread sheet, inputting antenna
gain and various loss corrections....or use www.tvfool.com Signal Pwr (dBm)
results, which need to be corrected by adding the gain of the antenna (in the
DIRECTION of the tower) and then
take away an estimate for various other factors, such as trees/attic/indoor loss
and balun/cable loss between antenna and Preamp.

Compare your calculated Preamp input signal level(s) (Sip) for the strongest
channels to the Max Sip (two channel case) found for each of fol. Preamps:

W-G HDP-269: -14.6 dB (76.2 dB dynamic range)
W-G AP-4700: -22.3 dB (68.5 dB dynamic range)
W-G AP-4800: -28.8 dB (62.0 dB dynamic range)
C-M Spartan 3: -34.5 dB (56.3 dB dynamic range) (e.g. 0068DSB)
C-M Titan 2: -35.8 dB (55.0 dB dynamic range) (e.g. CM7777)
B-T CMA-Uc: -31.2 dB (59.6 dB dynamic range)
B-T SCMA-Ub: -25.2 dB (65.6 dB dynamic range)

Of course this is all based on what little data we have from the manufacturers.
And don't even bother to ask about Radio-Shack, Antennas-Direct, et.al.
because they don't even bother to give specs....

=================================
Typical overload calculation involves trying to receive some distant weak channels
with a handful of nearby towers generating IMD noise on certain affected channels.
When there are more than a few strong signals, nearly every channel position is
affected, since third order IMD is spread across THREE adjacent channels
and lower level fifth order IMD is spread across FIVE adjacent channels, etc.

THIRD ORDER IMD CALCULATOR, RevA is also attached.
It calculates which channels are most affected, since third order is
stronger than fifth, seventh, etc. order IMD.
Examples are based on a few reported forum viewer situations.
You can also use INTMOD.EXE, a free download from NTIA:
http://ntiacsd.ntia.doc.gov/msam/

When there are more than two strong channels (remember to increase DTV by 7 dB),
tolerable input levels are less in order to maximize the dynamic range (SFDR).
See spread sheet for these derating details.

Additional information can be found by searching this forum for "SFDR"
(Spurious Free Dynamic Range), also see links in spread sheet.

PS: Please let me know if you have any "issues" with the spread sheets.....

I need to determine the rated output of this pre-amp power supply. My measurements were taken 3 foot of the transformer and yielded 22 Volts. I thought they were supposed to be around 18V. I swapped out 2 pre-amps and just used the same power supply. Perhaps, my problem is with the power supply.

I measured my CM0747 power supply at the antenna and it was 16.7 VDC no load. At the power supply end, it was 18 VDC no load.
So with about a 45 ft coax run, the voltage loss was about 1.3 VDC.

This comment leads me to question my situation.
47 miles from towers Winegard PR 8800 for UHF and 5 element Ch 3 only for my PBS station (Roanoke VA) - joined by a CM 7777 to one TV - Still have occasional CH 3 problems. Question ? is CM7777 too much? I would like to split signal to another TV. This might help because of the splitter? Or should I try the HDP 269 with lower gain.
Some possibly related information. There is another combo Radio Shack large antenna in the attic that I hooked up to feed three TV's with a RS 10db amp before the splitter and all worked well - as good or better than the two antennas on the roof with the CM777.
I am kind of lost between Pre-amp (strong or weak), splitter with strong pre amp, distribution amp with no pre amp etc?
I hope to go OTA only and want to use the cable company wireing that has their input going to a four way splitter and somehow use my attic and roof combo to feed the 4 TV's (2 to one -2 to the other)?
Thanks, Bernieoc
There aren't any TV or FM towers "nearby" Altavista, VA to cause a problem.
You can compare the Max Sip given above for various Preamps to your
"All Channels" www.tvfool.com Signal Receive (dBm) results (after correcting
for antenna gain and balun/coax loss).

Best performance is to use a MAST-MOUNTED Preamp...or if you don't want
to drop the antenna...as close as possible...
CM-7777 has enough gain to drive a long downlead AND a bunch of splitters....
Cascading TWO Preamp/Amps can overload TV...you can check via above spread sheet.

Folks,
I just installed an Insignia NS-DXA1-APT converter box and I need your opinions. I have a large U/V Terk 55 on a Channel Master 9521 rotor. I live half way between Dayton,Oh(NE) and Cincy,Oh(So) and always have had to turn the antenna to receive all stations. My question, I am receiving all but three Dayton stations with the antenna pointed south. This includes 3 NE, 1 NW, 1 West, and all Cincy stations. The picture is great(signal strength down off direction), no ghosting or pixelation, how can this be?, and will this change in the winter?
Steve

The Terk 55 appears to be bidirectional. Lots of people in Southwest Ohio (I live in Cincinnati) can easily pick up most of the stations in both cities by pointing the front of the antenna towards the other city and allowing the rear to pick up the stronger signals from the local city. I suspect this is what's going on in your situation.

I'm guessing the three stations you can't pick up from Dayton are WBDT, WKEF, and WGRT. The transmitter patterns for their digital stations currently point more power away from Cincinnati. (Some of this will change after analog shutoff though.)

Will your reception change once winter hits and the rest of the leaves fall off the trees? Perhaps. It may get better. It may get worse (due to the possible introduction of more multipath).

For more help, you can check out the Cincinnati HDTV thread (http://www.avsforum.com/avs-vb/showthread.php?t=306883).

I measured my CM0747 power supply at the antenna and it was 16.7 VDC no load.
At the power supply end, it was 18 VDC no load.
So with about a 45 ft coax run, the voltage loss was about 1.3 VDC.
Are you sure the "at antenna" measurement was with NO load???
Should be same as at power module unless you have a very low impedance
Volt-Ohm-Meter....or a very leaky coax...

Only measurement that makes sense is at antenna WITH LOAD.
If you don't have a zero-loss "T" connector to insert for measurement,
measure at antenna end with a resistor dummy load (Rd = Vrated/Irated),
where Vrated and Irated are the Preamp's rated operating voltage and current.

Question ? is CM7777 too much?Bernieoc,

There is a potent FM station on 88.3 that is a potential problem for you.(50,000 watts; just 5 miles NW of Altavista) The internal FM trap of the 7777 is ineffective on that frequency. Have you tried the channel 3 antenna with no amplification? I would try installing a true "full band" FM trap in front of the VHF input of the 7777 if nothing else works for you. That is the only thing I can see anywhere close to you that would cause the 7777 to overload.

Are you sure the "at antenna" measurement was with NO load???
Should be same as at power module unless you have a very low impedance
Volt-Ohm-Meter....or a very leaky coax...

Only measurement that makes sense is at antenna WITH LOAD.
If you don't have a zero-loss "T" connector to insert for measurement,
measure at antenna end with a resistor dummy load (Rd = Vrated/Irated),
where Vrated and Irated are the Preamp's rated operating voltage and current.

Good point. I remembered I measured at the power module with my good DVM. On the roof, I naturally took my cheapie Craftsman DVM.

W-G AP-4800: -28.8 dB (62.0 dB dynamic range)

Of course this is all based on what little data we have from the manufacturers.


As has been reported previously, the Winegard AP-4800 has a gain of about 36 to 38dB in the low 500 MHz range but was close to 28dB both below and above that frequency range, which messes up any calculations made using signal input or output levels that are furnished rather than measured.


In a head-to-head comparison I did with two Winegard AP-4727 preamps (23dB intermediate gain version of the 4700/4800) and two Channel Master ODS0064, 23dB UHF gain preamps, the weakest digital channels were rendered unprocessible at output levels about 10dB lower coming out of the Winegard preamps than out of the Channel Master preamps.

The 4221 and 4221A are basically the same thing. They have been discontinued and superseded by the 4221HD. While CM has released few specifications on the 'HD beyond average gain, its design is not radically different, and so there doesn't appear to be much justification for spending the extra money while the tried-and-true, older 4221s are still available.


Does anyone have any additional info on the 4221HD? Does the 4221HD provide any significant improvements and is it worth waiting for over the 4221.
There is very little info out there on the 4421HD.

Does anyone have any additional info on the 4221HD? Does the 4221HD provide any significant improvements and is it worth waiting for over the 4221.
There is very little info out there on the 4421HD.

It's lighter and it's made in China. Personally I wouldn't wait. It's a good, proven, solid design. Further, you know some people are going to swear it's better than the new one whether it is or it isn't, so there will be a resale market if you really want the 4221HD later on.

Warren Electronics is a often cited supplier here. Has anyone actually bought from them? How are they as a retailer? I called them today and a very knowledgable salesman talked to me for quite a bit, then emailed me a quote.

I am looking at a new Rohn tower. It is expensive to buy and expensive to have shipped. Warren Electronics' price is very fair. Can I expect a fair dealing with them? Are they reputable?

Any opinions would be appreciated as I am leaning towards them over a local electronics place.

Thanks!

Bill

I'm trying to put together a digital OTA solution so I can scrap Comcast. I live about 30 miles from the towers (Seattle), in the middle of the freakin' forest, surrounded by acres of extremely tall (>100') firs, hemlocks, etc.

I made a couple of bowtie antennas and bought a DTT901. I get good reception but the signal "strength" bounces all over the place from Good to Bad on several channels (esp. 13.1), and I get frequent dropouts. I'm guessing it's multipath. An amp made no difference according to the built-in signal meter.

I'd like to have the antenna inside, or in the garage, but could go outside if I had to, but using existing cabling the run would be about 50'. I tried taking a portable TV outside and trying it; better, but still problematic. AntennaWeb suggests a "medium directional antenna with pre-amp." I was considering the 4228HD but wonder if it'll really help.

Thanks all!

Is there a solution to this problem, or am I basically SOL because of the trees?

Is there a solution to this problem, or am I basically SOL because of the trees?
I dont think multipath is your main problem, firs and hemlocks because of their high water content, are notorious signal blockers. Can you find or clear a path to the station that is clear for a few hundred yards ?

Depending on your situation, you may be able to take advantage of the tall trees by mounting the antenna on top of one of them.

Depending on your situation, you may be able to take advantage of the tall trees by mounting the antenna on top of one of them.

Make sure you install proper grounding for the tree.

Make sure you install proper grounding for the tree.

Heh, the tree is properly grounded, and is more likely to get hit by lightning. (I speak from personal experience) But the coax needs to be properly grounded with a grounding block, as in any outdoor situation.

Okay, everyone who thinks I'm shimmying up a fifteen-story Douglas fir that sways 50' in the wind to install a 300' run of cable and my homemade bowtie--raise your hands!

Seriously, would even a 4228 suffer from my location?

I made a couple of bowtie antennas and bought a DTT901. I get good reception but the signal "strength" bounces all over the place from Good to Bad on several channels (esp. 13.1), and I get frequent dropouts. I'm guessing it's multipath. An amp made no difference according to the built-in signal meter.

I think you will want to try a Yagi class antenna, such as the 91XG. However, an upper VHF antenna will need to be added next year when 9, 11 & 13 go back to VHF in Seattle.

A CM4228 might solve your problem and has some upper VHF gain. However, I would be inclined to go with a 91XG and a YA1713 in the woods (with a rotor, if you want the non co-located stations).

Okay, everyone who thinks I'm shimmying up a fifteen-story Douglas fir that sways 50' in the wind to install a 300' run of cable and my homemade bowtie--raise your hands!

Seriously, would even a 4228 suffer from my location?

The tree would sway too much for a 4228. Try a 4221 instead.

How far apart are the branches on a Douglas Fir?

However, an upper VHF antenna will need to be added next year when 9, 11 & 13 go back to VHF in Seattle.

A CM4228 might solve your problem and has some upper VHF gain.

You could also try building mclapps 4 bay bowtie with the large reflector for VHF-Hi channels as well as UHF channels. His designs for it are in the "How to build a UHF antenna" thread of this forum.

Ive found that generally bowties and Gray-Hoverman designs do better at catching signals thru trees than the corner reflector yagi style antennas.

How far apart are the branches on a Douglas Fir?

At the top, they are very close together. He'll have to take a saw with him to clear an area to mount the antenna.

I was able to test a CM-4221 this weekend using my make shift antenna range. Testing was done with a B&k 2630 spectrum analyzer using the tracking generator as the transmitter into a dipole antennas cut for UHF & VHF-hi.
The transmit and receive antennas were about 20ft off of the ground and seperated by enough to be considered far field measurements. The readings were compared to a series of folded dipoles cut for both VHF-HI and UHF.

On UHF it showed about 6.5 dbd at ch14 and climbed to 11.5 dbd on ch36 where it stayed pretty steady (+-1db) through ch69.

On VHF-hi the CM4221 has a negative gain of around -15dbd on ch7 rising to -1dbd on ch13. It has better gain through the screen on the lower vhf-hi channels, about 2 - 5db better until ch12 where it's about even.

By adding a 36" wide piece of screen or a series of 36" threaded rods (horizontal) to the back of the original reflector, the CM4221 actually has positive forward gain in the range of 2-4dbd from ch10-13 and peaked at around 5dbd above ch 13. It still dropped off pretty fast below ch9 to -10dbd by ch7 but that is still a 3 - 7db improvement over the factory screen depending on the channel.

I know most of this is old news but other than some computer modeling results I've never seen any actual test results of it's UHF and VHF-hi performance.

It was interesting to see how a few pieces of 36" threaded rod attached to the back of the reflector screen made so much difference. I had modeled it and the models showed some gain but you never know till you try it.

mclapp,

Thank you performing the testing and sharing this information.

It's good to hear the results come in line with the modeling.

Bill,

Warren Electric are a decent supplier. Just out of curosity what are they quoting you for the Rohn 20?

I bought my tower 6 months ago and paid around $70 for the mid's and $80 for the top.

I know this stuff is pricey, so shop around.


Warren Electronics is a often cited supplier here. Has anyone actually bought from them? How are they as a retailer? I called them today and a very knowledgable salesman talked to me for quite a bit, then emailed me a quote.

I am looking at a new Rohn tower. It is expensive to buy and expensive to have shipped. Warren Electronics' price is very fair. Can I expect a fair dealing with them? Are they reputable?

Any opinions would be appreciated as I am leaning towards them over a local electronics place.

Thanks!

Bill

paid around $70 for the mid's and $80 for the top.Delivered?

I priced tower sections at a local radio store a couple of years ago at about $125 per. Prices I've seen on the net look to be as much or more delivered.

-Neil

It was interesting to see how a few pieces of 36" threaded rod attached to the back of the reflector screen made so much difference.
It would be interesting if you could replace the threaded rod with plain rod and see if it makes a significant difference. Threaded rod is one of those things that are near impossible to model, heh.

I hate to be one of those people asking for spoon feeding, but I have read through the numerous faqs and spent hours on this thread. I'm a longtime lurker, but not a poster. I'm looking to get this setup going in the next few months, so I've attached the "post 2/17" results from my location.

I have many tall (greater than 40ft) trees in my backyard, but do have a fairly clear view of the southern sky. (Currently receiving di$hnetwork at 110/119w. with plans to cancel soon). No tall apartment buildings nearby, but within 2 miles there are extremely high hydro lines. My receiver intention is the Hisense db-2010 and I'm of course looking for antenna recommendations. Alot of people seem very happy with the CM4228 but I wanted to run it by the experts and get some mounting suggestions.

I am really only interested in receiving HD broadcasts on the major networks. Thanks guys!

It would be interesting if you could replace the threaded rod with plain rod and see if it makes a significant difference. Threaded rod is one of those things that are near impossible to model, heh.

The reason I used threaded rod was (1) I had a bunch and (2) I figured it would be worst case anybody would use for reflector elements. The difference in gain between the (8) 36" long 1/4-20 threaded rods and the 36"wide x 36"tall 1"x2" wire fence was almost nothing on VHF-hi. Both were attached to the back original screen with just some plastic spring clamps and 1 vise grip.

Yes it would be tough to model but I don't think the threads would come into play at TV frequencies.

Here's his results from digital home.

http://www.digitalhome.ca/forum/showthread.php?t=41072&page=33

The difference in gain between the (8) 36" long 1/4-20 threaded rods and the 36"wide x 36"tall 1"x2" wire fence was almost nothing on VHF-hi.

Thats good to know. I figured for VHF-Hi, it would only be a minor difference at best. Oddly, 1/4 inch threaded rod is much cheaper at Lowes and Home Depot than 1/4 inch solid rod, heh.

I have many tall (greater than 40ft) trees in my backyard, but do have a fairly clear view of the southern sky.
What kind of trees ? Do you have 148 degrees magnetic clear ? How about the situation at 328 degrees magnetic ?

I am really only interested in receiving HD broadcasts on the major networks. Thanks guys!


Your signals are quite strong, and if it wasnt for channel 8, you could do fine with a reflectorless Gray-Hoverman.

Bill,

Warren Electronics is a good supplier. I have made many purchases without any issues.

As far as Rohn 20 tower prices, get ready to unload your wallet with current steel prices.

The best deals I secured on my tower is as follows:
Top $89 X 1
Mid's $73 X 4

I paid $620 for a 50' install, concrete, and a stacked array mounted on top. (Not including antennas or pre-amp)

Warren Electronics is a often cited supplier here. Has anyone actually bought from them? How are they as a retailer? I called them today and a very knowledgable salesman talked to me for quite a bit, then emailed me a quote.

I am looking at a new Rohn tower. It is expensive to buy and expensive to have shipped. Warren Electronics' price is very fair. Can I expect a fair dealing with them? Are they reputable?

Any opinions would be appreciated as I am leaning towards them over a local electronics place.

Thanks!

Bill

I was able to test a CM-4221 this weekend using my make shift antenna range. Testing was done with a B&k 2630 spectrum analyzer using the tracking generator as the transmitter into a dipole antennas cut for UHF & VHF-hi.
The transmit and receive antennas were about 20ft off of the ground and seperated by enough to be considered far field measurements. The readings were compared to a series of folded dipoles cut for both VHF-HI and UHF.

On UHF it showed about 6.5 dbd at ch14 and climbed to 11.5 dbd on ch36 where it stayed pretty steady (+-1db) through ch69.

On VHF-hi the CM4221 has a negative gain of around -15dbd on ch7 rising to -1dbd on ch13. It has better gain through the screen on the lower vhf-hi channels, about 2 - 5db better until ch12 where it's about even.

By adding a 36" wide piece of screen or a series of 36" threaded rods (horizontal) to the back of the original reflector, the CM4221 actually has positive forward gain in the range of 2-4dbd from ch10-13 and peaked at around 5dbd above ch 13. It still dropped off pretty fast below ch9 to -10dbd by ch7 but that is still a 3 - 7db improvement over the factory screen depending on the channel.

I know most of this is old news but other than some computer modeling results I've never seen any actual test results of it's UHF and VHF-hi performance.

