FWIW, while the 15-1108 is a lousy pre-amp, the indoor section (without the mast-mounted module) makes a decent (enough) booster for use as a distribution amp.In that application, you should make sure the voltage is blocked so it doesn't short and suck down the power supply.

This is the only part that I've ever seen. I'll check the antenna side for voltage.

Thank you for your inquiry!

There is no way to save all channels when you are repositioning the
antenna.

Thank you for your interest in Panasonic products.

Thank You,
Panasonic Consumer Support

Above is the reply to my question about why the Panasonic TCP50X1 Plasma TV will not save previous channel scans. I can receive stations from 4 different directions with a rotor, but this tv is useless to me. But the cheap Digital Stream DTV Converter Box for my older tv saves previous scans! Is there a way to save scans with the Panasonic TCP50X1? Is there a list of TVs that save previous scans?

I can receive stations from 4 different directions with a rotor, but this tv is useless to me. But the cheap Digital Stream DTV Converter Box for my older tv saves previous scans! Is there a way to save scans with the Panasonic TCP50X1? Is there a list of TVs that save previous scans?

What does your Panasonic TCP50X1 do if you enter the actual RF channel number (not the PSIP channel) of a new channel (one that it hasn't already scanned)? This will cause many TVs to add the channel to the channel list. If yours does that, then you could scan in the direction with the most channels, then aim the antenna in other directions and manually add the channels found there. It's tedious, but it will work with some TVs.

What does your Panasonic TCP50X1 do if you enter the actual RF channel number (not the PSIP channel) of a new channel (one that it hasn't already scanned)? This will cause many TVs to add the channel to the channel list. If yours does that, then you could scan in the direction with the most channels, then aim the antenna in other directions and manually add the channels found there. It's tedious, but it will work with some TVs.

This also works for me with my Samsung 52" LCD (not sure the model number). However, if the RF channel number of the desired station is the same as the PSIP number of another station, the second station will be selected and I have found no way to get the first station.

Mike

This also works for me with my Samsung 52" LCD (not sure the model number). However, if the RF channel number of the desired station is the same as the PSIP number of another station, the second station will be selected and I have found no way to get the first station.

Mike

just a guess, don't have that set.

delete the virtual channel number. enter the other channel with its real channel number. enter the real channel number of the one you deleted. only enter real channel numbers and do the real entries before that number becomes a virtual entry.

I've noticed DTV's don't seem to have the features of CECB's (ie. EPG (at least a NOW/NEXT), additional channel scan, Program description, etc.). This seems crazy to me, considering how much they are charging for flat panels.

Yep. Vizio however has the goods that the "Expensive Brand Names" should.....like EPG guide and information.

I've noticed DTV's don't seem to have the features of CECB's (ie. EPG (at least a NOW/NEXT), additional channel scan, Program description, etc.). This seems crazy to me, considering how much they are charging for flat panels.

A lot of those features were mandated for the CB to be eligible for the NTIA coupon program.

A lot of those features were mandated for the CB to be eligible for the NTIA coupon program.
Not really. The NTIA says that the boxes have to meet the usual standards, but cannot have "bells and whistles" that would keep them from qualifying for the coupon.

As far as I can tell, the requirements that allow program guide info (PSIP) are no different than the requirements for any other DTV tuner. Whether (and how) the maker decides to show this info is up to them. My TV shows the channel (duh...), what's on, and the parental rating.

The NTIA says that the boxes have to meet the usual standards, but cannot have "bells and whistles" that would keep them from qualifying for the coupon.

ELIGIBLE CONVERTER BOXES SHALL COMPLY WITH THE FOLLOWING MINIMUM PERFORMANCE SPECIFICATIONS AND FEATURES:

3. PSIP Processing
Equipment shall process and display ATSC A/65C Program and System Information Protocol (PSIP) data to provide the user with tuned
channel and program information. See ATSC A/69 for further guidance.

HDTVs do not have to comply with this requirement.

Not really. The NTIA says that the boxes have to meet the usual standards, but cannot have "bells and whistles" that would keep them from qualifying for the coupon.

As far as I can tell, the requirements that allow program guide info (PSIP) are no different than the requirements for any other DTV tuner. Whether (and how) the maker decides to show this info is up to them. My TV shows the channel (duh...), what's on, and the parental rating.

It helps if you refer to the list of required, permitted, and disqualifying features before commenting...

See http://www.ntia.doc.gov/dtvcoupon/dtvmanufacturers.pdf for a simplified version.

Formal specifications were issued as part of the Final Ruling and are available here: http://www.ntia.doc.gov/frnotices/2007/DTVCouponFinalRule_031207.pdf

It helps if you refer to the list of required, permitted, and disqualifying features before commenting...

See http://www.ntia.doc.gov/dtvcoupon/dtvmanufacturers.pdf for a simplified version.

Formal specifications were issued as part of the Final Ruling and are available here: http://www.ntia.doc.gov/frnotices/2007/DTVCouponFinalRule_031207.pdf
Well, excuuuuuuse me! It also helps if you don't assume what I did or didn't refer to before I commented.

Simplified versions do not necessarily have the force of law. The simplified version was quoted earlier, and it agrees with the actual rules and regulations. However, while it may appear clear, the rules do NOT specify, precisely, which PSIP parameters must be displayed. Manufacturers are free to decide for themselves what information their customers will want, subject to clear FCC regulations, just as the situation is for "regular" TVs.