It was interesting to see how a few pieces of 36" threaded rod attached to the back of the reflector screen made so much difference. I had modeled it and the models showed some gain but you never know till you try it.
Good work....but I have some hopefully CONSTRUCTIVE comments re Ground Bounce,
esp. if anyone else attempts to replicate results.....
I would also be interested in how you avoided or accounted for this effect...

The receive antenna receives not only direct LOS signal, but also a "Ground Bounce"
reflection with a somewhat longer path length.

The path difference causes constructive and destructive interference, depending
on whether ground bounce signal is in-phase with LOS signal (multiple of the wavelength)
or out-of-phase (odd multiple of half wavelength, e.g. L/2, 3L/2, 5L/2, etc).

At higher UHF frequencies, this path difference can even vary across the height
of a typical multi-bay antenna....at which point constructive gain overwhelms nulls.....

The destructive null is fairly sharp...and more likely at lower UHF frequencies.

For more consistent measurements, either the TX or RX antenna can be raised
and lowered until the receive signal level is at maximum constructive interference.
With a good ground reflection, free space gain of the antenna would be 3 dB LESS.

Some professional antenna ranges employ RF absorbent material and irregular
surfaces to scatter the ground bounce energy. However, this is very difficult
(and expensive) to do at VHF frequencies....testing across a canyon can help....

Horizontal polarization is more efficiently reflected than vertical polarization
(same principal as polarized sunglasses), hence outdoor antenna test ranges
typically mount antennas rotated 90-degrees with elements going up and down.

One way to completely avoid ground bounce problem is to use a very short pulsed
waveform so the measurement is complete before the reflection appears....

Additional info:
http://www.lehman-inc.com/pdf/mag.pdf
http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/11595/1/02-0109.pdf
http://www.exirbt.com/BroadcastingSupport/BroadcastingSupport/AntennaTestRange.aspx
Hey!!!! Who stole my Volvo Sportwagon????

=========================================
FYI: Detailed CM4221 (et. al.) NEC Sim results (in dBi = dBd + 2.15 dB) are found in ant.xls:
http://www.hdtvprimer.com/SIMS/
CM4221 net gain peak was 14.9 dBi (12.7 dBd) and Ch16 (lowest UHF) was 9.2 dBi (7 dBd).
So above test range results are remarkably close (but LOWER) than NEC Sim runs....

Alot of people seem very happy with the CM4228 but I wanted to run it by the experts and get some mounting suggestions.


Your signals are fairly strong for the most part, unless you are looking for out of market stations as well. The old CM4228 had a bit of a null for channel 8, but I don't know if the new version eliminates that problem.

WBRA isn't worth spending any money on (to add Low-VHF capabilities).

If it wasn't for WGHP on 8, I think the CM4221 would be more than enough for your locals. As the 4221 is very poor on 7 and barely passable on 9, it's probably too risky unless you wouldn't mind adding an upper VHF antenna for WGHP.

A real 7-51 combo, you may want to consider is the Winegard 769 series (if you don't mind a Yagi style):

http://www.solidsignal.com/prod_display.asp?prod=HD7694P

A CM2016 may be enough as well:

http://www.solidsignal.com/prod_display.asp?prod=CM2016

Hollands,

What are your thoughts about aiming your antenna array at a water tower? That is, I will have a NEW 200' water tower about 1800 feet away from my tower.

1) So you think I would have any luck catching the bouncing signal off the water tower and picking it up? I figure this could be a fantastic idea on how close I am to it, or it could just be a complete mess in blocking my view to Detroit.

2) I sent you a PM.

Thanks!

PC Tools,

Thanks.

WOW! That is cheap!

I was looking at $121 for 3 main sections and $150 for the 9' top section of Rohn 25. I would do the install myself.

Bill

Rohn 25
Mids - $95
Top - $150

PC Tools,

Thanks.

WOW! That is cheap!

I was looking at $121 for 3 main sections and $150 for the 9' top section of Rohn 25. I would do the install myself.

Bill

I have 4 TVs in an older house with no easy way to distribute the signal from a roof antenna I think I'm going to need now save fishing cables and even that would be difficult in at least one of the cases. I think I've seen in the past systems that could distribute an RF signal over the house wiring, and think there must be someone who has tackled the job of making an ultra high frequency system, but some pretty extensive searching has so far not yielded any results. To be clear, I am not interested in sending a signal from one box to all the TVs, but from the antenna to the TVs so that they can be tuned to different channels. Any help?

mar9tin,

Best thing would be to run antenna coax from the antenna to each TV either through the attic and drop down through walls, or through the crawl space and just up through the floor (or walls).

If neither of those will work, go around the outside of the house and run your cable through the wall where you need it. I've seen many cable and satellite installs done just that way. It's not pretty but it works and is easy.

-Neil

holl_ands,
I know exactly what you are talking about I had bad problems with this when I set up my original testing, mainly with the reference dipoles which radiate at higher angles.

How I minimized the ground bounce effect was to raise the antennas as high as I reasonably could (approx. 20ft above ground) and placed them as close to each other as I could. There is a formula for the minimum spacing that is allowed and still be considered far field, it has to do with frequency and the antenna capture area.

Using some sort of antenna like a stacked bowtie or corner reflector for the transmit antenna would probably help too but the dipole is nice because it allows me to change element lengths quickly for the different bands.

Using the tracking generator of the spectrum analyzer allows you to see the whole responce curve of the antenna (within the limits of the transmit antenna) that helps show any ground bounce problems. They show up as big shrp dips and peaks in the curve and that's what I was getting when I had the antennas too low and too far apart, especially the dipoles. It drove me nuts for a few days trying to figure out where they odd curve was coming from and why it was mainly the dipoles.

I did most of this testing to varify the modeling results of some of the antennas I was building. I wanted to see if I was heading down the right road and if the modeling gain results were anywhere near actual builds.

Those 4221 results are quite close to the modeled results I didn't really compare them until you mentioned it. I could be easily off +-1db for a number of factors compared to the computer models. (1) The display on the analyzer is in 2 db divisions so I'm estimating the reading between the divisions(reading between the lines) (2) I'm using a balun and a length of coax and there will be areas where the length of coax may just the right length to (fix) bad impedence matches and make it worse in others. (3) In the bowtie antennas and many others the mounting points can detune the antenna somewhat at certain frequencies, the computer models don't take that into account.
I'm sure that there are many more but those are the biggies.

Thats good to know. I figured for VHF-Hi, it would only be a minor difference at best. Oddly, 1/4 inch threaded rod is much cheaper at Lowes and Home Depot than 1/4 inch solid rod, heh.


What kind of trees ? Do you have 148 degrees magnetic clear ? How about the situation at 328 degrees magnetic ?



Your signals are quite strong, and if it wasnt for channel 8, you could do fine with a reflectorless Gray-Hoverman.

Your signals are fairly strong for the most part, unless you are looking for out of market stations as well. The old CM4228 had a bit of a null for channel 8, but I don't know if the new version eliminates that problem.

WBRA isn't worth spending any money on (to add Low-VHF capabilities).

If it wasn't for WGHP on 8, I think the CM4221 would be more than enough for your locals. As the 4221 is very poor on 7 and barely passable on 9, it's probably too risky unless you wouldn't mind adding an upper VHF antenna for WGHP.

A real 7-51 combo, you may want to consider is the Winegard 769 series (if you don't mind a Yagi style):

hxxp://www.solidsignal.com/prod_display.asp?prod=HD7694P

A CM2016 may be enough as well:

hxxp://www.solidsignal.com/prod_display.asp?prod=CM2016


Thanks for the replies guys. The trees in the backyard are higher than a 3 story building, and very thick (pines, mixed/forested).

However, out the front I have clear visibility. The front of the house faces south, leaving me a clear view ranging from 90-300 degrees.

Like my attachment, I am mainly interested in picking up digital (HD) feeds of:

antennaweb:
uhf WCWG-DT 20.1 CW LEXINGTON, NC 145° 15.3miles
uhf WXLV-DT 45.1 ABC WINSTON-SALEM, NC 145° 15.3miles
vhf WGHP-DT 8.1 FOX HIGH POINT, NC 156° 17.7miles
uhf WMYV-DT 48.1 MNT GREENSBORO, NC 145° 15.3miles
uhf WFMY-DT 2.1 CBS GREENSBORO, NC 148° 14.5miles

FOX 8 is the only VHF, but I definitely want this OR the next closest FOX which can be shown in the attachment. But is about 60-80miles away.

These below channels I would also want, but as noted above, I really don't have a clear view of, unless going through trees is an option? I can't mount any antenna with a clear view ABOVE the tree line.

uhf WXII-DT 12.1 NBC WINSTON-SALEM, NC 327° 31.3miles
uhf WGPX-DT 16.1 ION BURLINGTON, NC 60° 24.7miles


Appreciate the info and honesty,

Thanks guys!

I wanted to inquire your feedback on my location.

As you can see, I am out in the middle of sticks.

Any feedback would be great!

http://img514.imageshack.us/img514/2374/1112200851106pmhn9.jpg

I wanted to inquire your feedback on my location.



I count about 21 DTV stations from eight-nine different directions.

I hope that you have a rotor and a TV that can add channels one at a time.

Your second TV set probably wants it own antenna fixed at the main group of stations at 224 degrees.

Like my attachment, I am mainly interested in picking up digital (HD) feeds of:

antennaweb:
uhf WCWG-DT 20.1 CW LEXINGTON, NC 145° 15.3miles
uhf WXLV-DT 45.1 ABC WINSTON-SALEM, NC 145° 15.3miles
vhf WGHP-DT 8.1 FOX HIGH POINT, NC 156° 17.7miles
uhf WMYV-DT 48.1 MNT GREENSBORO, NC 145° 15.3miles
uhf WFMY-DT 2.1 CBS GREENSBORO, NC 148° 14.5miles

FOX 8 is the only VHF, but I definitely want this OR the next closest FOX which can be shown in the attachment. But is about 60-80miles away.


You should be very fine with mclapps wide reflector 9 1/2 X 8 bowtie for those stations.
These below channels I would also want, but as noted above, I really don't have a clear view of, unless going through trees is an option? I can't mount any antenna with a clear view ABOVE the tree line.

uhf WXII-DT 12.1 NBC WINSTON-SALEM, NC 327° 31.3miles
uhf WGPX-DT 16.1 ION BURLINGTON, NC 60° 24.7miles
Pines are tough, because of their high water content. But the signals are strong and you may be lucky. Try the SBGH for those stations.

You should be very fine with mclapps wide reflector 9 1/2 X 8 bowtie for those stations.

Pines are tough, because of their high water content. But the signals are strong and you may be lucky. Try the SBGH for those stations.

Thanks for the info.

I was planning on ordering something commercial. I'm not much of a DIY'er. Although all the plans I've seen for it have had so many changes and revisions, I wouldn't know what the best option to choose (updated link perhaps). Do you think I'd be alright with the attic mount then? and are you suggesting the ONLY way to pick up both the first group of channels, and then the tree obstructed ones in another direction would be to use 2 antennas? I couldn't pull it off with a multidirectional?

Appreciate all your info and knowledge. I've literally spent hours reading your posts across the various threads, and it's just all so overwelming.

PCTools check mine out. Mine is alot like yours. I have just started testing mine out and i will give some results i am getting. My stacked 91xg's are spaced 54 1/2" apart. I am using a 4-way stripline combiner because i wanted to stack four and will in the spring. So i have two inputs capped or dummy loaded but guessing i have more loss than a 2-way. I think on uhf, trees, hills and so much plays apart on just how good we can do. I think anything out to 70 or 75 miles out we can maybe lock in pretty good. That is if trees and things don't kill the signal to bad.

I have noticed weather plays apart with mine, if a rain moves in. I have many trees around me and i need to get up 20 more feet or even 30 ft and i feel it would help me. I am up 55 ft now. Mine are so so directional it isn't funny. I can be off a few degrees and cut things out. I was looking at some stations 95 to maybe 125 miles late last night, as they would fade in and out with 2 bars(Samsung 260f). I kept messing with rotor and got them at 4 bars and after awhile i finally got them at 7 or 8 bars and even at times might go to full 10 but mainly stay at 8 before it would fade down some. I mean i had to move a lil bit either way but even then at times i would get fade to fade out and back in but not bad. The farther out it seems, the fade seems to be worse. I feel us having maybe 4 antennas might help on this, to maybe hold better.

At 75 miles out, they hardly ever fade out if i am on them. The problem, i don't have alot at 75 miles. WPSD i can always lock in very good and it has a few sub chs. It is 73 miles away. I have not played with the antenna alot pointing towards Memphis but the couple times i tried, i did not get anything except closer stations. WKMU at 30 miles from me has 4 pbs chs and i like them and they always lock at 10 bars. I get them and even WPSD and maybe another or two on the sides of the antennas as well. I do not have as many trees going north and i lock in more north.

Here are some stations i have been picking up and even Nashville during the day or if weather gets bad, Nashville gets bad. If not, i can do good getting anywhere from 6 bars and even locked in WKRN from 7 to 10 bars from nothing in bad rainy weather. Maybe leaves from trees mess with signals. The ones i have listed below is ones i have written down and will test more. I wish i had a 1080 tuner that was very sensitive. I like the Samsung alot and i only want a 1080 tuner but i wish they made one even more sensitive. I wish i was up 30 more ft. I want to stack 4 instead of 2. We need a high gain antenna that cuts off at ch 50. 14-50 and maybe around feb, maybe the 91xg's will be tuned with back driven element from these chs instead of up to 69.

WTCT Marion, IL 96 miles. Fair but drops in and out.
WSIU Carbondale, IL 135 miles. Not to good, drops out to much.
WKRN Nashville, TN 83 miles. This one does good and can lock in good. 6 to 10 bars.
WTVF Nashville, TN 84 miles. This is ok also but not as strong as WKRN.
WZTV Nashville, TN 83 miles. Does good.
WHTN Nashville, TN 105 miles. Has drop outs.
WPSD Paducah, KY 73 miles. This one is always strong.
WKMU Murray, KY 30 miles. Always strong.
WBBJ Jackson, TN. 51 miles. Most of time strong.
WJKT Jackson, TN. 57 miles. Mostly strong.
WSIL Southern IL. 96 miles. Does pretty good.
KFVS Cape Girardeu, MO. 103 miles. With fine tunning, this does good.
WDKA Not sure where it's at. 84 miles. Does ok.
KBSI I think in IL, maybe MO. 104 miles. Fair.

The slightest turn or move on antenna, if i turn, can go from signal to none. Yours looks alot like mine, we are bad deep fringe. All the chs above seems to have sub chs and some of the subs i like. I did not want to mess with guy wires and i do not have a self standing tower, so if i go up higher, i will need to mess with guy wires. I am using Channel Master 7777 and if i take it out of line, signal drops to nothing or very little. I am using rg11 from preamp down, now i do not have anything on vhf side of preamp but hope to have the vip-306 up in the next week or two. If 4 stacked helps on less fade, it would be well worth it. Thanks all in here that has give me tips on installing the stacked 91xg's. Your pics PCtools, also helped. I will take more pics as these pics do not show rotor and doesn't show antennas pushed up 5 ft out of tower. I am going to move scanner antenna down and ground everything. Nothing is grounded yet but i have ground ready.

In my last post, i meant self supporting tower. Then i would not have to have guy wires up higher. I wanted to say, it is raining hard here now and anything 75 miles or more out, on a couple scans i just made doesn't seem i am picking up. WPSD at 73 miles is great and i didn't go all differ ways but when it rains it seems to really knock far signals back or off for me. Maybe it is the leaves.

Has anyone in here, tested a channel or channels with no ground and then test when you get your ground wire on. I wonder when grounded, if it could help in signal, if it could help any with fade or if it does not do nothing on signals but ground you.

Do you think I'd be alright with the attic mount then?

Go ahead and try the attic mount first, since thats the easiest option. Then if performance isnt satisfactory, go for the outdoor mount.

and are you suggesting the ONLY way to pick up both the first group of channels, and then the tree obstructed ones in another direction would be to use 2 antennas? I couldn't pull it off with a multidirectional?

There are no multidirectional TV antennas with great gain, at least not yet. Ganging 2 antennas that face in different directions DECREASES gain on each, so thats why I suggest two antennas, two down leads, into an A-B switch. Or you could go the antenna rotor route, which is painfully slow. (30 second wait for a 180 degree turn)

There are no multidirectional TV antennas with great gain, at least not yet. Ganging 2 antennas that face in different directions DECREASES gain on each, so thats why I suggest two antennas, two down leads, into an A-B switch. Or you could go the antenna rotor route, which is painfully slow. (30 second wait for a 180 degree turn)
Theoretically two identical highly directional antennas pointed in exact opposite directions should not effect each other, but unfortunately in the real world every antenna is a part of its environment so there really aren't any identical antennas. Perhaps in the future with the help of electronics there will be a high gain bi-directional TV antenna.

Which antenna would be better the 91XG or the CM 4228?

The stations are around 68 miles away. I have a tree line about 120 yards from where the antenna would be mounted about 30ft. from the ground on the chiminey. I'm guessing the trees are about 15 or 20 foot taller than antenna. I already have a Channel Master 7777 pre amp.

Theoretically two identical highly directional antennas pointed in exact opposite directions should not effect each other.

The antennas may not interact, but adding them together changes everything.

I would choose the 91XG because in the case of those trees you can tilt up the 91XG about 15 degrees or so to somewhat compensate; I have that same tree problem and the 91 XG does me pretty well. I don't know your entire situation but I had to add a rotor because of trees. There is actually a couple of trees in the yard next door and depending on the station I'm aiming for, I can rotate the antenna to one side of the tree to the other to better pick up certain channels here. But I would definitely get the 91-XG I ordered mine from Solid Signal. Also have the CM7777 amp but am thinking about removing it because of overload.

Thanks bozey45. One reason I was looking at the 91xg was how lite it is compared to the 4228 for rotor use.

On the 91xg where does the mast mount? Does it slide into the bottom or does it clamp on to the side some how?

Thanks bozey45. One reason I was looking at the 91xg was how lite it is compared to the 4228 for rotor use.

On the 91xg where does the mast mount? Does it slide into the bottom or does it clamp on to the side some how?

http://www.solidsignal.com/manuals/91XG_Instructions.pdf

http://www.solidsignal.com/prod_display.asp?PROD=TD-91XG

I've done a number of experiments with this antenna, and IMHO, it's quite good. Good gain and narrow beamwidth, which helps to reduce multi-path issues.

Steve

Thanks bozey45. One reason I was looking at the 91xg was how lite it is compared to the 4228 for rotor use.

On the 91xg where does the mast mount? Does it slide into the bottom or does it clamp on to the side some how?

Here is a picture of mine, which was just put up, getting a good signal on 2 stations 78.2 miles away, and I am 200+ft in a valley!

http://i151.photobucket.com/albums/s129/gjvrieze/TV/Picture003.jpg

Alright sounds like it might work better than the 4228. Thanks

Not sure which antenna thread to use. If this is the wrong thread let me know.