The NTIA requires that converters boxes "receive, decode and display information contained in the PSIP broadcast pursuant to the A/65 standard." But which information? A/65 defines what must be put into the PSIP tables that are transmitted (and there are a LOT of them!) but it does not say which ones should be displayed.

From the Rules and Regulations, "Further, NTIA will permit, but not require, a CECB to display other electronic program information." Which are required and which are permitted? Tuned channel is specifically mentioned and makes sense, parental control information is required by the FCC, but how much of the program information should be displayed. Current? Current and next? Channel name? The rules don't really say which.

PSIP decoding and processing is required in all TVs, not just CECBs. I do not believe that it is accurate to say that the features mentioned in the post that started this particular discussion were "mandated" by the NTIA in order to be "coupon eligible."

Two of my local stations went to VHF for DTV. So, I needed to install a VHF antenna. I took down my mast to add an AntennaCraft Y10-7-13 stacked below my existing ChannelMaster UHF yagi. I decided to check out the rotator before putting everything back up. The rotator didn't turn. I don't know how long it has been like this. The transmitters for all the stations I have been watching are within a mile and a degree or so each other. When I installed the original UHF antenna I adjusted for peak performance and left it. That was years ago when the first local stations started broadcasting DTV in addition to analog.

I removed the works from the housing. There was no obvious problem. All the gears were intact, the motor buzzed when energized, but it didn't move. I removed the motor and found that it was the culprit. The rotor would not turn by hand. I applied a judicious amount or torque to the tiny gear on the end of the rotor with a pair of pliers and it started to moved. After moving it back and forth several times, it was moving freely. It appears that if the motor is not used for a while, the rotor can seize up. This is not entirely unexpected with moving devices.

Moral here is to use it regularly if you want it to keep working. And if it does seize up, it may be fixable.

Moral here is to use it regularly if you want it to keep working. And if it does seize up, it may be fixable.
Good advice, and not just for antennas! :)

Moral here is to use it regularly if you want it to keep working. And if it does seize up, it may be fixable.

The problem is that grease dries out over time. The more volatile hydrocarbons evaporate leaving just thick gunk. The long term solution is to clean the old grease with a solvent and replace it with a grease or oil that does not decompose. Silicone grease is one such compound. There may be others.

I have a situation where I am pretty sure I am getting an overload conditon from 2 ufh stations and 1 vhf. I guess that leaves me with 2 questions the first being can I get a filter, attentuator for vhf channel 12 only and I see there is a winegard 2700 dual tuneable attentuator for uhf. Is all this to many hook-ups etc and If this is the route taken will these types of filters etc cause a signal degrade in the adjoining channels which leaves me to the same situation I have now.

tunamike:
What does your exact address tvfool.com report look like and what channels are you concerned about?

tunamike,

I doubt WWPX is causing an "Overload" condition. As for WHAG and WWPB, you're at least 15 miles from those transmitters.

Since we get stations on 7, 8, 9, 10 (Harrisburg), 11, 12, & 13 here in Franklin County, using a channel trap is nearly impossible (unless you're willing to give up adjacent channels).

My best solution so far (I'm still working on other options) is to use two antennas (one on a rotor) and an A/B switch and/or RF/RCA options with multiple CECB's (each room has three).

The fixed antenna is peaked for W08EE-D (WNPB - WV PBS 24), which also gives me WHAG, WWPB, WVPY, WWPX, and WJAL.

My rotor antenna is mostly set for WMAR, WJZ*, WUTB, WBFF*, and WNUV. It's set for WTAJ (Mon. through Fri.) to record Y&R and tuned to WPMT when FOX is required. I'm working on getting WLYH with a fixed yagi (WTAJ and WPMT are going that way soon).

Speaking of WLYH, have you tried setting your antenna almost due North (350° to 5°M) to catch them? If not, give it a try. Even though it is 90° off-axis, both Dewster1977 and I have found that is where we receive the station. We believe it's bouncing off the Tuscarora Ridge somewhere.

Finally, I'll be looking to improve reception of WTTG, WJLA, WUSA, and WDCA. Like WJZ and WBFF, I can't get any dependable reception for those stations.

Also, give WDCW a call and ask them to at least reactivate W51CY as analog, until they get the finances to convert to digital. WITF's W38AN could be coming on-line at the end of the month (can't wait for PA PBS).

tunamike:
What does your exact address tvfool.com report look like and what channels are you concerned about?
tvfool prefix for my chart its still a little crazy some I should not get but I do real well and some that I should be getting can only get limited



?option=com_wrapper&Itemid=29&q=id%3d23c523c9d46b7b

I have a situation where I am pretty sure I am getting an overload conditon from 2 ufh stations and 1 vhf. I guess that leaves me with 2 questions the first being can I get a filter, attentuator for vhf channel 12 only and I see there is a winegard 2700 dual tuneable attentuator for uhf. Is all this to many hook-ups etc and If this is the route taken will these types of filters etc cause a signal degrade in the adjoining channels which leaves me to the same situation I have now.

You can buy a single channel notch filter for channel 12 from http://www.eaglecomtronics.com/

You can buy a single channel notch filter for channel 12 from http://www.eaglecomtronics.com/

I don't think a notch at the NTSC video carrier location will do much good in attenuating a digital signal. It'll probably still make it unusable, but it won't stop most intermodulation it's involved in it.