Question, has anyone tried any of the new commercial Winegard High Band VHF/UHF combo antennas? They are all pretty new as far as I know, but hey I could be wrong.

If you need a list of the ones I am talking about let me know or this is the correct thread.

Hey guys,

I did my homework and finally settled on a BD4 to install at my house. For those of you who own one of these, it came with a little rubber thingie that I assume is supposed to seal the connection. How in the heck does it do that? Also, does any one have any pointers on how to waterproof my connections?

TIA,
KC

Thanks for the updated plot. It looks like you will need to go with a rooftop, outdoor antenna. Unless there is something on the channel 2 translator that you want to watch and since KDLO appears to be out of the range of reliability, a 7-51/69 antenna, with a rotor and possibly a pre-amp will be needed.

Channel Master is coming out with some new models soon, but for right now, the following Winegard antenna would be something to consider.


If you are looking for an attic mount, the CM4228 may get it done for UHF, but attic mounts are difficult for a VHF antenna that may need to be turned.
Thanks for the reply. I have one more question.

I don't know that I will be able to get a rotor up there. If I aim it towards KVVR CH 19 at 330 degrees, will I be able to pick up any of the channels behind to the SW?

Thanks.

Totally agree....strong signals cause intermodulation distortion, which result in unwanted
noise on certain affected channels. With many strong signals, nearly ALL channels are affected.

Low gain HDP-269 will accept much higher signal levels than any other Preamp...
and high gain CM-7777 is on the other end of that scale....

Attenuation of signals within your attic is only thing that MIGHT allow you to use HDP-269.
Of course, since it is nearly impossible to predict how much loss you have, you'll
just have to try it and see how it works....

BTW: The HDP-269 has more than adequate gain to drive downlead and a bunch of RF splitters.
If you add a SECOND distribution amp, it can overload the input of your DTV. So don't...

Since the Omni doesn't pick up Ch6 now, there is no point in connecting it via UVSJ.
IF you indeed WANT to receive Ch6, try one of the options I listed above.

Holl_ands,

I just wanted to give you an update to my situation. Unfortunately, I was unable to post earlier due to my DTV dying on me in the midst of everything.

I know I was told to not use the CM7777, but 4.1 and 50.1 were at 52% and 63% respectively on a good day, and would fall off all the time (and at the worst possible times of course). Since I had the CM7777 in hand (and the time), I determined it was better to try it than to not and have to wait a week for a hdp269. My guess is there are more losses in my attic than expected. Once hooked up, 4.1 and 50.1's signals increased by 20% and none of the remaining stations fell off. It has been running for a several days now, and still no fall off's. I know this is NOT how it's supposed to be set-up and that it really shouldn't be working ... at all, but it's working. So, if it's working, I don't think I'm going to try and fix it.

The fact that I have a situation working for me, that defies all logic and reason, is ridiculously fitting for me.

Thanks again for all your help and great posts!

Was wondering if I posted what I have done so far if I could have someone with more experience critique and suggest any improvements.

I live in Camp Hill, PA and wanted to have my computer hooked up to my LCDTV act as a DVR. Wife factor means I can't have a rotor attached, thus I need to get ABC, CBS, FOX, PBS & NBC all consistently on a omni-directional antenna.

I purchased a DB2 Generic (American Eagle I think) and next to my chinmey (two story home). I have to run the cable down the side of the house, into the basement and then back up into our second story bedroom (my guess is the total coax length is 100' or so. Based on research that indicated longer than 50' requires a pre-amp, I purchased a Channel Master 7777 and isntalled.

Installed all the equipment and get good connection on all channels, though signal strength tends to bounce around somewhat (mostly on CBS). I believed that if I moved the power source from the pre-amp from my TV to the basement (now 50-60' between pre-amp and pwer supply), and then fed the output from the pre-amp into a powered 4 wasy splitter (for the remaining 40-50'), it would boost the signal strength to the TV and solve the fluxuating CBS signal. Truth be told, I lost CBS completely, though all other stations signals were better. I posted over at another forum and someone thought that it might be the signal is too strong, which may be the case. Based on TVFool's analysis of my location, I should be able to get away with an indoor antenna for most stations except FOX, but I found I had to do a lot of pointing to get each channel when the antenna was inside the house.

I do forsee CBS getting better as they transition from VHF to UHF on Feb. 17, 2009, however my NBC station is converting from UHF to VHF and is farther away, so I am worried about how that will play out.

Anyway, any suggestions on how to improve. Also, I have not installed the grounding clamp yet, I don't have anything to ground to other than the cold water pipes. Should I just ground to that or should I go buy a grounding rod and drive it into the ground and ground to that. Like I said, newbie here, so don't be affraid to point out my mistakes.

Was wondering if I posted what I have done so far if I could have someone with more experience critique and suggest any improvements.

I live in Camp Hill, PA and wanted to have my computer hooked up to my LCDTV act as a DVR. Wife factor means I can't have a rotor attached, thus I need to get ABC, CBS, FOX, PBS & NBC all consistently on a omni-directional antenna.

I purchased a DB2 Generic (American Eagle I think) and next to my chinmey (two story home). I have to run the cable down the side of the house, into the basement and then back up into our second story bedroom (my guess is the total coax length is 100' or so. Based on research that indicated longer than 50' requires a pre-amp, I purchased a Channel Master 7777 and isntalled.

Installed all the equipment and get good connection on all channels, though signal strength tends to bounce around somewhat (mostly on CBS). I believed that if I moved the power source from the pre-amp from my TV to the basement (now 50-60' between pre-amp and pwer supply), and then fed the output from the pre-amp into a powered 4 wasy splitter (for the remaining 40-50'), it would boost the signal strength to the TV and solve the fluxuating CBS signal. Truth be told, I lost CBS completely, though all other stations signals were better. I posted over at another forum and someone thought that it might be the signal is too strong, which may be the case. Based on TVFool's analysis of my location, I should be able to get away with an indoor antenna for most stations except FOX, but I found I had to do a lot of pointing to get each channel when the antenna was inside the house.

I do forsee CBS getting better as they transition from VHF to UHF on Feb. 17, 2009, however my NBC station is converting from UHF to VHF and is farther away, so I am worried about how that will play out.

Anyway, any suggestions on how to improve. Also, I have not installed the grounding clamp yet, I don't have anything to ground to other than the cold water pipes. Should I just ground to that or should I go buy a grounding rod and drive it into the ground and ground to that. Like I said, newbie here, so don't be affraid to point out my mistakes.

Do you have the screen on the DB2? If so , where is it pointed?

Hey guys,

I did my homework and finally settled on a BD4 to install at my house. For those of you who own one of these, it came with a little rubber thingie that I assume is supposed to seal the connection. How in the heck does it do that? Also, does any one have any pointers on how to waterproof my connections?

TIA,
KC

You put it on the cable, before putting the end on. I did not use it. I ran tape on the connection up to the top, then sealed the top to the bottom on the unit with coax seal....

Do you have the screen on the DB2? If so , where is it pointed?

The front of the antenna is pointing in the general direction of WGAL (channel 8), south (screen is pointing towards the North). Seems to be the best mid-point so far.

I think this is the 2nd time I've heard of a DB2 pulling in a Low-VHF station, which still surprises me, considering many locations have major problems with a real Low-VHF antenna.

As for WGAL, you may get lucky, but it's likely that an upper VHF antenna will be needed. 7.5kW at an off angle probably won't leave much margin for error on a DB2 with about -18dB gain for 7-13.

Since 10 and 8 are almost in opposite directions, the CM2016 might be worth a look.

The front of the antenna is pointing in the general direction of WGAL (channel 8), south (screen is pointing towards the North). Seems to be the best mid-point so far.

Looks like you are aimed the best that can be done... i would have prolly gone with the DB4 instead, so close in price, but I think you will be ok after the analog shutdown, with the possibility for a VHF-HI antenna...

Looks like you are aimed the best that can be done... i would have prolly gone with the DB4 instead, so close in price, but I think you will be ok after the analog shutdown, with the possibility for a VHF-HI antenna...

Do you have a suggestion on the VHF-Hi antenna? I would prefer something small if at all possible.

Do you have a suggestion on the VHF-Hi antenna? I would prefer something small if at all possible.

I would be tempted to try a CM2016:
http://www.solidsignal.com/prod_display.asp?PROD=CM2016

I know that you want to use DB2, but maybe combining these or just the 2016 after the shutdown, the DB2 pointed 85 degrees and the 2016 pointed roughly 135 degrees...

OR a CM 2001 pointed 135 degress with a joiner that blocks UHF and passing VHF and the DB2 pointed at 85 degrees....

http://www.solidsignal.com/prod_display.asp?PROD=ANCM2001&xzoom=Large#xview

Another technical question. I use a Vista Media Center machine inbetween the TV and the antenna. Lately, my signal strength is bouncing even more than before, with PBS and CBS dropping off for a period of time (both towers are within 6-7 miles of my home), CBS is VHF and PBS is UHF. If I unplug the pre-amp, nothing comes through, when I plug the pre-amp back in. If I had to guess, it's almost like the pre-amp isn't sending a consistent signal through.

Any suggestions on troubleshooting the issue?

Thanks.

I recently hooked up my HD TV to this old antenna on the roof that was present when we moved there. Only two channels with there sub channels show up. On a analog TV I get many channels and even Toledo which is 60 miles or so. Attached are the antenna and my local channels.
Any opinions?

Thanks.

124631

124633

124632

that looks like a metro/suburban antenna (thats what I call those) that should be getting more than 2 channels on digital if the connections are all good; I assume you're using RG-6coax; if you haven't checked the connection at the antenna I would do that. Pointed SE you should be getting a number of channels. if you want more a rotor would have to be added. But I would check the connections first especially at the antenna and rotate it by hand back and forth to see if reception improves. If it doesn't then maybe an antenna upgrade would be needed.

Hi, I put together a coat hanger antenna in DB4 design. I am able to receive the big 4 channels. However, I am unable to get CW channel.

Q1. Is there any reason why it shouldn't have more 4 elements on each side? For convinience, I would like to have the antenna longer with 5 or 6 elements on each side, but not wider.

Q2. I am having trouble getting the channels I want due to the orientation of my rented condo. Please read about my condo orientation below (image attached), and suggest me ways to get better signal (either through better antenna deisign or any other idea).

I am about 15 miles away from the tv towers. I live in a rented condo. I cannot put anything on the roof. However I can probably clamp something to the balcony railing which is on the 13-degree side (refer the attached image). The red one is my condo, and the yellow ones are the neighbouring ones, which obstruct a clear line of sight to the towers.

The big 4 come in at about 13 degrees angle and CW comes in at about 3 degrees angle.

I cannot clamp the antenna to face the direction of the towers. The other condos obstruct a clear view (unless, ofcourse, if I can offset it and clamp it cantilevered. But it is not allowed by the HOA).

What works is this. I just place the antenna against the railing. ie, instead of facing the towers, the antenna's face is parallel to the LOS. I get the big 4 easily at about 75%, but not CW.

FYI, the big 4 are transmitting at 1MW and CW is transmitting at 125KW.


Thanks.

Alright sounds like it might work better than the 4228. Thanks

Maybe now, but maybe not after February when a lot of channels will be moving. Take a look at your TVFool and the gains here : http://www.hdtvprimer.com/ANTENNAS/comparing.html

What works is this. I just place the antenna against the railing. ie, instead of facing the towers, the antenna's face is parallel to the LOS. I get the big 4 easily at about 75%, but not CW.


I looks like you are receiving the big 4 using a reflection. I'd try moving the antenna left or right while still aiming in the same direction and/or rotating slightly in another location to see if you get lucky with CW.

Below is the result from tv fools. If you mean 1Edge/2Edge by reflection, you are right. Would a DB8 work. I cannot move this antenna beyond the perimeter of my condo. Again, can I modify my DIY DB4 antenna to include more elements to increase the gain?

Network NM(dB) Pwr(dBm) Path Dist Color
CBS 44.7 -46.2 2Edge 14.0 Green
Fox 44.4 -46.4 1Edge 13.5 Green
NBC 44.2 -46.7 2Edge 14.5 Green
MyN 43.3 -47.6 1Edge 13.5 Green
ABC 41.8 -49.1 2Edge 14.0 Green
PBS 37.5 -53.4 2Edge 14.0 Green
PBS 36.7 -54.1 2Edge 13.9 Green
CW 33.8 -57.0 1Edge 14.9 Yellow


Noise Margin (NM): Higher the better
Predicted signal Power(dBm)
Path: LOS, 1Edge(Single edge diffraction), 2Edge(Double edge diffraction)

that looks like a metro/suburban antenna (thats what I call those) that should be getting more than 2 channels on digital if the connections are all good; I assume you're using RG-6coax; if you haven't checked the connection at the antenna I would do that. Pointed SE you should be getting a number of channels. if you want more a rotor would have to be added. But I would check the connections first especially at the antenna and rotate it by hand back and forth to see if reception improves. If it doesn't then maybe an antenna upgrade would be needed.

Thanks I'll check out those roof connections and rotate it a bit. It's directed
true north.

Thanks I'll check out those roof connections and rotate it a bit. It's directed
true north.

If you look at the antenna as an arrow, the point is away from the signal.
The tail, the vertical V would point toward the signal.
So if your antenna is truely pointing north, probably why you only get 2 stations.

I played around with the Pwr (dBm) figures for the incoming signal for the digital transition. I plotted these for before and after to see how I would be impacted.

In reviewing, it appears that it will be pretty much a gain for me, expect for two channels. I was quite surprised to see a gain of 18.70 dBm on a channel.

1) How much of a rise in signal strength is normally required to have any impact on your TV viewing? I think you need to see about 1.5 or so more to see on increase with the onboard TV diagnostics.
2) Am I approaching this correctly? In other words, can I take the numbers from TVfool and use this as a baseline?

Receive signal levels (dBm) in TVFool do NOT include attic/indoor loss, antenna gain
and balun/cable loss, which vary quite a bit with frequency. So to compare relative chances
of success, include (at least) these factors prior to Preamp (or Tuner if no Preamp).

I constructed an Excel spread sheet to do this:
http://www.avsforum.com/avs-vb/showthread.php?p=10961518&highlight=radio+mobile#post10961518

Most combo antennas have more gain at UHF than VHF...check specs and hdtvprimer.
A good balun may have 0.5 dB loss at VHF and 1.5 to 2.5 dB at UHF.
And refer to coax loss curves....

On the other hand, VHF channels tend to be more susceptible to man-made noise,
something that is not included in most propagation prediction programs....

PS: A "fair" comparison of DTV to Analog would require reducing analog dBm level by about 12 dB
to account for DTV coding improvements and Peak (Analog) vs Average (DTV) measurements.
But it appears that you were comparing DTV Before to DTV Post-Feb2009 (correct???).

=======================================
WILX (Lansing) is now on UHF Ch57 (43.4 kW ERP) and will take over VHF Ch10.
FCC TVQ dBase (erroneously????) says Ch57 has a 0 meter high tower and 291.9 meter
for DTV Ch10. This would seriously diminish TVFool's signal level results.

Fol. shows approved Change Proposal for 14.3 kW with a power increase request for 30 kW:
http://www.rabbitears.info/ss/
Use pull down menu under "AREA" to find Lansing.

CH11 and CH13 (Toledo) are relocating from UHF to VHF with power increases granted.
[To see which power TVFool is using, click on station callsign in the on-line report.]

So CH10, 11 & 13 (and many other DTV stations) could improve even further....
and reduction of adjacent/co-channel interference from Analog helps even more....

Hi,
I have two coaxial cables, which are about 20 and 25ft. One of them came with MANT940 antenna and the other I bought it off the shelf. The off-shelf antenna doesn't work properly and I get a weak signal. The cable with MANT940 works perfectly.

My questions:
1. What parameters make a good antenna? Is it the overall capacitance or resistance/impedance or both?
2. What should these parameters be? High/Low.
3. Can you suggest me a good cable which worked for you. I am looking for a 25ft. long cable to connect the antenna to TV. A link would be helpful.

Update:
Phillips cable's resistance is 2.6Ω and capacitance is 1nF per 20ft, so about 0.13Ω/ft
The other cable's resistance is 3.3Ω and capacitance is 1nF per 25ft, so about 0.132Ω/ft

The characteristics of both seem to be the same, except for the 2nd one's increased length. The 2nd one has RG59U written over it. So basically, both are RG59/U cables.

Am I right? Is this cable that bad, just because of the difference in its length?



Thanks.

The cable with MANT940 works perfectly.


You have a defective cable.

The MANT940 has a preamp. That preamp should mask small the differences between your two cables. The fact that one cable works and the other doesn't points to a defective cable or connector.

Hi,
The 2nd one has RG59U written over it. So basically, both are RG59/U cables.


I not a cable expert by any means. For a short run, RG59 is probably OK, but RG6 is much preferred for antenna / RF use. You can google the term "RG6" and there are links which explain the differences and where the original terminology came from. RG = Radio Guide -- A term the government used. 6= the page number that the specification for that particular cable was on.

Good to know the history.

1. I have white coaxial cables from my old place, which were laid by Cox for digital cable TV. There is nothing written over it. What could be these cables. "RG 6", or "RG6 Quad". They are thick and I can't make out the difference, without cutting the cable.

2. I am trying to connect an antenna to the converter box, with a 25ft cable. I know "RG6 Quad" is one of the best, but I want a realistic opinion, if RG6 would suffice. The reason is, I am buying a bunch of antenna supplies, and the site which has one doesn't have another. One site has everything, except cheap "RG6 Quad". So, I am settling for RG6.

3. I cannot drill holes, so I intend to use a "Flat coaxial coupler cable", for getting the cable inside. Alternatively, I want to use a thin coaxial cable which comes with converter boxes. What will be the effect of the signal if I do that. Would this thin cable be a major bottle neck, or will there be slight deterioration in the signal quality? I don't know the type of such cable (may be a RG 179/U), and if so I am not sure if it would block any frequencies. For OTA DTV, I would require something <1000 MHz).


Thanks for your help.

I don't think there is a huge difference between RG-6 and RG-6 quad. The "quad" refers to the fact that there is usually twice as much sheilding. I think I read somewhere that regular RG-6 provides about 60% sheilding and RG-6 Quad is supposed to be about 90% shielded. I have also read that one manufacturer's "quad" may be better than another manufactuer's.

Another thing to be aware of. Most RG-6 (and RG-59) cable has a steel center conductor which is copper coated on the outside. You can easily see this if you look at the end of the center conductor under a bright light with a good magnifying glass. You can buy a version that has a solid copper conductor. I don't think that the solid copper version is necessarily needed. One exception is that some mast mounted pre-amplifiers get their DC power from a "Power Injector" which is located inside near the TV. Some of these will not work well with the steel conductor RG-6. The copper coated steel may carry the RF signal just fine, but the resistance is too high for the DC current needed by the pre-amp.

Only single shield, braided coax has shielding in range of 60-80%....like old RG-59.

Some dual shield RG-6 has TWO braided shields (total of about 90-95%),
whereas the better dual shield RG-6 has an aluminized mylar "wrap"
inside a braided coax, providing (nominal) 100% shielding.

Quad shield takes this to the next level, such as when you are within a couple miles of other transmitters.

As a cost compromise, Belden now makes Triple shielding RG-6 with mylar/braid/mylar.

BTW: Percentage numbers usually only apply to the braid portion(s), since mylar should be 100%.
The meaningful measurement is isolation versus frequency....

Thanks for the clarification. I am just a "dabbler" in all of this and have done a lot of reading just in the last week or so. So, after a while, all the facts start running together.

P.S. - What does the U or /U stand for as in RG59U ?

I think /U means Universal Application, based on equipment installation indicators found
in MIL-STD-196E, "Joint Electronics Type Designation System".

MIL-C-17F thru MIL-DTL-17H provide an explanation of the new all-numeric part number system,
but doesn't explain the meaning of /U.

=========================================
The original MIL-C-17/2 (7Sep1955) presumably defined RG-6/U (spec no longer on-line).

MIL-C-17/2A (Rev A, 24Apr1978) defined the revised RG-6A/U number, but did not explain the /U....

MIL-C-17/180B (Rev B, 20Feb1994) superseded MIL-C-17/2A, but deleted any mention of RG-6 number.
[Understandable given "RG-6" was no longer being used to describe a specific cable construction.]

There are only minor detail differences in the above specs, each describing a dual braid shield construction,
with each shield having 95% coverage (hence both provide up to 99.75% total coverage).

So if you see a cable with anything other than dual braid shields, it doesn't meet the specific construction
requirements found in the Mil Spec.....it's probably BETTER....since aluminized foil provides 100% coverage:
http://www.belden.com/pdfs/TechInfo/TechReliable.htm

So don't try to read anything into whatever letters the manufacturers pull out of their hat to modify "RG-6".

==========================================
MIL-C-17/29C defined RG-59B/U (note they forgot to increment the Rev letter to C!!!).
It was superseded by MIL-C-17/184, which deleted all references to RG-59 numbers.
Construction is single shield with two alternative shield constructions with either 94.4% or 96.7% coverage.

Are rabbit ears the pinnacle of indoor VHF reception? I've been trying to find an alternative to rabbit ears, but there doesn't seem to be one. Since there are a myriad of different kinds of UHF antennas out there, it puzzles me that the only thing they've come up with in the past 50 years for VHF is rabbit ears. From what I've read, rabbit ears are not particularly effective, so what gives? Is there anything available that might be more effective for indoor VHF reception?

Which VHF channels are you trying to receive??? Check your www.tvfool.com prediction....
Can we limit it to only Ch9 and Ch11 in the VHF-Hi band???

Currently, only KQCK-DT (Ch11) and KO5MD-DT (Ch5) are potentially receivable
DTV in the VHF band. But would require a moderate to high gain OUTDOOR antenna.
Do you really need these non-network stations????

Currently strong analog KBDI-TV (Ch12) is adjacent to weak KQCK-DT
(Ch11) and KPXH-DT (Ch13), which can make them difficult to receive.

Post-Feb2009, Analog KBDI-TV (Ch12) moves to Digital KBDI-DT (Ch13),
making it easier to receive KQCK-DT (Ch11).
However, analog KBDI-TV (Ch13) will be 40 dB stronger than low power
KPXH-DT (Ch13) and hence will block reception.

Post-Feb2009, Ch7 and Ch9 convert to DTV and should be readily receivable with RabbitEars.

I would also be careful to avoid using high gain Preamps:
http://www.avsforum.com/avs-vb/showpost.php?p=15005797&postcount=8185

========================================
Back to your question....yes you could mount a VHF-Hi antenna in the attic (if available).

Or construct a DIY Yagi using a Folded Dipole, Reflector and Director elements:
http://www.wfu.edu/~matthews/misc/dipole.html
The bandwidth is only about 1 channel in VHF-Lo band and maybe 3 channels in VHF-Hi band,
so they aren't optimized for full-band use like a commercial antenna....
For Ch9 and Ch11 reception, cut the lengths for Ch10.
Also a good design exercise to see how big a "REAL" VHF antenna needs to be.
Anything smaller than the Folded Dipole would have NEGATIVE GAIN....

For extended VHF band coverage, a DIY LPDA (Log Periodic Dipole Array) would be
the next step up....requiring even more room.....

If attic is not available, perhaps you could attach it to the ceiling...or under a rug????
[You didn't say it had to look good....]

You also could construct a DIY Loop antenna by scaling up the size of a UHF loop
by 3 or 4 times....It can be circular, square or even rectangular....
VHF Loop (a simple piece of wire) could be scotch taped inside a window more or less
looking towards the desired tower. You'll need a 300 to 75-Ohm Balun Transformer.

======================================
Kerry Cozad (Dielectric Antennas) measured the gain for some REAL antennas.
For VHF-Hi band, CM-4228 8-Bay Antenna performed quite well, blowing away RabbitEars....
I have one in an upstairs closet.....

Which VHF channels are you trying to receive???

Currently, just channel 11; but post-transition 7, 9, 11, and 13. None of these should be a problem except for 11 since it is a good 60-70 miles away. I currently get very marginal reception of channel 11 (KQCK-DT) with a Terk HDTVa antenna (basically rabbit ears with an internal 10db amplifier).

Currently, only KQCK-DT (Ch11) and KO5MD-DT (Ch5) are potentially receivable DTV in the VHF band. But would require a moderate to high gain OUTDOOR antenna. Do you really need these non-network stations????

Well, it's a matter of want not need. After all, we're talking about TV here, so there's really never a need, but more channels is alway preferable to less.

Back to your question....yes you could mount a VHF-Hi antenna in the attic (if available).

I live in an apartment, so I don't have an attic nor do I have a deck or patio, but I am on the third floor of a three story building, so that helps. That being said though, I'm more concerned with function over form. I've considered buying a Winegard HD-1080 (http://www.winegarddirect.com/viewitem.asp?p=HD-1080) antenna since it is supposed to do better on VHF-hi than most of it's competitors. However, I read one review that said it would be less effective than rabbit ears, so I guess that's a no go.

Or construct a DIY Yagi using a Folded Dipole

This sounds like an interesting option. I think I'll give it a try.

You also could construct a DIY Loop antenna by scaling up the size of a UHF loop by 3 or 4 times....It can be circular, square or even rectangular....VHF Loop (a simple piece of wire) could be scotch taped inside a window more or less looking towards the desired tower.

Wow! Thanks for all of these suggestions. I've done a lot of digging and haven't been able to find much in the way of alternatives. I appreciate your comprehensive response.

ALTERNATIVE VHF ANTENNAS - I - for Indoors/Closets/Attic/Balcony:

Back to your question....yes you could mount a VHF-Hi antenna in the attic (if available).

Or construct a DIY Yagi using a Folded Dipole, Reflector and Director elements:
http://www.wfu.edu/~matthews/misc/dipole.html
The bandwidth is only about 1 channel in VHF-Lo band and maybe 3 channels in VHF-Hi band,
so they aren't optimized for full-band use like a commercial antenna....
For Ch9 and Ch11 reception, cut the lengths for Ch10.
Also a good design exercise to see how big a "REAL" VHF antenna needs to be.
Anything smaller than the Folded Dipole would have NEGATIVE GAIN....

For extended VHF band coverage, a DIY LPDA (Log Periodic Dipole Array) would be
the next step up....requiring even more room.....

If attic is not available, perhaps you could attach it to the ceiling...or under a rug????
[You didn't say it had to look good....]

You also could construct a DIY Loop antenna by scaling up the size of a UHF loop
by 3 or 4 times....It can be circular, square or even rectangular....
VHF Loop (a simple piece of wire) could be scotch taped inside a window more or less
looking towards the desired tower. You'll need a 300 to 75-Ohm Balun Transformer.

======================================
Kerry Cozad (Dielectric Antennas) measured the gain for some REAL antennas.
For VHF-Hi band, CM-4228 8-Bay Antenna performed quite well, blowing away RabbitEars....
I have one in an upstairs closet.....

ALTERNATIVE VHF ANTENNAS - II - for Indoors/Closets/Attic/Balcony:

I should also mention the Gray-Hoverman SuperAntenna and SuperSized 4-Bay Antennas
that are getting a lot of attention in the DIY UHF Antenna thread:
http://www.tvtechnology.com/article/68820
http://www.avsforum.com/avs-vb/showthread.php?t=798265

Although intended for UHF, like the CM-4228, some G-H versions have usable Hi-VHF band gain,
(similar to simple RabbitEars)...but a lot more than most typical UHF-only antennas.

If you search the thread for "VHF", you'll also find that removing the reflector on a 2-Bay
antenna provided "usable" Hi-VHF band gain. [This trick probably works for 4-Bay as well.]
Unfortunately, it allows UHF multipath to come in from the back of the antenna....

Post-Feb2009, more and more stations will be going to Circular Polarization to support
Mobile/Handheld robust waveform upgrade, as was discussed in the DIY VHF Thread:
http://www.avsforum.com/avs-vb/showthread.php?p=15039143

Not sure which antenna thread to use. If this is the wrong thread let me know.

Question, has anyone tried any of the new commercial Winegard High Band VHF/UHF combo antennas? They are all pretty new as far as I know, but hey I could be wrong.

If you need a list of the ones I am talking about let me know or this is the correct thread.Up here in Canada we'll have a few more years of VHF-LO stations than you folks in the USA will, but for people who want to put up a combo antenna in the post-February, 2009 period from what I can see Winegard has put together a good package on first glance. They are selling the new HD7697P and HD7698P VHF-HIGH/UHF combos, which they claim have a flat bandwidth response on VHF-HIGH (unlike their dedicated VHF-HIGH YA-1713 antenna that really loses steam on Channel 13). VHF-High gain is up to about 12dB, and UHF gain goes up to about 13 or 14 dB too. As people try them out and maybe model them by computer we might be seeing a new prescription for those wanting a combo.

As for me, I'm still counting on VHF-LO stations for a few more years so I'm sticking with my Channel Master Quantum 1111 VHF/FM along with my Gray-Hoverman for UHF. I'm building my second SBGH to join the 2 as a DBGH for getting Seattle and Tacoma stations from my location southeast of Vancouver, BC.

I should also mention the Gray-Hoverman antenna that's getting a lot of attention
in the DIY UHF Antenna thread:
http://www.tvtechnology.com/article/68820
http://www.avsforum.com/avs-vb/showthread.php?t=798265

Although intended for UHF, like the CM-4228, some G-H versions have usable Hi-VHF band gain.


I should clarify that before everyone starts running to digitalhome.ca with the same old question, heh. The Gray-Hoverman is a great UHF antenna design with very high gains available. And like Doyt Hoverman said, its beauty lies in that there are only two electrical connection points on the whole antenna. But the GH UHF antennas dont have any VHF-HI net gain. In fact the net gain is negative for the VHF-HI channels. (there is some raw gain available, but that would only help those in very noisy atmospheric conditions) Some who are very close to VHF-HI stations have reported that they have been pleased with the reception on the UHF GH. Of course, they could probably pick up those stations with anything. Using the UHF GH with a separate VHF-HI (or VHF-HI/VHF-LO) antenna via combiner or a CM0264 preamp is a great option, thats what I do.

There is a GH-4 VHF-HI version available, for VHF-HI only, with some very nice gains. But keep in mind, its a large antenna. My 20% smaller fractalized version of it is still 57"Wide by 87"High.

For decent UHF and VHF-HI reception in one antenna, I would recommend building mclapps 4 bay forward swept bowtie, 9 1/2" over 9", 15 inch reflector to element spacing, with a 36" to 44" forward swept reflector. Its harder to build than a GH, but it does have VHF-HI gains similiar to the RS VU-90. Directions for it are also found in the above avsforum thread.

ALTERNATIVE VHF ANTENNAS - III - for Indoors/Closets/Attic/Balcony:

Here's a link to (mostly UHF) gain curves (note gain in dBi = dBd + 2.15 dB):
a. 2-Bay with Screen Reflector
b. Original 4-Bay Hoverman without Reflector (no more Hi-VHF gain than a dipole)
c. Original 4-Bay Hoverman with "stick" Reflectors (my old one is stored in the garage)
d. Original 4-Bay Hoverman with Screen Reflectors
http://www.qsl.net/va3rr/hdtv/hoverman.htm

And a link to the Gray-Hoverman Superantenna webpage:
http://www.digitalhome.ca/ota/superantenna/

FYI: Here are the Hi-VHF gain curves (per range measurements) for some of
<mclapp's> super-sized 4-Bay antenna designs. Winegard type "stick reflectors"
works a lot better for VHF than C-M type screen (removing it may help???).

I added the CH07-CH13 scale to <mclapp's> charts for easier understanding....

Yeah, the Winegard stick type elements also have the advantage of being potentially easier to build and more durable than a bow tie.

And a link to the Gray-Hoverman Superantenna webpage:
http://www.digitalhome.ca/ota/superantenna/

Also check out the digitalhome.ca forum for tweaks on that original version.

FYI: Here are the Hi-VHF gain curves (per NEC simulations) for some of
<mclapp's> super-sized 4-Bay antenna designs. Winegard type "stick reflectors"
works a lot better for VHF than C-M type screen (removing it may help???).

Those graphs are from actual tests not NEC simulated but the NEC simulation shows very similar results.
The reason that the stick style appears to work better has more to do with the driven element size and spacing than reflector style.
Using a screen of the same size (width) as a rod reflector works just as well. A whisker style cut to the right length will work just as well as a flat element type with the larger reflector.
Removing the factory small screen may work better for some VHF-HI channels on a 4221 but not better than a larger (36" wide) screen or series of rods (even threaded rod).

Kerry Cozad (Dielectric Antennas) measured the gain for some REAL antennas.


The gain figures in those charts are computer simulated Raw gain numbers.

Kerry Cozad performed actual measurements on REAL antennas
(unlike most any other gain figures you'll see):
https://secure.connect.pbs.org/conferences/technology/2005/Sessions/TC05_43.htm
http://www.dielectric.com/broadcast/pdf/Measured%20Performance%20Parameters%20for%20Receive%20Antenn as%20.pdf

Hi,
I have built a db8 antenna and it is fine for one TV. However, when I use it to extend it to another TV using a splitter and about a 75' RG6 cable, the signal deteriorates. I want to do two things, use a preamp to improve the signal and then a distribution amplifier to boost the signal for the second TV.

1. Would this work? I heard that for digital OTA, the signal can only be improved with a better antenna.

2. Can someone suggest me a preamp, where I don't need to run a second cable for powering up the preamp? Something which will inject the power into the coax-directly will be better.

Any other suggestions for my situation?

Equipment:
1. Zenith DTT 901 and Echostar TR-40CRA

2. Can someone suggest me a preamp, where I don't need to run a second cable for powering up the preamp? Something which will inject the power into the coax-directly will be better.

Virtually all preamps run power up the coax.

You won't need both a preamp and a distribution amp. Either one will work.

Theoretically, a preamp provides slightly better performance than a distribution amplifier.

A preamp needs to be selected so that it doesn't overload. One such product is the Winegard HDP-269, but it can overload if you are close to the transmitters. Yet if you are that close you wouldn't need a preamp at all.

Kerry Cozad performed actual measurements on REAL antennas
(unlike most any other gain figures you'll see):
https://secure.connect.pbs.org/conferences/technology/2005/Sessions/TC05_43.htm
http://www.dielectric.com/broadcast/pdf/Measured%20Performance%20Parameters%20for%20Receive%20Antenn as%20.pdf

He performed real measurements of antennas but that plot is not the plot for the real measurements.
Here is a quote in the summary of that report

"Only a small sample of the measurements made is
presented in this paper. Measured gains will be
presented at the NAB Engineering Conference, as
they were not available at the time of writing of this
paper, as well as additional pattern analysis data."

The numbers in that plot are the raw gain numbers that you would get if you were to run those antennas in computer simulations.

I have found several good articles online about antenna spacing. I have also seen many good posts on the subject in various forums. I still have one question that I can't find an answer to and I am hoping someone here knows the answer.

Depending on the frequencies involved, the spacing needed to eliminate a pair of antennas from interfering with eachother can be as little as 14 inches for upper UHF and as large as 72 inches for upper VHF and FM.

I can not find, however, if this is the spacing between the active elements of the two antennas or if it includes the reflectors also. In my case, I have 4 antennas that I am installing next week. The top antenna will be a 91XG in which the main horizontal beam will be 43 feet above the ground. Underneath the 91XG will be a Funke psp.1922 pointed in nearly exactly the same direction. The 91XG will be used to pull in all UHF channels to the east while the Funke will only be used to pull in channel 11 (a Jointenna will be used to combine the channel 11 output of this antenna with another Funke pointed WNW that will pull in channels 7 and 9). I know that if the antennas are too close together, they will interact with eachother and cause interference. Since channel 11 is the longest wavelength, I need only to space the antennas far enough apart to satisfy its frequency. Thus, I need to place the two antennas about 4'-8" apart.

The question that I am asking here is:

Is the 4'-8" measured from the active elements and thus, the main horizontal beam, or is the 4'-8" measured from the top of the Funke reflector to the bottom of the 91XG reflector? If I need to measure from the reflectors, this will increase the vertical distance needed by several feet.

Along the same lines, the Funke will be attached as close to the top of the tower / bottom of the mast as possible. The Funke has the rear reflector that is fairly deep. If I mount the antenna very close to the top of the tower, will the tower interfere with the antenna reception? Will it affect the reflector's work in any way? Should it be a certain distance above the top of the Rohn 25G tower?

I only get one good chance to get this correct as I am renting a lift for a day to install all of the antennas, amps and cables.

Thanks for any help you can give!

Bill

Well, heres a good article on stacking antennas, that may apply to spacing distances too :
http://www.ifwtech.co.uk/g3sek/stacking/stacking2.htm

Notice the apertature shape of the yagi, its a horizontal oval. A corner reflector on the yagi would probably make the shape more circular.

I would err on the side of more spacing, as long as its practical and strong.

Typically, antenna spacing is measured center-boom to center-boom for stacking, and distance between nearest horizontal elements for preventing interference.

Rule-of-thumb dictates around 36 inch spacing to prevent interference with uhf, 48 inches for hi vhf, and 60 inches (or greater) for lo vhf.

cpcat...