I don't think a notch at the NTSC video carrier location will do much good in attenuating a digital signal. It'll probably still make it unusable, but it won't stop most intermodulation it's involved in it.

I was suggesting an RF notch filter designed to attenuate the frequencies from 204 MHz to 210 MHz ( channel 12). I believe what you described above is know as , among other things, a negative trap. Another good source for custom notch filters is http://www.tinlee.com/index.php

I don't think tunamike is looking to eliminate 12 as much as reducing the level down to what 11 and 13 are.

I was suggesting an RF notch filter designed to attenuate the frequencies from 204 MHz to 210 MHz ( channel 12). I believe what you described above is know as , among other things, a negative trap. Another good source for custom notch filters is http://www.tinlee.com/index.php

It's a terminology issue. If you just want to make a signal hard to use, you can use a filter which is very deep and very narrow -- that's a notch. If you want to prevent overload from a digital signal (which is roughly flat across its bandwidth), you need a filter which is as wide as the channel-- that's a bandstop filter.

Tinlee does have adjacent channel bandstop filters; I have no idea what they cost but I'll bet they aren't cheap.

I didn't see any specs/curves on the Eagle website.
Soon-Tai has lots of specs/curves, here is a typical single channel TRAP:
http://www.soontai.com/TRF.html
Note that the 10 dB suppression bandwidth is only 1.5 MHz, well short
of the full 5.8 MHz signal.

Tin-Lee's CE-7 Single Channel Elimination and CR-7-FM Bandstop Filter
curves show how adjacent channels are significantly affected:
http://www.tinlee.com/Graph_CE7_Spec_Order.php?active=1
http://www.tinlee.com/Graph_ALL_FM_filters.php

NO, you can't attenuate one channel without affecting adjacent
channels....not only by attenuating them, but also by injecting
ENVELOPE GROUP DELAY well into the adjacent channels, which
will totally mess up the Adaptive Equalizer in the DTV Receiver.....
Tin-Lee doesn't provide DELAY specs for the above, but they do for fol:
http://www.tinlee.com/CATV_MATV-LowpassCustom.php

==================================
About the only way to attenuate an adjacent channel is using two antennas
with phasing lines adjusted to point a null towards the undesired channel:
http://www.avsforum.com/avs-vb/showthread.php?p=14593948

NO, you can't attenuate one channel without affecting adjacent
channels....not only by attenuating them, but also by injecting
ENVELOPE GROUP DELAY well into the adjacent channels, which
will totally mess up the Adaptive Equalizer in the DTV Receiver.....

From what I can find, the adaptive equalizer in a DTV tuner can handle delay spreads greater than the ~100ns caused by those filters. They can probably handle some attenuation in the adjacent channels as long as it is consistent.

From what I can find, the adaptive equalizer in a DTV tuner can handle delay spreads greater than the ~100ns caused by those filters.

The word delay is used in two distinct contexts;

Delay compensation to eliminate multipath is slightly less than 100 ms in most tuner chips.

Group delay is a change of the time delay between two frequencies. Let's say that it takes x time for the bottom frequency of the channel to arrive at the tuner, but the top of the channel arrives X+1 or X-1 which may be sooner or later.

From what I can find, the adaptive equalizer in a DTV tuner can handle delay spreads greater than the ~100ns caused by those filters. They can probably handle some attenuation in the adjacent channels as long as it is consistent.
The problem is that channel 12 is LOS at 53.7 NM and 235° (M), while 11 and 13 are 2-edge at -18.9 NM and 121° (M).

From what I can find, the adaptive equalizer in a DTV tuner can handle delay spreads greater than the ~100ns caused by those filters. They can probably handle some attenuation in the adjacent channels as long as it is consistent.
In order to significantly reduce energy on adjacent channels, ATSC Transmitters
are required to have an Emissions Filter with very sharp skirts:
http://www.atsc.org/standards/a_64a.pdf

Early on, Gary Sgrignoli (et. al. at Zenith) analyzed the effect of the "mild"
5th Order Chebyshev Filter, finding it degraded the 8VSB signal:
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1190034

Example Ch44 filter had 80 ns difference in Group Delay between center
and +/- 3 MHz. Beyond 6 MHz band, filter reached a peak difference of 130 ns.

In other reports, Group Delay just outside the filtered channel was several
hundred nsec due to the use of higher order Chebyshev and Elliptic Filters....
which significantly affects ADJACENT channels.

To compensate for this degradation, transmitters use pre-equalizers,
which are designed to cancel out Freq Response & Group Delay problems
in the Emission Filter, sometimes with on-air feedback mechanisms to
constantly ensure the best transmitted signal as the system changes:
http://www.axcera.com/downloads/technotes-whitepapers/technote_8.pdf

The problem with single channel bandstop filters is the lack of any
GROUP DELAY SPECS. The devices would employ many poles in the internal
filter (like the 5-poles in the example Emissions Filter), which can
be expected to significantly affect adjacent channel (although
probably not next adjacent channels).

As was mentioned earlier, although they are somewhat related,
don't confuse Adaptive Equalizer performance with two wideband signals
delayed from each other (typical ATSC A/74 delay spec) with what the
underlying transmitter/receiver system must provide wrt flat frequency
response, low amplitude distortion and low group delay in the presence
of just one undistorted signal. We don't want to squander significant
portions of the Adaptive Equalizer's capability against transmit or receive
hardware deficiencies, leaving fewer degrees of freedom to attack
multipath signals.

PS: Same argument holds for minimizing VSWR, esp on long cables with
no Preamp where the reflections look like small-delay multipath, which
increases the Error Vector Magnitude (EVM)....(mis)treated here as if it
were degrading the Noise Figure (it has NOTHING to do with NF):
http://www.tvantenna.tv/papers/PFactorsV.pdf
http://www.tvantenna.tv/papers/dtv%20coverage%20and%20service%20prediction.pdf

Delay compensation to eliminate multipath is indeed rated at 100 ns in most tuner chips.
Multipath tolerance is expressed in microseconds. 100 nanoseconds would only be 100 feet of path length difference. Here's a product sheet that specifies the range of it's demodulator.

http://www.zoran.com/IMG/pdf/Cascade2.pdf

-34 to +78 microseconds. +78 is the largest figure I've seen for any chip.

Ron

Multipath tolerance is expressed in microseconds. 100 nanoseconds would only be 100 feet of path length difference.

Thanks for catching my mistake.

FWIW, I used tunable notch filters (From Blonder-Tongue and Winegard -) for a number of years to attenuate(before amplification) strong NTSC video or audio carriers a bit on 1st adjacent channels without difficultly regarding reliably decoding 1st adjacent channel DTV signals ...

Of the published specs I have available for what I used(I don't have the B-T specs handy, or a UHF winegard filter), the Winegard TRT-LO or Winegard TRT-HI filters I used were : for TRT-LO, tunable from 54~108 MHZ, TRT-HI tuneable from 174~213MHZ, with a Maximum 12dB notch, specs said the filters had a 2MHZ bandwidth at 1/2 power points (3dB) ... Obviously, I couldn't use those to knock down NTSC audio carriers without attenuating the lower portion of any "N+1" channel .... anyway, I don't believe they've made those things in quite a while ....

In fact actually still use one of the TRT-LO's tuned for maximum effect at about 88.7MHZ , and have decoded several Low-VHF stations on 6 via Es while using it .... (Have several strong FM stations in area on 88~89 MHZ) ....

I'm thinking about getting a preamp, I have VERY strong signals on my Tivax but my Sammy 151 could be better, it's very good but I want it as strong as possible. I heard I can overload the signal. What does this mean and what does it look like. Can you overload a digital signal?

I'm thinking about getting a preamp, I have VERY strong signals on my Tivax but my Sammy 151 could be better, it's very good but I want it as strong as possible. I heard I can overload the signal. What does this mean and what does it look like. Can you overload a digital signal?

Yes, you can overload the turner. It usually will act much the same as if it had a weak signal but the actual display may vary according to the receiver.

Unless you are getting breakups, freezes, or dropouts, then don't screw with it. The signal only has to be "strong enough". There is no benefit in having more than is needed for stable operation.

Thanks, what about a regular amp does that screw with the system or is that easy for the tuner to handle?

Thanks, what about a regular amp does that screw with the system or is that easy for the tuner to handle?

Try to understand this:

Do NOT use an amplifier unless it is needed. Period.

To avoid amplifier "overload" (actually desensitization due to Intermod Noise),
you want to maximize the SFDR (Spurious Free Dynamic Range) wherein
the Intermod Noise is no higher than the Thermal Noise:
http://www.arl.army.mil/arlreports/2007/ARL-TR-4235.pdf
http://www.odyseus.nildram.co.uk/Systems_And_Devices_Files/Linearity.pdf

IMD and SFDR Calculations for several common Preamps can be found here:
http://imageevent.com/holl_ands/files/ota

High Gain Preamps are suitable in RURAL locations....but check www.fmfool.com for nearby FM
transmitters and check www.tvfool.com to see if there is a Low Power TV nearby.
Low Gain Preamps are NOT suitable unless you are perhaps 10 miles away from towers (or indoors).
And if you are within a few miles of a transmitter, consider inserting a small amount
of attenuation (e.g. first try the 4 dB loss in a typical RF Splitter).

Since Intermods primarily occur on specific channels (3rd order is spread 3 channels wide),
some people can push these general guidelines a wee bit more....checkout the IMD Calculator....

Let me tell you all my setup and maybe the extra info can help. I'm about 25 KM from all the towers in Detroit.

CM4221 plus HBU33 on the roof each connected with about 3 feet rg6 into a splitter/combiner (radio shack).

Then into at least 60 feet rg59, split into a three way common splitter in the house.

One sent to a tivax about with about 15 feet rg6 and other with 25 feet rg6 to a sammy 151.

The third tv will soon be connected via 40 feet of rg6 also with a wall plate connection. The sammy is the issue it's older and hard to get a lock on some channels.

I'll check out those links in teh mean time thanks. EDIT links don't work for me.

CM4221 plus HBU33 on the roof each connected with about 3 feet rg6 into a splitter/combiner (radio shack).

Which directions are the two antennas aimed?