That is exactly what I was afraid someone would say. I need to keep the nearest horizontal elements 4'-8" apart to keep the interference away from the channel 11 Funke antenna? This would mean that the top of the rear reflector on the Funke needs to be 4'-8" below the bottom of the rear mesh reflector on the 91XG. Is this true?

Also, what about distance from top of the tower? Do I need to keep the Funke 4'-8" above the tower ot eliminate interference, or does the tower NOT interfere like the 91XG elements do?

Bill

Here's another good article re Stacked Antenna spacing:
http://www.grantronics.com.au/docs/StkYagis.pdf

Bear in mind that results to optimize single frequency performance (e.g. Ham radio)
must be taken with a handful of salt when designing for 2:1 UHF frequency range....

I'm not really looking to satck two antennas for added gain...I am looking at how far apart I need to place a UHF and a VHF antenna on the same mast to avoid interference from one another. I know that I need 4'-8" for channel 11 and less for all UHF channels, so that is the minimum distance I am looking at. The question is:

Is the distance measured from the center horizontal boom or from the rear reflectors?

the second question is whether or not I need to consider interference from the Rohn tower itself. Do I need to be 4'-8" above the top of the tower / bottom of the mast?

Bill

I wouldn't worry about the tower.

The rule-of-thumb is just that. You may get away with narrower spacing with only a little/no loss of performance. It comes down to practicality in the end. For example, 36 inches is OK for hi vhf in my experience but I wouldn't push it any closer unless you absolutely have to. The upper vhf hi (say 10-13) channels should be more forgiving.

For spacing to prevent interference, measure from nearest horizontal antenna parts. This means reflector to reflector.

I'm not really looking to satck two antennas for added gain...I am looking at how far apart I need to place a UHF and a VHF antenna on the same mast to avoid interference from one another. I know that I need 4'-8" for channel 11 and less for all UHF channels, so that is the minimum distance I am looking at. The question is:

Is the distance measured from the center horizontal boom or from the rear reflectors?

the second question is whether or not I need to consider interference from the Rohn tower itself. Do I need to be 4'-8" above the top of the tower / bottom of the mast?

Bill


If they are dedicated antennas for two totally different bands like the ones you have the spacing isn't super critical. They shouldn't interact much if any at any reasonable spacing. Don't worry about any interaction with the tower either.

Where you run into problems is when the elements from one antenna or any other metal near by is the right length to be resonant with the other antenna. The tower is running vertical so it shouldn't bother a horizontal antenna a bit and a VHF antenna shouldn't have many elements that are resonant on UHF and visa versa. To be safe get what spacing you can but don't sweat it too much.

Hi,
I am trying to build a 8-bay antenna. It seems that it is just two 4-bay antennas. However, I want to know, how far apart do I need to separate the two sections? Any suggestions?

Thanks.

Hi,
I have a 3-way splitter very similar to this one
http://www.flickr.com/photos/thetorpedodog/2665312384/

How does a better one look? I use this one for combining signals from two antennas and also to split. It is OK so far, but am I missing out on some better ones?

Thanks.

I posted this in my local forum, but I thought it might be of interest to someone here:

I have mentioned many times on this thread my ongoing struggles to receive WNYT & WXXA OTA. The past few months have been particularly bad especially for WNYT which for most of that time was not receivable and when I could get it I was getting between one and two bars (out of ten) of signal strength. I would usually get two bars of signal strength on WXXA. I had been using a 30ish year old Radio Shack UHF/VHF combo 160 inch rooftop antenna that came with my house for VHF and a seperate UHF AD XG91 antenna combined through a CM 7777 preamp. UHF reception has been pretty good for the last year and a half or so, but it has been a struggle with VHF reception. I live in the northwestern Berkshire Mountain range, just to the east of Mt. Greylock, the highest peak in Mass. I sit about 49 miles east of the transmitters broadcasting the Albany networks. I have done a lot of research into my problem and decided to replace my Radio Shack with a new antenna. I narrowed it down to a Channel Master 3671 or a Winegard HD8200U. I decided to go with the Winegard and ordered it from Amazon because it was supposed to be UPS shippable and there's no place around here to get one. I was suprised at how long the box was at seven feet and it arrived with all but one staple removed and the antenna suffered a bit of cosmetic damage in transit including a few slightly bent elements that I was able to straighten without much trouble. All of the parts were there however and it wasn't much trouble to assemble. It was a bit bigger than I expected, about three feet longer than the Radio Shack it replaced. So I got it installed and aimed and checked my TVs. Well to my surprise my signal strength on WNYT and WXXA went from one to two bars up to a solid ten bars (out of ten) on both channels. I was quite amazed and wish I had replaced this antenna long ago. 6 and 10 analog now come in crystal clear and I'm even getting channel 2 out of Utica sound and snowy picture. Simply an amazing antenna and I recommend it highly to anyone on the fringe. I should be set now for the analog shutoff when channels move back to VHF. Very satisfied with this antenna.


I have a question to add to this though. My antenna is grounded to a ground rod where the coax enters the house. (The mast is not grounded seperately.) This is on the opposite side of the house lentgthwise from where my electrical service enters and this ground has been in place for probalby thirty or more years long before I bought the house. Also my DISH Satellite antenna is grounded on the opposite side of the same end of the house so i have potentially three grounding points. I have read that all grounds need to be connected by # 6 copper wire to the main service, but this is not the case on this house. The instructions that came with the antenna suggest grounding the mast also and using a lightning arrestor. My question is the copper line and the mast ground and the lightning arrestor really necessary or is it overkill?

My question is the copper line and the mast ground and the lightning arrestor really necessary or is it overkill?

Thats the way the new code has it. The old code was the way you have it now.

My antenna is grounded to a ground rod where the coax enters the house.
Thru a grounding block ? If so thats your lightning arrestor. If not, get one. Theyre only $3.95 or so at Lowes or Home Depot.

Thats the way the new code has it. The old code was the way you have it now.


Thru a grounding block ? If so thats your lightning arrestor. If not, get one. Theyre only $3.95 or so at Lowes or Home Depot.

Yes it is through a grounding block. Am i in serious danger if I leave things the way they are/have been for the last 30ish years? If so is this something that has to be done by an electrician? This would require quite a run of # 6 copper.

UHF reception has been pretty good for the last year and a half or so, but it has been a struggle with VHF reception. . . . . I have done a lot of research into my problem and decided to replace my Radio Shack with a new antenna.Are you still using the 91-XG for UHF?

HAHA
I asked the same question.
Yes, he is.

If so is this something that has to be done by an electrician? This would require quite a run of # 6 copper.

No, it doesnt have to be done by an electrician, since youre only grounding the wire to the outside of the electrical box somewhere, assuming your electrical box is already properly grounded.

Yeah, new #6 copper is pricey. If youre going to do it, I would shop or look around for used wire or discounts on already cut lengths.

No, it doesnt have to be done by an electrician, since youre only grounding the wire to the outside of the electrical box somewhere, assuming your electrical box is already properly grounded.

Yeah, new #6 copper is pricey. If youre going to do it, I would shop or look around for used wire or discounts on already cut lengths.

OK, so I just connect ground box on Sat to grounding box on antenna downlead to main power ground. As far as my box being grounded properly, I had my kitchen remodeled two years ago and added a sub panel and lots of expensive wiring for my kitchen. This was done by a licensed electrician per MA law and was inspected. I am assuming my service was grounded properly or someone would have said something??? I know that there is a large cable of wire coming out where the electrical meter connects to the house and goes down into the ground. I would speculate that it is about 3/8 inch thick and is stranded bare wire. It is greenish white in color so I believe it is copper. So I would just attach the # 6 to that wire somewhere, another grounding block perhaps. Does the # 6 just lay on the ground around the outside of the house?

Thanks for the assistance.

I know that there is a large cable of wire coming out where the electrical meter connects to the house and goes down into the ground. I would speculate that it is about 3/8 inch thick and is stranded bare wire. It is greenish white in color so I believe it is copper. So I would just attach the # 6 to that wire somewhere, another grounding block perhaps. Does the # 6 just lay on the ground around the outside of the house?

With the recent inspection, Im sure the box is grounded.

I certainly wouldnt cut into the wire from the meter. Clamping a wire to a bare exposed portion of it should be OK.

And that wire is ground, so no additional grounding block needed. The grounding blocks are just "lightning arrestors" for the coax cable which attaches to the antenna, nothing else.

You can bury that #6 wire if you like.

Also, the wire can be bigger than #6, but the hole on most grounding blocks will only accept #6.

Many thanks. Looks like a spring project. Spring comes late in these parts.

I am setting up a 4 antenna system in order to capture 2 different television markets. I am pointing a 91XG at 93 degrees in order to receive my local UHF stations, which all are from 89-97 degrees. Under that I am pointing a Funke psp.1922 at 89 degrees to receive channel 11.

Below the Funke will be another UHF antenna, perhaps a small Blonder Tongue single channel antenna for channel 31, which is weak and situated at 326 degrees. Finally, I have another Funke psp.1922 that will be aimed at 312 degrees in order to receive weak channels 7 and 9.

My plan was to use a CM 7777 to join the 91XG to the Funke for channels 7 and 9. Each of the other 2 antennas would have their own amplification, another 7777 for the channel 31 antenna and a Winegard AP-8275 for channel 11. These two antennas will be run seperately into the house. Once inside the house and past the preamp power insertion, I would add the single channels to the Main UHF/7&9 signal via a pair of jointennas with the channel 11 jointenna being first in the line. Once all channels are joined, they are sent directly to a 2 way splitter and off to the TVs.

I thought that this system would give me the highest performance I can get without the use of a rotor. I also thought that it would be best to run the antennas directly into their preamps, then into the house where they could be joined after the preamp stage. This, I thought, would give me amplification of the best available signals with the lowest amount of added noise. The amplification could then be used to overcome the loss induced by the jointennas.

I was just told that jointennas are usually mast mounted prior to the preamplification stage. If this is the case, wouldn't the signal going to the preamp be considerably less? Are jointennas a lossless joiner? Where should I install the jointennas? I thought my original idea would be best because the stronger amplified signal is actually meant to overcome losses due to long cable runs, splitter loss and jointenna loss.

Help!

Bill

I am setting up a 4 antenna system in order to capture 2 different television markets. I am pointing a 91XG at 93 degrees in order to receive my local UHF stations, which all are from 89-97 degrees. Under that I am pointing a Funke psp.1922 at 89 degrees to receive channel 11.

Below the Funke will be another UHF antenna, perhaps a small Blonder Tongue single channel antenna for channel 31, which is weak and situated at 326 degrees. Finally, I have another Funke psp.1922 that will be aimed at 312 degrees in order to receive weak channels 7 and 9.

My plan was to use a CM 7777 to join the 91XG to the Funke for channels 7 and 9. Each of the other 2 antennas would have their own amplification, another 7777 for the channel 31 antenna and a Winegard AP-8275 for channel 11. These two antennas will be run seperately into the house. Once inside the house and past the preamp power insertion, I would add the single channels to the Main UHF/7&9 signal via a pair of jointennas with the channel 11 jointenna being first in the line. Once all channels are joined, they are sent directly to a 2 way splitter and off to the TVs.

I thought that this system would give me the highest performance I can get without the use of a rotor. I also thought that it would be best to run the antennas directly into their preamps, then into the house where they could be joined after the preamp stage. This, I thought, would give me amplification of the best available signals with the lowest amount of added noise. The amplification could then be used to overcome the loss induced by the jointennas.

I was just told that jointennas are usually mast mounted prior to the preamplification stage. If this is the case, wouldn't the signal going to the preamp be considerably less? Are jointennas a lossless joiner? Where should I install the jointennas? I thought my original idea would be best because the stronger amplified signal is actually meant to overcome losses due to long cable runs, splitter loss and jointenna loss.

Help!

Bill

Bill,

If you're really looking for the lowest possible loss, go to www.tinlee.com It won't be cheap, but again, they will have the lowest loss and they can tune it to what ever frequencies you need.

~ryan

Absolutely agree about Tin Lee gear: very clean signal-wise, and does exactly what you need it to do.

I am researching on what I need for an antenna - I live in Racine, WI which is situated between Milwaukee and Chicago.

According to TV Fool:

http://img70.imageshack.us/img70/6981/picture1dl3.png

So I am about 30 miles South of Milwaukee and 55 miles North of Chicago's transmitters, with them being almost exactly 180 degrees apart from each other.

I've never done OTA TV but with the high quality of broadcast digital TV and the fact that I just don't watch that much TV I am ditching the cable with its ever increasing rates.

My setup, a digital TV - a Sony KDL32S2010 which is a 32" LCD (I'm just curious about what it has for an ATSC tuner and the sensitivity/quality of it). I am limited to an indoor antenna (No attic/outdoor installation for now, lets assume that). My final setup will likely be using (for a tuner) a TivoHD, DTV Pal DVR or a HDHomerun being fed into a small media PC. Again, I'm interested in the respective tuners each device uses.

Given that I don't own an antenna now and have never used OTA TV I don't know to look for in an antenna. I'm planning to pick up a CECB (For testing OTA reception and to later use on a non-digital bedroom TV) and an antenna soon. Would something like an Antennas Direct DB2 (Located in room) or DB4 (In a closet or hung on a wall behind a bookshelf or other object) perhaps be suitable? I've also been looking for a Radio Shack 1880 on eBay (If anyone knows where to find one or has one they want to part with. ;) ) as well.

I'm looking to be able to receive all my locals: ABC, NBC, CBS, FOX and PBS (This is what I worry about since they have two channels, one UHF with the SD subchannels and the other a VHF high channel that carries only their high def channel). What are my hopes for pulling in any Chicago stations? Being able to get WGN and WTTW (This would give me a huge amount of PBS content) would be great, any independents or Chicago major affiliates would be nice but not entirely necessary.

I thought my original idea would be best because the stronger amplified signal is actually meant to overcome losses due to long cable runs, splitter loss and jointenna loss.

Bill, your plan is far better than the typical installation.

Most people want a single preamp, hence the suggestion to mount Jointennas at the antenna.

dtloken,

Reliable reception from Chicago is a tough proposition at that distance from an indoor antenna of any kind. Beyond 20-30 miles, the antenna needs to be outside for good results. Typically, more than half of UHF signals -- channels 14-69 as shown in the "real" column of the report -- are lost by placing an antenna indoors or in the attic.

Milwaukee stations are a better bet given their stronger signals, but only in a wood-frame home. Brick, stucco or aluminum siding will block most or all signals. Placing the antenna directly in front of a north-facing window would help in that case, but not if the window contains low-E glass, which contains metallic oxide, or an aluminum screen.

The DB-4 is the best choice among the three antenna models you mentioned.

dtloken,

Reliable reception from Chicago is a tough proposition at that distance from an indoor antenna of any kind. Beyond 20-30 miles, the antenna needs to be outside for good results. Typically, more than half of UHF signals -- channels 14-69 as shown in the "real" column of the report -- are lost by placing an antenna indoors or in the attic.

Milwaukee stations are a better bet given their stronger signals, but only in a wood-frame home. Brick, stucco or aluminum siding will block most or all signals. Placing the antenna directly in front of a north-facing window would help in that case, but not if the window contains low-E glass, which contains metallic oxide, or an aluminum screen.

The DB-4 is the best choice among the three antenna models you mentioned.

A DB4, outside in a heavy pot would work, if you can "sneak" that past whoever is "baning" antennas....

A DB4, outside in a heavy pot would work, if you can "sneak" that past whoever is "baning" antennas....

Well, they're not banned it is just that my situation precludes the easy mounting of an antenna. I was thinking of cementing a post inside a pot which the antenna could be mounted on. At ground level however I would be worried about theft given where I live.

The window option is doable although fairly unsightly. Would a pre-amplifier be necessary if the outside option were to be made workable (given the cable run).

Well, they're not banned it is just that my situation precludes the easy mounting of an antenna. I was thinking of cementing a post inside a pot which the antenna could be mounted on. At ground level however I would be worried about theft given where I live.

The window option is doable although fairly unsightly. Would a pre-amplifier be necessary if the outside option were to be made workable (given the cable run).

What do you mean by easy mounting? Also, I take it that you are on the first floor? If you could concrete a 10ft pole in a pot, that would work nice...

The window option is doable although fairly unsightly.

Not necessarily. One man's unsightly is another man's beautiful. The Eiffel Tower was originally scorned as ugly.

The Eiffel Tower was originally scorned as ugly.

Probably because radio antennas were installed on it shortly after it was built!

Would a pre-amplifier be necessary if the outside option were to be made workable (given the cable run).

Probably not, unless the resulting cable run is more than 100 feet -- or the signals are split between two or more TVs. Most times it's best to see how well the antenna works by itself, then add a pre-amp if needed.

Solid Signal has advised that the new CM 4221 and 4228's are now available. The 4228's just came in today.

If the pricing wasn't higher than the old ones, I would probably order one for testing purposes (I may anyway).

If anyone can test the new models, I would be interested in the results.

It would be great if when someone does get the new CM4221 or CM4228, they would post pictures and detailed dimensions of it for modeling purposes.

I've attached my tvfool results. I'm in the SLC, UT area, ZIP 84096. I'm currently doing OK with a silver sensor in the garage, but I'm getting little dropouts I'd like to clean up. I'm interested more in after 2009 as channel 13 here will be moving back to VHF-HI. From reading around a bit, the CM4228 sounds nice, but I'm wondering if it's overkill? I was considering trying the CM2016 as it advertises 7-69 and I am reasonably close to the towers at 13 miles. It's also smaller and cheaper, which is nice for the wife.

I have RG6 running to the roof with a patch panel in the basement. I'll likely have 2 splitters in the system, but I see no need for more than that. I tried the monoprice.com outdoor amplified antenna with poor results. Without the amp, it's not strong enough, with it I overpower everything. And I expect the amp is the cheap noisy variety. So I want to move away from amps and a better antenna on the roof seems like just the ticket.

Any tips would be greatly appreciated.

I've attached my tvfool results. I'm in the SLC, UT area, ZIP 84096. I'm currently doing OK with a silver sensor in the garage, but I'm getting little dropouts I'd like to clean up. I'm interested more in after 2009 as channel 13 here will be moving back to VHF-HI. From reading around a bit, the CM4228 sounds nice, but I'm wondering if it's overkill? I was considering trying the CM2016 as it advertises 7-69 and I am reasonably close to the towers at 13 miles. It's also smaller and cheaper, which is nice for the wife.

I have RG6 running to the roof with a patch panel in the basement. I'll likely have 2 splitters in the system, but I see no need for more than that. I tried the monoprice.com outdoor amplified antenna with poor results. Without the amp, it's not strong enough, with it I overpower everything. And I expect the amp is the cheap noisy variety. So I want to move away from amps and a better antenna on the roof seems like just the ticket.

Any tips would be greatly appreciated.