Let me tell you all my setup and maybe the extra info can help. I'm about 25 KM from all the towers in Detroit.
CM4221 plus HBU33 on the roof each connected with about 3 feet rg6 into a splitter/combiner (radio shack).
Then into at least 60 feet rg59, split into a three way common splitter in the house.
One sent to a tivax about with about 15 feet rg6 and other with 25 feet rg6 to a sammy 151.
The third tv will soon be connected via 40 feet of rg6 also with a wall plate connection. The sammy is the issue it's older and hard to get a lock on some channels.
With the three way splitter and that much cable (especially the RG59) something like the Winegard HDP269 pre-amp with 12dB gain might be a good match.

Tower Guy,

Both are pointed in the same direction.

Sammer,

Thanks I'll look into that preamp.

QUANTUM-FX ANT-101(ANT101) UHF/VHF Indoor TV Amplified ANTENNA or Winegard SS-3000 Amplified Indoor UHF/VHF Antenna

I'm about 13 miles form NY city on Long Island and the Monoprice antenna can't get 7, and now 11 and starting to drop 13 for some reason. Been looking for a new indoor antenna that will not cost much so thinking of one of these.

That 101 is a cheep indoor antenna ($14), the Winegard 3000 is a well made bidirectional indoor unit that goes for about $40. No comparison.

However, I don't know if either will solve your problem, without seeing a chart on you location. Give me your ZipCode, or attach a TVFool Chart for your Stations and we'll go from there.

QUANTUM-FX ANT-101(ANT101) UHF/VHF Indoor TV Amplified ANTENNA or Winegard SS-3000 Amplified Indoor UHF/VHF Antenna

I'm about 13 miles form NY city on Long Island and the Monoprice antenna can't get 7, and now 11 and starting to drop 13 for some reason. Been looking for a new indoor antenna that will not cost much so thinking of one of these.

High-VHF and an indoor antenna is often a recipe for frustration.

High-VHF doesn't penetrate structures as well as UHF does.

Try a simple VHF rabbit ears from Radio Shack for $10 to see if you can find a decent spot for the signal. Try different locations inside to see if you can find a "hot" spot.

High-VHF and an indoor antenna is often a recipe for frustration.

High-VHF doesn't penetrate structures as well as UHF does.



Actually the opposite is true. Higher frequencies penetrate less.

I'm new to the forum, so forgive me if I'm covering something simple. I've searched through the forum, but didn't find quite my particular situation.

I have a very specific objective, to improve reception of Channel 2 (digital channel 25) from Pittsburgh. I'm located about 65 miles NW of the KDKA antenna.

I am fortunate to have a third story roof onto which I've mounted a 12' mast, getting me pretty high with no nearby obstructions. I mounted a DB8 UHF antenna connected to a CM7777 Pre-Amplifier. The output is split to the TV and to a Satellite DVR that integrates OTA signals. (I've have removed the split with little impact on reception).

The result has been pretty good. The satellite receiver indicates signal strength with a rating of 0 to 100. With this setup, channel 2 registers in the 60s, but the signal strength varies significantly. It will bounce around between 55 and 70 with some pixelation, but occasionally, it will just drop to 0.

My questions:
Is this normal behavior for a distant source? Does 0 just mean that the signal has dropped below some minimum for the tuner and so it reads 0, or is the signal actually going away completely?

Secondly, any suggestions for further improving reception strength or stability? I've read in these forums the difficulty of combining antennas pointed in different directions, but what about for pointing them in the same direction? I have room on the mast to add another antenna if that would help. If so what are your suggestions for antennas and setup?

Thanks, Dan

I'm new to the forum, so forgive me if I'm covering something simple. I've searched through the forum, but didn't find quite my particular situation.

I have a very specific objective, to improve reception of Channel 2 (digital channel 25) from Pittsburgh. I'm located about 65 miles NW of the KDKA antenna.


Start at tvfool.com. It will show you what signal strength to expect. Here's the report for Warren, OH.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3dbefbff101160bc

If Warren is close to your actual location, your 7777 preamp is overloaded.

This is what is involved with stacking identical UHF antennas:

http://www.hdtvprimer.com/ANTENNAS/16bay.html

Actually the opposite is true. Higher frequencies penetrate less.

As proved by Buckaroo Banzai at the Banzai institute and latter stolen by John Smallberries at yoyodyne.
P.S. You will never get the Oscillation Overthruster

Actually the opposite is true. Higher frequencies penetrate less.

Actually you're wrong.

For whatever reason, hi vhf digital doesn't seem to do as well as uhf does and this seems to especially impact indoor reception. This was somewhat of a surprise and many stations are either scrambling to move back to uhf or increase power. It may have been an underestimation of the power levels necessary to match the prior contours and this has been discussed a fair amount already elsewhere here at AVS.

Actually the opposite is true. Higher frequencies penetrate less.

I would have been more accurate to state that, as a practical matter for the consumer, high-VHF DTV transmissions, at their substantially lower power levels, penetrates structures more poorly than do the higher powered UHF transmissions. This is due to the - guess what - difference in power levels.

I oversimplified for brevity.

UHF antennas: Several manufacturers offer both yagi and 8-bay reflector outdoor antennas (e.g. CM 4228 and 4248). What are the benefits and disadvantages of each?

For whatever reason, hi vhf digital doesn't seem to do as well as UHF does and this seems to especially impact indoor reception. This was somewhat of a surprise and many stations are either scrambling to move back to UHF or increase power. It may have been an underestimation of the power levels necessary to match the prior contours and this has been discussed a fair amount already elsewhere here at AVS.

Oh so this is why all the HI VHF 7,11,13 have been lost. Stupid people should have just left well enough alone, if it isn't broken don't fit it. There must be another part at play because i did get 7,11,13 after i moved my antenna but as the summer went on all were lost one at a time. Well i decided had enough playing with the monoprice antenna so ordered the winegurd 3000 hoping it will bring back 7,11,13.

Actually you're wrong.

To some the laws of physics are merely a suggestion. :) :) :)

As proved by Buckaroo Banzai at the Banzai institute and latter stolen by John Smallberries at yoyodyne.
P.S. You will never get the Oscillation Overthruster


Don't need it. The Flux Capacitor has proven far more effective at inter-dimensional travel!

PS I am, in fact, currently posting from 8th dimension.

I would have been more accurate to state that, as a practical matter for the consumer, high-VHF DTV transmissions, at their substantially lower power levels, penetrates structures more poorly than do the higher powered UHF transmissions. This is due to the - guess what - difference in power levels.

I oversimplified for brevity.

Technically higher frequency has less penetrating ability all else equal. Power levels are a different matter. If I'm not mistaken the reason FCC allocated higher power to lower frequencies is because of their superior range ability. AFAIK power levels are regulated to minimize interference.

Radio Control hobbyists who have experience with 2.4ghz vs 72mhz at similar power levels quickly learn the truth about penetration.

MTVhike,
Your request for comparison may be a moot point, I don't think that the CM-4248 is being made any more.

But to pursue some comparison...
Do you actually need a full range (Ch 2-69) or would HiVhf/UHF do ?
Would a Yagi Type or Bow Tie be better for your Mount/Location ? (depending on the answer of question 1)
Can you/your location handle a narrow (15°) Beamwidth, or did you plan to use a Rotator ?

These and probably many other questions about the requirements for your specific location (which should be the focus your search) can be answered if you go to...
TVFool Transmitter Locater (http://www.tvfool.com/?option=com_wrapper&Itemid=29)
and get the information about your location. Having done that, there's probably not going to be much "comparison" required. There's an Antenna that should clearly stand out, as being the right one for you.

OK got my new Winegurd 3000 antenna and gave it a try. First thing i noticed is CBS,FOX single strengths have dropped a lot but the stations are watchable. I have the Wineguard on a table behind a fan right now while the Monoprice was near the top of my wall so I'm not to concerned about that. Got ABC back right away and as i held the antenna higher also got back 11 but lost it again when i put it back down. Figured i would move it around the wall, find the right spot and buy a floating shelf so it can rest on. Sad it can't be hooked to the wall but the shelf will look nice. What is that big plastic thing hooked to the antennas back, clear plastic with tap around it. How does that help, yes i know it's a bow design but don't see how it helped since the single should pass right through the clear plastic part.

dagger,

Here's a spec sheet on the...
Winegard SS-3000 Spec. Sheet (http://manuals.solidsignal.com/SharpShooter_12-08.pdf)

It may help you understand it's capabilities. I generally don't like to even comment on an Indoor Antenna, just TOO many variables in the construction of the building and other factors. It would have been nice at least, to have seen a Chart on your location, the 3000 may not be the right antenna for you anyway.

Technically higher frequency has less penetrating ability all else equal. Power levels are a different matter. If I'm not mistaken the reason FCC allocated higher power to lower frequencies is because of their superior range ability. AFAIK power levels are regulated to minimize interference.

Radio Control hobbyists who have experience with 2.4ghz vs 72mhz at similar power levels quickly learn the truth about penetration.
Lower TV channels need LESS power (10's vice 100's of kilowatts for UHF)
because the PATH LOSS IS LESS. It's a function of both distance and frequency:
http://en.wikipedia.org/wiki/Free-space_path_loss

Problems with VHF fall into two basic categories:

1) FCC underestimated the man-made noise levels, which affects both outdoor and
especially indoor reception due to the proximity of fluorescent lights, dimmers, motors,
microwave ovens, leaky computers and other A-V Gear. And completely ignore lightning storms....

2) FCC insisted on maintaining the fiction that people are supposed to be using a 6 dBd
(8 dBi) OUTDOOR Hi-VHF antenna at a 30-ft height (with less than 2 dB downlead loss).
Consequently Indoor Antenna users fall 4-6 dB short on Gain and fall much further
behind when VSWR loss (incl. EVM degradation) is calculated:
http://www.tvantenna.tv/papers/PFactorsV.pdf
http://www.tvantenna.tv/papers/dtv%20coverage%20and%20service%20prediction.pdf
A UHF Loop is inherently a much better "antenna" than difficult to tune VHF Rabbit Ears.....
As you can see from these papers, there are also OTHER factors that have been underestimated.

I've been collecting Indoor Penetration Loss data for quite some time, but there
is almost NOTHING wrt VHF penetration in modern homes. I have seen one study
cited (unidentified....), claiming that VHF has difficulties penetrating into
modern homes due to the use of chicken wire in stucco and aluminized foil "wraps",
allowing BETTER penetration of UHF freqs via window openings.