The 2016 would be great (no need for the "expensive" and big 4228)[ another to consider is a DB4...], maybe maybe a distribution amp, with low gain if you are going to split more the once, but at those distances with LOS, anything outside will be great....

The 2016 would be great (no need for the "expensive" and big 4228)[ another to consider is a DB4...], maybe maybe a distribution amp, with low gain if you are going to split more the once, but at those distances with LOS, anything outside will be great....

Thanks! I know the 4228 isn't really all that expensive, but if it's not necessary, I can mount a smaller antenna and the wife will be happier.

I also just read in the local thread that Channel 13 is going to stay UHF now. I guess they realized that a lot of people were buying UHF only antennas as that's all they needed in the past. Thanks for the DB4 recommendation, it looks like a great antenna for my needs.

DB-4 for VHF

I discovered in the forums that I don't need VHF after all, the one station that was going to use it decided against it. So I went with the DB4. It's a little smaller and I think the wife will be happier with it.

If they do end up going VHF, I can add a simple antenna for 13 and join it to the system. I've been able to get their analog signal with rabbit ears, so I don't need much for them. If that doesn't work, I guess I'll have a DB4 for sale. :D

DB-4 for VHF????????????????????????????????????????????????????????? ???????????????????????????????????????????????????????????? ???????????????????????????????????????????????????????????? ???????????????????????????????????????????????????????????? ???????????????????????????????????????????????????????????

VHF 13, at just a few miles, I really do not think it will be a problem...

Ok, so say I do go with a DB4. Chicago and Milwaukee's transmitters are 180 degrees apart from each other in my location.

If I aim the antenna towards Chicago will the antenna pull in Milwaukee from the rear assuming the signal is strong enough? Should I consider a second antenna back to back with the first using an antenna combiner?

At those high signal levels, nearly anything metallic is going to pick up CH13....
Any of the 4-Bay antennas should do the job, whether A-D, W-G or C-M.

Also note extending screen size on CM-4221 increased VHF gain up to 10 dB:
http://www.avsforum.com/avs-vb/showthread.php?p=15129303

I need some help cleaning up my OTA signal. Specifically, I live in Grand Island, NY (Buffalo, NY). My problem is that I live about 1-2 miles from about 1/2 of the transmitters for Buffalo, the other 1/2 are about 30 miles away. I currentlly use a CM 4221 in the attic and have no problem recieving everything but the local NBC station (WGRZ). This station is notirious for being difficult to recieve and I have to add a preamp to recieve NBC reliably enough for my HTPC (HDHomeRun) to cleanly record my shows. However, the preamp overloads my TV input so i can't complete a scan. I've attached my tvfool results.

I need some advice on where to spend my $ to improve the reception and have a few questions....
1) NBC(WGRZ 30 miles) and CW (WNLO - 1 mile) are on adjacent channels, is this causing my problem? If so, how to fix it?
2) Would a YAGI type antenna help to isolate the two channels that only have 25deg of seperation in headings? If so, any recommendations?
3) My CM4221 has been dammaged due to several moves, I have taped together as best as possible, could this be causing the problems?
4) With the antenna mounted in the attic (on wood), do i have to ground the back CM4221 array? If so, how?

Thanks for all of the help, in advance!
-DrPyro

DrPyro, 2 possibilities:
take out the preamp and just amplify that one channel
leave in the preamp but just attenuate that one channel
Check out Tin Lee and ask them how to drop or boost the signal on only WGRZ while leaving the others as they are, depending on which option you choose. Personally I'd get rid of that preamp and amplify only WGRZ.

http://www.tinlee.com

Tin Lee gear is top quality and the staff are very helpful.

If I aim the antenna towards Chicago will the antenna pull in Milwaukee from the rear assuming the signal is strong enough?

Probably not. You could try to remove the reflector panels from the back of a DB-4 on an experimental basis. The "bowties" are bi-directional when used without the reflector. Be aware that this will reduce antenna gain, so it might not yield the consistent reception you're seeking from Chicago.

Should I consider a second antenna back to back with the first using an antenna combiner?

This may work, or it may not. You'll have to find out whether the two antennas will interfere with one another through a second experiment. If results aren't good, you have an alternative: Remove the combiner and install an antenna A/B switch at the TV. You'll need to run two coax cables, one from each antenna. Manual switches are cheap; remote-controlled switches are available from a few places for $30-$50.

I need some help cleaning up my OTA signal. Specifically, I live in Grand Island, NY (Buffalo, NY). My problem is that I live about 1-2 miles from about 1/2 of the transmitters for Buffalo, the other 1/2 are about 30 miles away. I currently use a CM 4221 in the attic and have no problem receiving everything but the local NBC station (WGRZ). This station is notorious for being difficult to receive and I have to add a preamp to receive NBC reliably enough for my HTPC (HDHomeRun) to cleanly record my shows. However, the preamp overloads my TV input so i can't complete a scan. I've attached my tvfool results.

I need some advice on where to spend my $ to improve the reception and have a few questions....
1) NBC(WGRZ 30 miles) and CW (WNLO - 1 mile) are on adjacent channels, is this causing my problem? If so, how to fix it?
2) Would a YAGI type antenna help to isolate the two channels that only have 25deg of separation in headings? If so, any recommendations?
3) My CM4221 has been damaged due to several moves, I have taped together as best as possible, could this be causing the problems?
4) With the antenna mounted in the attic (on wood), do i have to ground the back CM4221 array? If so, how?

Thanks for all of the help, in advance!
-DrPyro
1. Ch32 is only 1.2 miles away and will overload not only a Preamp, but also DTV input.
Adjacent Ch33 (and next adjacent Ch34) will be very difficult to receive due to Ch32.
And are ALSO very strong signals.....no need for a Preamp....

The very tough spec for the CECB boxes (NTIA Coupon) allow a STRONG undesired signal
to be no higher than 20 dB above the desired signal and 33 dB for weaker undesired signals.
Your situation is outside the CECB performance capability....and most DTVs are WORSE...

2. You need an antenna that can steer a deep NULL towards Ch32 to help equalize levels.
A 4-Bay, like the CM-4221, isn't very suitable cuz nulls are towards the SIDES:
http://www.hdtvprimer.com/ANTENNAS/cm4221.html

You need an antenna with deep nulls at about 25-35 degrees, such as CM-4228:
http://www.hdtvprimer.com/ANTENNAS/cm4228.html
CM-4228 also has a moderate amount of gain for Ch7.

Some yagi's can also do the job...more or less, but are iffy for Ch7:
http://www.hdtvprimer.com/ANTENNAS/comparing.html

3. Duct Tape??? You need good metal to metal conductivity....

4. No, indoor antennas, even in the attic, do not need to be "grounded".

====================================
You may find adding attenuation PRIOR to the Preamp will help, such as a couple of
2-way splitters or a variable RF Attenuator:
http://search.solidsignal.com/?site=com&q=attenuator&I1.x=0&I1.y=0
Even after removing Preamp, it may help to prevent overloading your DTV.

I GUESS the Preamp is helping (a little) due to strong Ch32 signal SATURATING
the input, so that the difference wrt Ch33 is less....but it should be removed.

=====================================
Filters won't work against adjacent channel without seriously degrading desired channel
wrt both attenuation, phase and ENVELOPE DELAY....which affects DTV more than Analog.
There is no such thing as an (affordable) brick wall filter....

Alright, so anyway. Someone gave me a crappy Magnavox CECB for free. I brought it to my mom's house (She has an aerial antenna on a 30ish foot mast, unknown antenna type/make, she believes it was a Channel Master) and was able to aim the antenna at Chicago and receive every major channel from Milwaukee and Chicago other than PBS 10 (Which is VHF).

AFAIK we had:

2, 4, 5, 6, 7, 9, 11, 12, 18, 20, 24, 26, 32, 38, 50, 58 plus a few non-English language channels (And another ION affiliate that I can't remember)

When aimed at Milwaukee I could get channel 10 but not all of the Chicago channels.

I am extremely impressed with that. I brought the box to a friend's house who has a Philips MANT410 indoors.

With this I am able to pull in 11 and 9 from Chicago, 5 and 32 from Chicago were comming in sporadically. I was able to pull in almost every Milwaukee station reliably. Count me as being extremely impressed here since at this location we are about 55-60 miles from the Chicago transmitters and 30 from the Milwaukee ones. I am going to order a DB4 and see how it performs from this location given how well the cheap Philips is working.

Holl_ands-

WOW, thanks a TON your post was very helpful. I have been reading a ton to figure these things out, but I'm slowly starting to understand. I'm looking for appropriately directional antenna now. Having played with some lasers/filters, some of the notch filters are very very narrow band, so i was hoping i could get something like that for the TV channels. Oh well...thanks again...

-DrPyro

I need to purchase a new antenna for the house I'm renting. I'd like to get an outdoor antenna for improved reception and place it in one of my spare bedrooms that I am not using. The bedroom is fairly large (about 14'x14') so I should be able to go up to about a 84" turning radius with my rotor.

I live in a fringe area with the closest broadcasting towers about 50 to 70 miles away. I have determined that I will only need digital channels starting at Ch. 7 and up after the transition in February. Currently Ch. 7 is one of the most difficult for me to receive so I need a good antenna that can receive at least VHF-Hi and UHF. I also have a pre-amp on my current crappy antenna.

I have considered the Channelmaster 4228 or 4228HD, but I understand that it is primarily a UHF antenna that happens to work fairly well for VHF-Hi. My concern with this antenna is that it may not have the range I need for Ch.7 and Ch.9 since I am so far from the transmitting towers. According to the literature, the CM 4228HD has a range of 60miles for UHF and 45miles for VHF-Hi.

I notice that for about the same money, I can purchase the VERY large Channelmaster 3020 which is a full VHF/UHF antenna. The literature says that this antenna has a range of 60miles for UHF and 100miles for VHF which should be sufficient to receive all of the channels needed when using my pre-amp. The only problem with using the CM3020 is that it has a turning radius of 95" which would be a bit too large to fit and rotate in my room.

Since I have been told that the longest members of a VHF antenna are specifically for the VHF-Lo channels, I was wondering if it would be possible to purchase the CM3020 deep fringe antenna and remove some of the longer members to reduce its size to fit my room without losing the VHF-Hi and UHF capabilities that I need?

I am hoping that someone who understands antenna construction better than I can answer this question.
Thanks,
medoug.

2. You need an antenna that can steer a deep NULL towards Ch32 to help equalize levels.


FWIW, here's a recent null test I conducted with a local analog station.
http://www.wtfda.info/showthread.php?t=2655

With DrPyro only 1.2 miles away from ch. 32, I'm not sure any antenna array could effectively null that signal, but it's worth a try. I live 3 miles away from the tower of another local analog LP on ch. 50, and by using the stacked array, I was able to decode WBXX-DT 50, Crossville, TN (@ 282 miles) during a time of some tropospheric ducting/enhancement.

Sometimes while DXing DTV, moving the stacked antennas just 2-3 degrees will determine whether I'm receiving DTV station 1 or DTV station 2, or whether I'm receiving DTV 1 or DTV 2 and/or an analog station on the same channel. Sometimes receiving a DTV station is more about nulling interference (co-channel, adjacent channel, multipath, etc.) than it is getting the strongest signal.

And here's another example for DrPyro in Buffalo, NY. I doubt I would have been able to decode these two Buffalo DTVs (WKBW-DT 38 & WIVB-DT 39 @ 431 miles) in my very high RF location (3-5 miles from the Indy antenna farm) without the nulling ability of the stacked antennas.

Steve

Since I have been told that the longest members of a VHF antenna are specifically for the VHF-Lo channels, I was wondering if it would be possible to purchase the CM3020 deep fringe antenna and remove some of the longer members to reduce its size to fit my room without losing the VHF-Hi and UHF capabilities that I need?

Having a large deep fringe antenna inside is not a good idea at all. The losses and multipath issues are huge. With renting a house rather than a condo or apt, you should be able to mount it outside. Ask the landlord.

Cutting the elements off a LPDA antenna, even the vhf-low ones is also not a good idea. The long elements do act as reflectors for vhf-hi to some exent and the antenna SWR is designed with those elements at their present size. Without computer modeling, its a wild guess as to what and how much to cut. You should save some money by buying a vhf-hi/uhf combo or separate antennas instead. If you have to mount indoors, I wouldnt be suprised that a smaller cheaper vhf-hi/uhf combo (or the CM4228) would out perform the CM3020 indoors.

the big question is: Why are they still selling these humongo monsters, when 95% of the U.S. won't have any V-Lo's? Mfgr's should melt down their existing inventory and start over...make V-Lo only antennas for the few areas that need them (assuming V-Lo will really work?)

If you have to mount indoors, I wouldnt be suprised that a smaller cheaper vhf-hi/uhf combo (or the CM4228) would out perform the CM3020 indoors.

O.K., I understand now that the CM3020 may not be the best solution for my situation. Part of the reason I was considering it was that I plan on purchasing a house within the next year at which time I would mount it on the roof or a tower.

I'd be quite receptive to buying a good vhf-hi/uhf combo instead of a monster vhf/uhf antenna, but unfortunately I haven't found anything in that category that can assure me of receiving all the digital channels I expect in my fringe area.:( (Channelmaster doesn't seem to be offering anything that gets me in the 60+ mile range for BOTH uhf and vhf-hi, and other brands don't seem to rate by milage.) Can anyone make a recommendation for such an antenna, perhaps from another brand? I'd like to stay under $100 if possible.

medoug.

P.S. I just verified on TVfool that I am 58-75miles from the towers I expect to receive digital broadcasts from.

the big question is: Why are they still selling these humongo monsters, when 95% of the U.S. won't have any V-Lo's? Mfgr's should melt down their existing inventory and start over...make V-Lo only antennas for the few areas that need them (assuming V-Lo will really work?)

I suppose so that people can still watch the LP stations on 2-6. We have one locally, which can barely be called a station, so I won't count that.

I have no idea while the Low-VHF monsters continue to be sold in the Southern California area. Ok, analog XETV will continue on 6 for those that want to bother with it.

I tried talking someone out of getting one such monster, but he couldn't believe that we weren't going to be using 2-6 locally for DTV.

Some want FM capabilities, but there are newer antennas that are not nearly as wide which can handle FM (such as the new CM Advantage line).

Maybe the real reason is to scare people away from upgrading their antennas. Since the FCC/government did not remove 2-6, the perception that outdoor antennas have to be the size of small boats will continue.

I see many "boats" on my drives locally and most of them are in very strong signal areas.

for MeDoug, you may want to consider separate high-band VHF and UHF antennas if you have the room in the attic. A ten element high band VHf ant. will have shorter boom length than the old all channel 2-69 models. Plus if memory serves me right, you should be able to buy separate hi-V and U antennas for less than what Winegard charges for one of their hotter hi-V/U combos such as the HD 7698 P. Although if it's going to eventually end up outside, Winegards have historically held up well, though others may want to chime in on this as far as recent years are concerned.

More on hi V - U ant discussion from 6 months ago click here (http://www.avsforum.com/avs-vb/showthread.php?p=13845261#post13845261)

Now, if you want to see some really old monsters...

Relics in Aluminum of Cañon City CO (http://nebraskamediadiscussionforums.yuku.com/reply/5826/t/is-it-wrong-to-admire-old-TV-antennas-.html#reply-5826)

For people in a Canadian border area you'll have the VHF-LO stations from up north for a few more years too. Out here on the west coast there are lots of Washington State residents hanging on to their big old VHF antennas for that reason to get the Vancouver and Victoria stations.

Having a large deep fringe antenna inside is not a good idea at all. The losses and multipath issues are huge. With renting a house rather than a condo or apt, you should be able to mount it outside. Ask the landlord.


Federal law says you dont have to ask the landlord, remember?? As long as it is in an area of your "control" and not in a common area, it can be done even at an apt, etc...I did it for 3 years at an apt in N Dallas. Sat Dish and outside OTA antenna...

I'm an old time TV/FM DXer from my old home in upstate NY back in the 70's. I am also a ham and have done just about every type of propagation mode from LF to microwave. So this is not new to me, but I have the bug to TV DX again due to the digital age and also because station ID is positive with a digital lock. Back in the day I had the king of VHF antennas...the Jerrold VIP-307 , and it was a monster! I forget what I used on UHF. I think it was an old RS yagi. Not bad, just not exotic. UHF was not what I was after back then. I was pulling stations fairly well at 100+ miles away (NYC) on a regular daily basis, and that was over a mountain range in lower Dutchess County and Putnam County. DX to Boston and Phili was fairly common. Also DC on occasion, and E-SKIP on low band was wild and crazy! I even pulled in Cali on CH. 2 F-SKIP during the solar peak. The preamp was also a Jerrold (forget the number). Analog DX was fun, but noisy. I know Digital will fail with high interference and noise, but a clear burst of signal that locks gives positive ID, so it sounds fun to get into TV DX again.

I got that bug again! It started when I built a new PC with an ATI HD Wonder card. The little antenna that came with it mounted in the attic was very good and pulled in a huge number of stations (now in SE FL) during tropo openings. I tried a Crapshack V/U antenna that did very badly in the attic (junk). I did a little homework and decided on a Delhi (not near the quality construction the old Jerrold had) VU-933SR. Why not a higher gain VU model? Well I liked the polar pattern better. I beam south to three different TX tower locations and the 933 pattern would be better to cover all of them. The gain is still good and I can add the VU-8PZ if I want a little sharper UHF performance.

Now I am getting ready to order all of the stuff I need to complete the system. I'm trying to decide on a preamp and could use some help. If anyone has some input on my system idea I would welcome the comments. Here is what I'm planning so far:

- Delhi VU-933SR
- Channel Master 9521A rotator (any good? anything better?)
- Winegard AP-8700 (or maybe an AP-8780)
- RG6QS all the way on less than 100' runs (have hardline but that is total overkill)
- 2 GHz 4-way splitter with -7.5 dB loss per tap (will bypass for times of DX)
- DTVpal DVR (as a main receiver...might try others eventually)

My link budget with the AP-8700 through the 4-way splitter comes out to: VHF-L +5dB, VHF-H +4dB, UHF +3 dB (or UHF +12 dB with the AP-8780). Preamp noise is calculated into these numbers. Without the splitter everything goes up 7.5 dB. I wonder if the extra gain on UHF using the AP-8780 (V +17 / U +28) would be a problem with overload. The nearest UHF station is 15 miles away, but I never point at it as the regular weaker stations I need to get are 34 degrees off of that. I wish the AP-8700 had just a little more UHF gain, but it might be enough. The max signal into the AP-8780 UHF input is rated at 30,000 uV. The AP-8700 is rated at 93,000 uV. What is the better choice here?

The antenna has gain of +6 dB VHF-L, +10 dB VHF-H, and +9 dB UHF. Not a real DX king, but I expect to get plenty during band openings. Oh...and due to lightning risk here on the Florida coast, I will keep the antenna just above roof level. Any suggestions?

for MeDoug, you may want to consider separate high-band VHF and UHF antennas if you have the room in the attic.