HOWEVER, I have also seen specs wherein modern "Low-E" glass attenuates UHF
by about 20 dB (but no data wrt VHF!!!!). So enjoy what's left of the summer.....

So I'm just going to surmise that YMMV......A LOT!!!!!

Start at tvfool.com. It will show you what signal strength to expect. Here's the report for Warren, OH. [link removed because I'm a newbie.]
If Warren is close to your actual location, your 7777 preamp is overloaded.
This is what is involved with stacking identical UHF antennas: [link removed]


I'm SW of Warren (Lake Milton) and TVFool shows my kdka reception at -95db compared to the -85db on the scan you show.

From reading other posts, preamp overload would call for pointing the antenna slightly away from direct. Do you think that's still the case given the updated signal strength from TVFool? I wonder especially as my signal strength seems to be stronger at night and in that case the signal is also much more stable. Is that a counter-indication of overload? I tried simply unplugging the power to the pre-amp, but have read elsewhere that that's not the same as taking the pre-amp out of the pathway.

Thanks for the link to the 16 bay. It doesn't seem too complicated. Use the same equipment to ensure that everything is symmetric. Identical cable lengths to the combiner. Match polarities.

Two questions: Can someone provide a good example (model number) of a "low-loss combiner" for this application? I notice in the pictures that the antenna was angled up. Is that because that location was in a valley? My view is essentially flat to the horizon. Do I need to be angled down or is that just knit picking at this point?

Thanks again for your reply

I wonder especially as my signal strength seems to be stronger at night and in that case the signal is also much more stable. Is that a counter-indication of overload?

This is a good indication that you need a higher gain antenna.

I notice in the pictures that the antenna was angled up. Is that because that location was in a valley? My view is essentially flat to the horizon. Do I need to be angled down or is that just knit picking at this point?

Aim for the horizon.

dagger, the Quantum FX ANT 101 is a better antenna on both UHF and VHF HI, and VHF Low, than the Winegard SS 3000.

However it is a better than average indoor antenna. Seems like it will work for you, on a tricket shelf.

The Winegard SS3000 is into the -10 dBd range on VHF Hi (then add 10db amplification). The FX ANT 101 is about 0 dBd then add 36 db amplification. However you really should just be adding 3 dB amplification on either of them for the amplifier....but that gets a bit complicated.

Simply put the QFX ANT 101 is about 10 dB better than the Winegard SS3000 on VHF High.

If the Winegard ends up being unsatisfactory, there are options.

I had the information from tvfools.com up before but here it goes again, I'm only 13 miles form the city and something must have changed to take all the vhf channels away.


http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d03fb5cc5507be4

dagger,

Take another look at your Chart, your ABC/WABC, PBS/WNET and CW/WPIX are VHF stations. An Antenna is chosen to fulfill the channels in the "REAL" column. You have a couple other VHF stations available, but, I'd suggest you aiming for your 290°-304° Farms.
Given your overall low signal strength, you'd be better off with a Rooftop Antenna and a Pre-Amp. Can you do that?

VHF has difficulties penetrating into
modern homes due to the use of chicken wire in stucco and aluminized foil "wraps",allowing BETTER penetration of UHF freqs via window openings.

HOWEVER, I have also seen specs wherein modern "Low-E" glass attenuates UHFby about 20 dB (but no data wrt VHF!!!!).

IMO your link on free-space path loss (FSPL) is somewhat unrelated to the subject of penetration. We are more interested in trees, walls, and roofs than vacuum.

I'm an EE working with RF for over half century but must admit OTA TV is not my area of specialty. And RF, particularly high-frequency, can be very peculiar and unpredictable. But myself and most others in the field generally accept that low frequencies have much better penetration.

A RS S90 UHF/VHF yagi, when it was in the attic under asphalt roof, pulled in two VHF stations well but pretty much zilch on UHF. I cut off the small UHF yagi with it's reflector (1 minute job w/hacksaw) and mounted it on a pole outside the window. Suddenly 30 some additional UHF stations. Just for yucks I swapped positions and guess what? UHF back down the drain again.. little change in VHF. Both bands contain stations with similar TVfool strengths. This summarizes my only experience with TV reception and penetration.

Can't say too much about aluminized insulation or stucco grid other than mesh size is very wavelength dependent. Thick solid metal effects all frequencies similarly as far as penetration.

I do have significant experience with effects of glass on 72mhz, FMS/GMRS, GPS, FTA sat, XBee (900 and 2400), WiFi, etc.. I found glass will attenuate high frequencies far more than low. At least until you get past IR up into the visible. Try getting WiFi or FTA through a window. Much less of a problem with 72mhz or 400mhz.

My general impression is high frequencies are LOS with poor penetration while low is better at cutting through trees and roof. Of course UHF may be "better" from antenna size viewpoint but that's another subject.

To some the laws of physics are merely a suggestion. :) :) :)

Hey Einstien signals that have the most issues with indoor reception

1) Low-VHF
2) High VHF
3) UHF

Using your logic the opposite is true. Also it's amazing how my wireless G signal coming from my router that's at 2300 MHz( 3.5-5 times higher than the UHF TV band ) can be picked up in a house made of brick over 250 feet away. Amazing how cell phone signal can penetrate buildings. What frequency are they on again?

As some other guy said it's about the power levels. You just can't generically state that VHF can penetrate better than UHF without any other info.