Yep.

And a good way to combine the uhf and vhf antennas is with the CM0264 preamp. 2 separate 300 ohm inputs, (one for uhf, one for vhf) and one simple 75 ohm output.

At your distances, you dont have to worry about the overload problems.

Rick,

Hey thanks for all the advice. Now you have me thinking of a few things. I was thinking about the CM7777. I thought the Winegard AP series was preferred, but I'll take your advice and get the CM instead. I wish they listed the overload specs, but a good experienced user suggestion is enough for me.

I already have the VU-933. The initial idea in getting this antenna was to cover three tower locations with one rotor setting for my locals (all at 180 deg). As it is, I get all the local UHF stations (up to 50 miles) with a little UHF antenna in the attic. During tropo I can get Miami stuff over 100 miles. I would not expect to watch Miami stations every day. That would take some major antenna height. West Palm is no problem.

I already have the RG6QS. Next time I buy some I'll try the tri-shield.

So this may not be the big DX setup I once had, but it should be fun enough. I get a huge amount of stations on tropo openings. Even up past Orlando and Daytona.

One more question. Is anyone doing digital on VHF Low Band. I LOVE low band! I hope it stays around. Knowing the FCC they would give it away to cordless telephones or something stupid like that.

Phil

Yep.

And a good way to combine the uhf and vhf antennas is with the CM0264 preamp. 2 separate 300 ohm inputs, (one for uhf, one for vhf) and one simple 75 ohm output.

At your distances, you dont have to worry about the overload problems.

Thanks for the input. No overload. Cool!

Maybe if I get serious I will go with the dedicated band antennas. This is a start.

Phil :cool:

Hello,
I was wondering if anyone had tried to use two db4's to pick up thier digital signals. The reason I ask is that I have about a 60 - 65 degree spread in the towers I am trying to recieve (according to tvfool and antennaweb).

I was thinking that I could direct one db4 facing the center of one half of the spread (toward the right 30 degrees) and then another facing the other 30 degrees. I would keep the antennas physcally distant by a few feet or so (thinking that they may interfeer with each other.

Then use a combiner to run the coax back to the TV.

Any thoughts on this.

By the way I can pick up all my major networks with some old 1990's rabbit ears with a round disk in between them (says optima on it). Buy my signal strength on the weaker channels is around 30% or so - the others upwards of 70%. I am thinking that just a better antenna such as the db4 would give me vast improvments.

Hello,
I was wondering if anyone had tried to use two db4's to pick up thier digital signals. The reason I ask is that I have about a 60 - 65 degree spread in the towers I am trying to recieve (according to tvfool and antennaweb).

I was thinking that I could direct one db4 facing the center of one half of the spread (toward the right 30 degrees) and then another facing the other 30 degrees. I would keep the antennas physcally distant by a few feet or so (thinking that they may interfeer with each other.

Then use a combiner to run the coax back to the TV.

Any thoughts on this.

By the way I can pick up all my major networks with some old 1990's rabbit ears with a round disk in between them (says optima on it). Buy my signal strength on the weaker channels is around 30% or so - the others upwards of 70%. I am thinking that just a better antenna such as the db4 would give me vast improvments.

Can you post your TVfool results? I am thinking that one DB4, should be enough, but I need to see the site stats first....

Can you post your TVfool results? I am thinking that one DB4, should be enough, but I need to see the site stats first....

Here is the tvfool.com results. I am planning on putting it in the attic - considering I can receive pretty good with rabbit ears.

Here is the tvfool.com results. I am planning on putting it in the attic - considering I can receive pretty good with rabbit ears.

FYI...the channel I primarly have issues with currently is the cbs station - 3.1. I can get it but the signal strength is down around 20% and sometimes to get it I have to give up two of the other major networks HD channels.

Here is the tvfool.com results. I am planning on putting it in the attic - considering I can receive pretty good with rabbit ears.

If at all possible, I would try for a roof install, attic installs are tricky and you loose 50%+ of signal right off the top.... The DB4 can be mounted on a sat dish mount and is not much taller then a normal dish......

FYI...the channel I primarly have issues with currently is the cbs station - 3.1. I can get it but the signal strength is down around 20% and sometimes to get it I have to give up two of the other major networks HD channels.

Ok, my thought is go with one DB4 (I think with 2 aiming in different directions, you could end up with bad multipath) and a Winegard HDP 269.. (this amp is lower on gain, and I have read here on AVS, that it does not overload easily, but you could also try a CM 7777, but I wonder if the stations at 18miles may overload it) Now I would try with the screen on the antenna, but if some of the off-axis give issues, you could try with the screen as well... I would aim at 200 degrees and fine tune from there.. (or if you take the screen off aim for 180 degrees and go from there)

BTW, I never did ask which of the stations and markets are you all trying to grab here? You are in a great spot to get a pile of channels!

If at all possible, I would try for a roof install, attic installs are tricky and you loose 50%+ of signal right off the top....

I know this but I assumed that since my rabbit ears sitting right next to the TV can pick up the channels then I shouldn't have a problem. Is this not accurate?



Ok, my thought is go with one DB4 (I think with 2 aiming in different directions, you could end up with bad multipath) and a Winegard HDP 269.. (this amp is lower on gain, and I have read here on AVS, that it does not overload easily, but you could also try a CM 7777, but I wonder if the stations at 18miles may overload it)

So you are saying to use two antennas - just not two DB4's? due to the mulitpath issue?[/QUOTE]


BTW, I never did ask which of the stations and markets are you all trying to grab here? You are in a great spot to get a pile of channels!

Just trying to get the channels South/SouthEast - in the Green and Yellow - maybe some of the Red if i really get into this antenna thing! (just cancelled satellite after realizing HD is free and I get good reception). But I have never recieved any of the red - analog that is.

I know this but I assumed that since my rabbit ears sitting right next to the TV can pick up the channels then I shouldn't have a problem. Is this not accurate?

It could work very well, but if you go on the roof, many of the other stations might just come in, you may get multi markets with ease... 1-2Edge at 50miles in Red is not that hard to get, with the amp, you very well could be very surprised... You said that you had satellite, well you could use the mounting from the dish for the antenna, if it is in a good spot, and even re-use the cable from the dish....



So you are saying to use two antennas - just not two DB4's? due to the mulitpath issue?
I would go with just 1 DB4 for the start, down the road you may want to add a VHF-HI antenna as well...


Just trying to get the channels South/SouthEast - in the Green and Yellow - maybe some of the Red if i really get into this antenna thing! (just cancelled satellite after realizing HD is free and I get good reception). But I have never recieved any of the red - analog that is.

That was what I figured, also this was pre-transition, correct?

You location is really good, I would love to be able to go after as many markets as you have close with the ease that awaits you!!!

That was what I figured, also this was pre-transition, correct?

You location is really good, I would love to be able to go after as many markets as you have close with the ease that awaits you!!!


It is post-transition - I compared current to post and nothing changed. one PBS station jumped but I hardly ever watch PBS so I didn't care about that. Plus the transition is only 2 months away.

The satellite is only about 6 ft AGL on the corner of the house...I believe my neighbor's house would block the DB4 if I put it there. I assume that the sat is angled up much more than the DB4 would be. I take it Directv never comes to get thier dishes? Your thoughts on mounting it here?

My location is pretty much in the center of a triangle of fairly large cities.

I need a rooftop antenna to receive VHF 8, 9, and 11 plus UHF 14 through 41. Receivers are older Hughes HR10-250 D* units with OTA feed that augments the D* signal.

All stations are pretty close directionally (only vary a few degrees) and are around 40 miles away.

Antenna is two feet off of a second story roof and can't be raised significantly without violating homeowners restrictions. I can point directly at the stations, but it is not a direct line of sight (adjacent rooftops 30 feet away are approximately two feet higher, so don't get perfect line of sight) but not horrendous obstructions either.

Currently use a Winegard square shooter, which works fine (but not amazing) for the UHF stations and miserably for the VHF stations.

Suggestions?

Thanks.

It is post-transition - I compared current to post and nothing changed. one PBS station jumped but I hardly ever watch PBS so I didn't care about that. Plus the transition is only 2 months away.
Ok, good, any changes that are coming will not be an issue...


The satellite is only about 6 ft AGL on the corner of the house...I believe my neighbor's house would block the DB4 if I put it there. I assume that the sat is angled up much more than the DB4 would be. I take it Directv never comes to get thier dishes? Your thoughts on mounting it here?

Usually, they want the boxes back, but leave the dishes, and the wire they have installed (which is usually quad shield RG6) You could cheat and use their wire to get outside and just run it up to the peak, so you would not have to snake wire through the walls....
That is a bad location for it, the biggest thing I worry about with atitic installs, is what is the roof made of, do the walls have an vapor barrier, and that kind of thing, it sucks working outside in the winter, but on the flip side, at my grandma's house, will one uhf antenna pointed at 60 degrees at 10miles (one set of towers, another station at 300degrees at 22miles, and a strong station to 180degrees at 6miles), they come in easy on the roof, whereas with indoor antenna, the station to the back of tower at 180 was breaking up, and the station at 22miles was not reliable.. A small non-high-gain antenna made the reception perfect... Don't take as I am trying to tell you what to do, just bare in mind, that a roof install is my strong recommendation... (outside, without a huge loss, you can get away with antennas pointed the wrong with LOS, or close in and very strong, so that is where I coming from....

My location is pretty much in the center of a triangle of fairly large cities.
Ya, it is great, I am little to the South of being between three DMAs, but still working to grab all of them. I just poured the footing for a 40ft tower, and I am aiming to grab UHF/VHF-HI at 78.2miles from the Twin Cities here in MN, also looking to grab the Southern WI stations at 56miles... Every foot higher, can make a huge difference on the amount of signal that makes it around hills and trees and what not!

I need a rooftop antenna to receive VHF 8, 9, and 11 plus UHF 14 through 41. Receivers are older Hughes HR10-250 D* units with OTA feed that augments the D* signal.

All stations are pretty close directionally (only vary a few degrees) and are around 40 miles away.

Antenna is two feet off of a second story roof and can't be raised significantly without violating homeowners restrictions. I can point directly at the stations, but it is not a direct line of sight (adjacent rooftops 30 feet away are approximately two feet higher, so don't get perfect line of sight) but not horrendous obstructions either.

Currently use a Winegard square shooter, which works fine (but not amazing) for the UHF stations and miserably for the VHF stations.

Suggestions?

Thanks.

My thought, without seeing your tvfool, is to go about with close advise to what I gave jbsmith_05 up a little higher...

Ok, my thought is go with one DB4 (I think with 2 aiming in different directions, you could end up with bad multipath) and a Winegard HDP 269.. (this amp is lower on gain, and I have read here on AVS, that it does not overload easily, but you could also try a CM 7777.
In your case, as long as their are no high power radio stations within a few miles, I would go with the Channel Master CM2016, and a CM7777, the DB4's VHF gain at 40miles would prolly not be reliable without LOS....

OK, now I think I have a system design that will work for my locals and then some. I guess my DX will be mostly tropo, but here in Florida I expect to get plenty of that. The system is modest, and the antenna polar pattern is a little wide by design. This is so I can park the antenna at 180 degrees and get all my regular locals to the south (which I now get with a small antenna in the attic). I chose the Jerrold/Delhi/Wade VU-933SR for one reason; It has a slightly wider polar pattern to cover three tower locations to my south and enough gain to get the job done. I will be at 30' above ground (on the east coast...pretty flat). The rotor will be a CM9521A.

The big choice to make was on the preamp. After looking at Winegard and Channel Master "all-in-one" options, and listening to some advice here, I think the CM7778 is the perfect choice for this installation. Overload is not going to help, so the CM7777 is a bit too much (see calculations below). I will be splitting the signal into four rooms. I calculate no more than 100' total runs of RG6QS which I ran before the house construction was completed. Here is a breakdown of gains and losses on each band:

DEVICE LOW HI UHF
-------------------------------
VU-933 +6 +10 +9
CM7778 +16 +16 +23
- NOISE -3 -3 -2
LOSSES -9 -10 -13
CABLE &
SPLIT

LINK BUDG +4 +3 +8 (This is what is left of the preamp gain after accounting for all of the cable and splitter losses.)

TOTAL W/
ANTENNA +10 +13 +17 (This is the total signal gain you get over a dipole at each of the four receiver locations.)

That is not bad for a modest system. The balance is perfect when considering how each band propagates (low freqs travel further than hi freqs). I can remove the 4-way splitter for times when I DX, but that recovers preamp gain and not antenna gain. There is no making up for a good receiver and antenna gain. I think this is a well balanced system for an average home in a suburban to rural situation. The antenna has modest gain and is a little forgiving in directional characteristics. The rotor will allow me to have some DX fun. I doubt there will be any overload related problems. This system should work well. What do yall think?

One more question. Is anyone doing digital on VHF Low Band. I LOVE low band! I hope it stays around. Knowing the FCC they would give it away to cordless telephones or something stupid like that.
Phil

I live about 30 miles SE from Nashville. Channel 5 in Nashville is going back to Channel 5 after the transition. I also read on a thread here on avs that there is a station in Southern AL, Northern FL that is on channel 2 and is going to go back to channel 2 after the transition.

Robert

SOFA.KING:
Preventing Preamp "Overload" really means maximizing the Spurious Free Dynamic Range (SFDR),
so you can receive the weakest signals possible without intermods wiping it out.
Start with www.tvfool.com and www.fmfool.com to see what you're really up against.
You might be surprised to find stations you weren't aware of...

Calculations for various Preamps were posted on 4Nov:
http://www.avsforum.com/avs-vb/showpost.php?p=15005797&postcount=8148

WRGB Albany NY, will go back to channel 6 after transition.

My thought, without seeing your tvfool, is to go about with close advise to what I gave jbsmith_05 up a little higher...


http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d55368ee36c

SOFA.KING:
Preventing Preamp "Overload" really means maximizing the Spurious Free Dynamic Range (SFDR),
so you can receive the weakest signals possible without intermods wiping it out.
Start with www.tvfool.com and www.fmfool.com to see what you're really up against.
You might be surprised to find stations you weren't aware of...

Calculations for various Preamps were posted on 4Nov:
http://www.avsforum.com/avs-vb/showpost.php?p=15005797&postcount=8148


Thanks...and I know what you are saying is true. I have checked those "fool" sites. Very nice resource! I'm good to go!

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d55368ee36c

Emm, not bad, I would go with an amp for sure, the antenna is the interesting one, I think the before mentioned Channel Master with a 7777 amp will prolly get the job done....

(Sorry for the simulcast, but wasn't getting much response in HDTV Technical)

This may be quasi-legal for channels 51 and below and will soon be DEFINITELY illegal for 52-69 come 2/17, but I'd like to add an A/B switch on my second set, with one side going to the second set, and the other to an antenna. Said antenna would then broadcast the ol-fashun analog signal from our Dish two-tuner receiver about 30 feet to another set on the back deck, which then of course would have the UHF remote to tune the 2nd Dish tuner.

How many milliwatts are present at the 2nd set RF output would be the big question. So, is there enough signal to at least use small directional UHF antennas at each end in case of an itty bitty 1 milliwatt signal? Or in the case of 10 or 20 mW signal...how would I attenuate signal to a point where I'd cease to be a neighborhood broadcaster? Also how resistant is the Dish RF modulator to VSWR mismatches?

I live about 30 miles SE from Nashville. Channel 5 in Nashville is going back to Channel 5 after the transition. I also read on a thread here on avs that there is a station in Southern AL, Northern FL that is on channel 2 and is going to go back to channel 2 after the transition.

Robert

That is good to hear. Thanks! :)

WRGB Albany NY, will go back to channel 6 after transition.

I used to watch that channel where I grew up (Clinton Corners). It was the strongest channel we received. Glad to hear it is staying.

Long live low band! :D

(Sorry for the simulcast, but wasn't getting much response in HDTV Technical)

This may be quasi-legal for channels 51 and below and will soon be DEFINITELY illegal for 52-69 come 2/17, but I'd like to add an A/B switch on my second set, with one side going to the second set, and the other to an antenna. Said antenna would then broadcast the ol-fashun analog signal from our Dish two-tuner receiver about 30 feet to another set on the back deck, which then of course would have the UHF remote to tune the 2nd Dish tuner.

How many milliwatts are present at the 2nd set RF output would be the big question. So, is there enough signal to at least use small directional UHF antennas at each end in case of an itty bitty 1 milliwatt signal? Or in the case of 10 or 20 mW signal...how would I attenuate signal to a point where I'd cease to be a neighborhood broadcaster? Also how resistant is the Dish RF modulator to VSWR mismatches?
Yes, it's ILLEGAL...and costly if you get caught.
The cable companies (and the FCC) patrol neighborhoods from time to time
to make sure cable signals aren't leaking to disrupt avionic (and other) communications.

A milliwatt of power would overload many TVs.... Typical receive signal levels
are microwatts....down to nanowatts....

You'll probably need an RF amp, which is ALSO going to amplify all of
the broadband NOISE coming out of the Dish UHF output, causing problems
for your neighbors trying to receive OTA channels....

=====================================
What you CAN do is to connect the Dish L/R/Video outputs to a wireless video extender:
http://www.google.com/products?q=wireless+video+extender&scoring=p

I also read on a thread here on avs that there is a station in Southern AL, Northern FL that is on channel 2 and is going to go back to channel 2 after the transition.

Which station are you thinking of here? The current plan has only 1 DTV station on the East Coast on 2 (WLBZ in Maine). If you are thinking of WTWC, it is returning to 40.

Which station are you thinking of here? The current plan has only 1 DTV station on the East Coast on 2 (WLBZ in Maine). If you are thinking of WTWC, it is returning to 40.


I was looking for that info too. It would be cool if they were going to channel 2 though. I noticed a trend of some stations leaving UHF and going to VHF for the first time. In this case "the grass IS greener". If I were looking for an open VHF channel for my station, I would pick channel 6. There are very few of them around the country and it would be a huge range boost.

Long live LOW BAND! :D

I was looking for that info too. It would be cool if they were going to channel 2 though. I noticed a trend of some stations leaving UHF and going to VHF for the first time. In this case "the grass IS greener". If I were looking for an open VHF channel for my station, I would pick channel 6. There are very few of them around the country and it would be a huge range boost.

Long live LOW BAND! :D

Wouldn't that just be asking for trouble for everyone with an FM filter?

There is a proposal at FCC to expand FM band into Ch6 and possibly also Ch5.....

Indoor antennas for Lo-VHF are very low gain....and outdoor antennas are HUGE!!!!

AND Ch6 is trouble for anyone located near an FM transmitter...they're everywhere, they're everywhere....

PS: You can check for FM adjacent channel interference to Ch6 at www.fmfool.com,
and/or download an FM transmitter location icon file (*.kmz for GoogleEarth display).

That's being discussed up here in Canada too. The idea would be to have a 30MHz FM band as opposed to today's 20MHz band. Speculation is that the new 10MHz portion at the low end would have a purely IBOC (Hybrid Digital) only set of frequencies. Its all just talk at this point, as far as I've heard.

Agreed about the antenna size! ;)

Indoor UHF antennas are also low gain. Who uses indoor antennas anyway? that never worked good and never will work good. OTA on an indoor antenna is half@$$ed at best.

More FM broadcast (now with "HD") in place of channel 5 & 6? Bad idea. Maybe channels 2, 3, and 4, but with the FCC selling off channels 52 - 69 and the land mobile intrusion on channels 14 - 20, not to mention channel 37 being off limits, what the hell is left? I mean COME ON! Does anyone at the FCC have a clue?

The last thing that needs to happen is doing away with more channels for TV. And low band tv antennas are not "huge". A 100" dipole for channel 2 (the longest) is nothing. Pfffft! :rolleyes:

Wouldn't that just be asking for trouble for everyone with an FM filter?

No...maybe more trouble for people without filters. So get a good filter. No big deal. Just do it.

Who uses indoor antennas anyway? that never worked good and never will work good. OTA on an indoor antenna is half@$$ed at best.

That's a rather snobish attitude don't you think. Many people who live in apartments or condos don't have much choice. Of course one could fight with the landlord or HOA for the right to install an outdoor antenna, but for most people, that's just too much trouble.

For the past 20 years or so, I paid for cable TV service because analog TV reception via an indoor antenna sucked due to severe ghosting. However, digital TV reception via an indoor antenna has been awesome for nearly a year now. Call it what you want, but at least I don't have to pay for cable anymore.

Hello,
I have read that many people have built thier own db4 antenna out of a 2x4, some copper wire, balun, and some oven racks.

couple questions:

1) has anyone built their own and then also purchased one? If so would like to know if there is any discernable differance in signal strenght and/or picture quality

2) I was thinking of building one first - since I have everything laying around the house already, but my question is what should the distance between the 'racks' and the rods (v's) be? I assume 4 in?

That's a rather snobish attitude don't you think. Many people who live in apartments or condos don't have much choice. Of course one could fight with the landlord or HOA for the right to install an outdoor antenna, but for most people, that's just too much trouble.

For the past 20 years or so, I paid for cable TV service because analog TV reception via an indoor antenna sucked due to severe ghosting. However, digital TV reception via an indoor antenna has been awesome for nearly a year now. Call it what you want, but at least I don't have to pay for cable anymore.

No, I don't "think".

I lived in appartments for 14 years and managed to get an antenna up for TV and ham radio in every case. Some landlords could be reasoned with, some not. In one case I had access to the crawl space and put antennas in the attic. In another I threw magnet wire out the window into the trees and grounded my feedline to the water pipes. That made a very good ham antenna (better than other outdoor antennas I had up in the clear). In other cases I made quad loops for tv and taped them to the window. I got good reception. I put dipoles in the trees next to my window. And many other experiments that worked. I have tried it all and had no problems in many different appartments. I have always managed to "make it work" and rabbit ears were not part of a good solution.

Where there is a will, there is a way. You just need to make a little effort. ;)

AND Ch6 is trouble for anyone located near an FM transmitter...they're everywhere, they're everywhere....

Heh, tell me about it. :p Plus VHF-Low is noisy, easily picking up all sorts of interference. I would have rather seen them leave us with channels 7 - 57, and set up DTS repeater transmitters all over the place.

2) I was thinking of building one first - since I have everything laying around the house already, but my question is what should the distance between the 'racks' and the rods (v's) be? I assume 4 in?
Yeah, 4 to 5 1/2 inches is the general range, with 4 1/2 inches being the sweet spot for most.

More FM broadcast (now with "HD") in place of channel 5 & 6? Bad idea. Maybe channels 2, 3, and 4, but with the FCC selling off channels 52 - 69 and the land mobile intrusion on channels 14 - 20, not to mention channel 37 being off limits, what the hell is left? I mean COME ON! Does anyone at the FCC have a clue?


Land Mobile intrusion on channels 14 - 20? Expanding the FM band? Is there a chart available anywhere that shows what frequencies are used for what? :confused:

AND Ch6 is trouble for anyone located near an FM transmitter...they're everywhere, they're everywhere....

Oh my.....is that a Chicken Man reference?!?

Braaak, Braa, Braaaaakkkkk

Land Mobile intrusion on channels 14 - 20? Expanding the FM band? Is there a chart available anywhere that shows what frequencies are used for what? :confused:
Here's the chart...keep zooming in to see 54-108, 172-216 and 470-700 MHz:
http://www.ntia.doc.gov/osmhome/allochrt.pdf
Note that TV bands are used for not only wireless microphones, but also
medical monitoring equipment (incl on "forbidden" Ch37), Land Mobile
(Police/Fire/Taxi) and possibly some old reporter-to-station links from mobile TV vans.

Perhaps an easier to read chart:
http://www.commandline.net/Radio%20Frequency%20Chart1.htm

BTW: These are SUMMARIES and are NOT all inclusive....
For example, in S.D., Qualcomm used Ch53 to test MediaFlo before moving to Ch55.

Indoor UHF antennas are also low gain. Who uses indoor antennas anyway? that never worked good and never will work good. OTA on an indoor antenna is half@$$ed at best.

All depends on how far away you are (most people live in cities with strong signals)
and what you can live with (you can't miss what you don't know about)....

Fol. study says about 75% of OTA viewers use indoor antennas:
http://www.tvtechnology.com/article/19986
Q: Presumably "indoors" includes attic????

BTW: My son's attic mounted "indoor" CM-4228 picks up all L.A. stations 70+ miles away.
Unfortunately, I'm behind a hill and only get 4 out of 7 stations, even with
"indoor" CM-4228....and no help outdoors either....

Braaak, Braa, Braaaaakkkkk

I think he means the old 1510 AM (?) WKBW in Buffalo, NY Chicken Man, heh.

All depends on how far away you are (most people live in cities with strong signals)
and what you can live with (you can't miss what you don't know about)....

Fol. study says about 75% of OTA viewers use indoor antennas:
http://www.tvtechnology.com/article/19986
Q: Presumably "indoors" includes attic????

BTW: My son's attic mounted "indoor" CM-4228 picks up all L.A. stations 70+ miles away.
Unfortunately, I'm behind a hill and only get 4 out of 7 stations, even with
"indoor" CM-4228....and no help outdoors either....

I do not consider attic mounted the same as indoor rabbit ears. Not only are the antennas usually bigger and better but, depending on construction, you are above walls and other obstructions. Take my house for example...I have concrete block outer walls, wires in the walls (and some people have metal framing...not me), and depending where the TV is positioned, a set of rabbit ears might not even face the right direction. My in attic antennas shoot through wood (not too impeding) and get pointed in the right direction. Range is greatly extended. I think this is a good solution for many in my area since all the stations are only up to 50 miles away. Low band channels would do better over those hills and mountains, and in-the-attic antennas would be ok for low band reception if you keep the antenna as far away from electrical wires as you can.

The point here is that set top antennas are the worst. People can't expect to get all the local channels on them (low band or not) unless they live next to all the local transmitters. Complaining about low band rabbit ears is silly. It may be a challenge to do something better, but it is what it is. If they are too lazy to learn and don't want to bother doing something better, they can get cable. And no matter what people expect out of indoor antennas, not everyone will live close enough to the transmitters for it to work. Even if you are close enough to a couple of stations, there are bound to be others just out of reach for such an effortless and lazy set top copout. If you want to do OTA, you had better get a better antenna than some "set top" junk. Low band works better in hilly country, period. So what if an attic or outdoor antenna is a little wider. Big deal! :rolleyes: The advantages far outweigh the disadvantages. Oh...and FM interference can be mitigated with a good FM filter (not Crapshack). It is no big deal.

Hello,
I have read that many people have built thier own db4 antenna out of a 2x4, some copper wire, balun, and some oven racks.

couple questions:

1) has anyone built their own and then also purchased one? If so would like to know if there is any discernable differance in signal strenght and/or picture quality

2) I was thinking of building one first - since I have everything laying around the house already, but my question is what should the distance between the 'racks' and the rods (v's) be? I assume 4 in?

If you really want to build your own antenna then I'd recommend you check this link out... Lumenlab's DIY Antenna Thread (http://www.lumenlab.com/forums/index.php?showtopic=9613&hl=8-bay+antenna) . There are good designs within it's 63 pages of messages along with lots of experimentation (some good some bad). It should make for a nice read.:D

Best wishes,
Ed

Actually if you really want to build your own antenna go for the best:

"What is the Gray-Hoverman Antenna?" (http://www.digitalhome.ca/forum/showthread.php?t=81982)

Two interesting articles by Doug Lung on the TV Technology web site, on the Gen 1 Gray-Hoverman antenna.

Doug's first article was based on the GH GPLv3 design information and he provided links to the digitalhome GPLv3 web site.
His second article shows some builds made by some of his readers and the build by Robert Lynch, assistant chief engineer at the Fox affiliate in Roanoke, Va., has a very interesting reflector-screen variation, that others might want to try.

Here are the links:

http://www.tvtechnology.com/article/68436

http://www.tvtechnology.com/article/68820

Take my house for example...I have concrete block outer walls, wires in the walls (and some people have metal framing...not me),
And lots of people have foil backed insulation in the walls, like me. It also seems some of the newer shingles have something like ground up steel wool in them. Anything but outdoors is a poor mounting location.

FM Notch Filters attenuate one station. So you might need more than one....
If nearby station is towards low end of FM band (e.g. at or near 88.1 MHz),
standard notch filter from Tin Lee (et. al.) will ALSO affect Ch6:
http://www.tinlee.com/PDF/VR7-instu-page-low-Hi-specs.pdf

Tin Lee makes higher performance Notch Filters....for a much higher price:
http://www.tinlee.com/FM_Products.php?active=2
http://www.tinlee.com/Graph_ALL_FM_filters.php

Note that entire FM Bandstop Filters attenuate Ch6 even more:
http://www.tinlee.com/PDF/CR7%20FM%2040.pdf

I think the major cylindrical filter manufacturers, like Eagle, C&E. Microwave Filter and Gamco, stock all the FM values (88.1, 88.3, etc) and I'd expect them to sell for under $20 each. Almost no one ever needs more than one or two, since most FM band reject filters cover 93-108 MHz.

The Winegard FT-7600 is a crappy tunable FM notch filter, and while it only costs about $20, it can't be tuned without a meter, and the notch is not real sharp, so even when precisely tuned, it will nibble into channel 6. The Blonder Tongue MWT-2 dual, tunable notch filter is nice but costs the better part of $200.

Fol. study says about 75% of OTA viewers use indoor antennas:
http://www.tvtechnology.com/article/19986
Q: Presumably "indoors" includes attic????

It states:

“75 percent or more of the over-the-air households have only set-top antennas.”

So perhaps, it does not even include attic antennas in the 75%.

I would not include my attic installation in the "half a'd," category. I have 3 antennas (Y5-2-6, YA-1713 and CM4228) for 51 miles w/o LOS, combined with an HLSJ for the VHF side and combined with UHF by way of a 7777. The Y5-2-6 is for "fun" only as I don't need it for DTV. I only need the 4228 at the moment and may not need the YA-1713 for 7-13 since the 4228 does well enough, but I wanted a robust installation.

It is certainly in better condition than 95% of the local outdoor installations I see. The way I look at it, unless an outdoor antenna and equipment is replaced (or at least tuned) on a regular basis, it loses much of its advantages over attic installations. Most local outdoor antennas are pointed the wrong way, which also gives back most of the advantages.

Of course, for houses with stucco or metal siding, it won't work nearly as well to have an indoor antenna, but that describes about 90% of new homes built in SoCal. In my case, stucco is only on the 1st floor and the attic UHF antenna looks through the wood siding of the house and not the roof tiles (which the VHF antennas look through).

Relying on set-top antennas will be a mistake made by many. There was was article in the Washington Post which showed someone wrapping foil around the antenna to try and improve the reception. Here is the article.

http://www.washingtonpost.com/wp-dyn/content/article/2008/05/19/AR2008051902730.html

Effective reception requires better antennas and better located/situated antennas. I think we can agree on those points.

FM Notch Filters attenuate one station. So you might need more than one....
If nearby station is towards low end of FM band (e.g. at or near 88.1 MHz),
standard notch filter from Tin Lee (et. al.) will ALSO affect Ch6:

It will be interesting to see what happens in my situation when channel 6 returns to real channel 6 digital in February. Im fortunate in that the nearby strong FM stations are in the 90 degree null of where I point the antenna to.

I'm planning to put up an antenna for my grandfather; see attached for post-transition TVFool data (assuming a 40-ft antenna mast). I want to be able to receive KBTX, plus everything from Houston (southeast direction) down to KHOU at least.

Currently (for analog) he uses an indoor antenna (the Radio Shack "UFO") which gets KBTX great and the Houston channels very weakly. With a converter box, KBTX is the only reliable signal, so obviously a better antenna is needed.

Since we only want to buy one antenna (preferably without needing a rotator), and we're 67 miles from the Houston antenna farm, I am looking at getting the Winegard HD7698P and pointing it towards the southeast. There won't be any low-VHF stations post-transition, but there are three high-VHF stations, so that seems like a good choice.

At 105 degrees apart from the Houston stations, KBTX is in a big null of that antenna, which is probably a good thing, since it's a much stronger signal than everything else. (You can get a decent picture on its analog ch.3 with absolutely nothing connected to the TV's RF jack, and crystal clear with just about any length of wire.) Hopefully it will still come in with the antenna pointed as such.

I'm not sure how strong a preamp to buy, as I want to get a lock on the Houston channels, without having KBTX overload the amp.

Hi guys, I'm brand new to the AVS Forums but I joined mainly due to this thread. I've had cable from about the age of 8 (30 now and a pricey digital cable package to go with it!), but fondly remember the old OTA days at my parents' house. I am getting into OTA myself after purchasing a 50" HDTV and wanting the best picture possible for the local channels. I also want to protect myself after the digital transition if I move to satellite (7 TVs and I'd want at most 4 satellite STBs, leaving three more TVs to cover).

Anyway, on to the meat of the post. I want to dabble in DXing later on if time/money permit, but for now I want to keep it simple. I've attached the TV Fool report for my exact coordinates post-transition while leaving the antenna height blank. Here's what I want:

1) Roof mounted antenna on my single story home.
2) The St. Louis stations located from 255-273 degrees.
3) I'd like to have WSIU Ch. 8.
4) I want to view these on my two main TVs for sure but also if possible on two more tvs. The longest cable run should be 75 feet at most, less for the two main tvs centered in the house on the main floor and the finished basement family room.

After studying this for about a week, I think some type of Channel Master UHF antenna should do the trick and hopefully allow me to pull in WSIU. I'll get WPXS no matter what I do. I know people say to get a little more antenna than I need. If I get a CM4228HD, would I also need/want a CM7777 pre-amp? Is a 4228HD overkill by itself? Not having had real world experience with OTA, I have no practical experience to guide me here. What do you think?

Which station are you thinking of here? The current plan has only 1 DTV station on the East Coast on 2 (WLBZ in Maine). If you are thinking of WTWC, it is returning to 40.

I think this is where I read this, but I notice now that this was posted back in 2005, so maybe it is now out of date. It was posted by "Trip in VA" in the "Low-VHF" Thread: (The Dothan AL PBS Station)


With just over 500 stations that will be making elections today, here's the list of low VHF elections so far:

Elected Channel 2:

KTNL-13/2 CBS/PAX Sitka, AK
WDIQ-2/11 PBS Dothan, AL
KNAZ-2/22 NBC Flagstaff, AZ
KREX-5/2 CBS Grand Junction, CO
WCES-20/2 PBS Wrens, GA
WLBZ-2/25 NBC Bangor, ME
WWMT-2/3 CBS Kalamazoo, MI
KNOP-2/22 NBC North Platte, NE
KVBC-3/2 NBC Las Vegas, NV
KOTA-3/2 ABC Rapid City, SD
KUSD-2/34 PBS Vermillion, SD
KBEJ-2 UPN Fredricksburg, TX
KJWY-2/14 NBC Jackson, WY

Elected Channel 3:

KIEM-3/16 NBC Eureka, CA
WDLP-22/3 IND Key West, FL
KYUS-3/13 NBC Miles City, MT
KBJN-3 NBC Ely, NV
KDLO-3/2 CBS Florence, SD
WBRA-15/3 PBS Roanoke, VA

Elected Channel 4:

KJNP-4/20 Rel. North Pole, AK
WHBF-4/58 CBS Rock Island, IL
WDKY-56/4 FOX Danville, KY
WSKY-4 Ind. Manteo, NC
WOAY-4/50 ABC Oak Hill, WV

Elected Channel 5:

KYES-5/6 UPN Anchorage, AK
WABW-14/5 PBS Pelham, GA
KGTF-12/5 PBS Agana, GU
WOI-5/59 ABC Des Moines, IA
WBKP-5/11 ABC Calumet, MI
WGVK-52/5 PBS Kalamazoo, MI
KXLF-4/5 CBS Butte, MT
KHAS-5/21 NBC Hastings, NE
WLMB-40/5 Rel. Toledo, OH
KOBI-5/15 NBC Medford, OR
WMC-5/52 NBC Memphis, TN
WTVF-5/56 CBS Nashville, TN
WCYB-5/28 NBC Bristol, TN
WDTV-5/6 CBS Weston, WV

Elected Channel 6:

KRMA-6/18 PBS Denver, CO
KBSD-6/5 CBS Ensign, KS
KTVM-6/33 NBC Butte, MT
WRGB-6/39 CBS Albany, NY
NEW-6 PBS Casper, WY

I'll update this list tomorrow.

- Trip
__________________
KJ4IEA

Come visit RabbitEars for digital TV info including Digital Transitional Reports!

"Ignorance and prejudice and fear walk hand in hand..." - Rush "Witch Hunt"

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Last edited by Trip in VA; 02-11-05 at 06:21 AM..

I would never consider putting an antenna on the roof, or in the attic, without a rotor. If multipath is an issue, one setting will not necessarily work all of the time. I aimed my latest indoor antenna during a period of calm winds that don't happen that often here in July. I wrote down the antenna positions for the locals from the same antenna farm. I figured I had to have the directions right. Yet, during the World Series, I saw a dropout on Fox with mild winds from the north, around 5mph. I proceeded to change the antennas position around 30-40 degrees, and reception was back to the 90% I'd seen in July. The difference in the locations of these local stations antennas is less than 5%. Good Luck.