Hey Einstien signals that have the most issues with indoor reception

1) Low-VHF
2) High VHF
3) UHF

Using your logic the opposite is true. Also it's amazing how my wireless G signal coming from my router that's at 2300 MHz( 3.5-5 times higher than the UHF TV band ) can be picked up in a house made of brick over 250 feet away. Amazing how cell phone signal can penetrate buildings. What frequency are they on again?

As some other guy said it's about the power levels. You just can't generically state that VHF can penetrate better than UHF without any other info.

Yes I can. Watch this:

"VHF can penetrate better than UHF"

Here, it is again, twice in a row:

"VHF can penetrate better than UHF"
"VHF can penetrate better than UHF"

:) :) :)

Apparently you've choosen to ignore my comment about "all else equal" (including power level). And then proceed to ignore it in your own examples.

"Lisa... In this house we OBEY the laws of thermodynamics" -Homer Simpson

Also it's amazing how my wireless G signal coming from my router that's at 2300 MHz( 3.5-5 times higher than the UHF TV band ) can be picked up in a house made of brick over 250 feet away.

BTW IEEE 802.11g is 2400mhz not 2300mhz. :)

Oops, I meant the Quantum FX ANT 102 is a better antenna than the Winegard SS3000 on VHF LO and HI and UHF.

Here's H&E paper (sec 6) citing a 1963 report that says NYC penetration loss is HIGHER for VHF than UHF:
http://www.copyright.gov/docs/shvera/comments/echostar-attach-B.pdf
Note that it mixes antenna height in with penetration loss, so it's hard to separate....
Counterintuitive? Yes. Accurate? Hard to say without access to the actual studies.
Unfortunately, recent studies in Europe have omitted VHF, cuz they apparently don't use it anymore....

Here's an example of current experts citing higher building penetration loss at VHF than UHF:
http://www.acrodyne.com/PDF/Portable_Means_Power.pdf

BTW: The free space loss equation was intended to show that it takes much less power at VHF
to provide the same receive signal strength as at UHF. This is the first step in determining
the DIFFERENCES between VHF and UHF, the others being antenna Gain (& VSWR Losses),
Penetration Loss and several others (Foliage Loss, Clutter Loss, et. al.)

====================================================
FYI: I posted links to (mostly UHF) Indoor Penetration Loss and Antenna Height Gain studies here:
http://www.avsforum.com/avs-vb/showthread.php?p=14035356

There is a more recent report on a very extensive indoor loss (and antenna height)
field test for UHF TV and summarizes results for some Cell Phone frequencies:
"Extensive Penetration Loss Measurements and Models for Different Building Types
for DVB-H in the UHF Band, Plets, Verloock Martens Gauderis & Deventer,
IEEE Trans on Broadcasting, Vol55 No2 Part I of II, June 2009 ":
http://ieeexplore.ieee.org/Xplore/login.jsp?reload=true&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F11%2F4976143%2 F04783077.pdf%3Farnumber%3D4783077&authDecision=-203

Test area was Ghent, Netherlands collecting data on a variety (100 total) of building types.
Results for more modern buildings may be higher due to use of foil wraps and Low-E glass.
For example, "Coated" Office Buildings had 20-25 dB loss on first two floors.

It also has a very useful list of references. Tables III & VI summarize 602 MHz results:
Normal House (aka "Mansion"): 8.2 dB (standard deviation = sigma=3.7 dB).
This is consistent with Apartment results, although with a much higher sigma.
[PS: Table III Total for Apartments is clearly in error.]
Literature average cited for House: 11 dB (sigma= 6 dB).

Penetration Loss decrease with increasing antenna height was also measured.

[QUOTE=holl_ands;17343477]Here's H&E paper (sec 6) citing a 1963 report that says NYC penetration loss is HIGHER for VHF than UHF:
http://www.copyright.gov/docs/shvera/comments/echostar-attach-B.pdf
Note that it mixes antenna height in with penetration loss, so it's hard to separate....
Counterintuitive? Yes. Accurate? Hard to say without access to the actual studies.
Unfortunately, recent studies in Europe have omitted VHF, cuz they apparently don't use it anymore....

Here's an example of current experts citing higher building penetration loss at VHF than UHF:
http://www.acrodyne.com/PDF/Portable_Means_Power.pdf
QUOTE]


Thanks for those links (let's face it you are go-to guy in that dept.). Very educational. I read and saved them to disk. However the Dishnetwork guys never provide UHF/VHF links or actual data but simply state:

"The largest impediments to the adoption of M/H service by VHF stations are the inferior gain of small handheld device antennas and, perhaps counter-intuitively, the increase in building penetration losses at these lower
frequencies. Both impediments are based upon the relative size of receive antennas and building apertures, such as outside windows, compared to the wavelength of the signal."

The fact that they use the term "counterintuitive" at all bolsters my point that with RF in general low freq has a rep for better penetration. And, again, my own experience dealt with attic and roof issues instead of antenna size and windows which seem to be the major factors in their conclusion.

The Sinclair/Acrodyne paper also states that building penetration is better for UHF but provide little basis other than referring to Bendovs site which seems more concerned with interference and hardware design.

It's true most of my "intuition" regarding TV comes from years of experience with other wavelengths. And maybe I'm biased because it's much harder to put the VHF antennas outside and allow little UHF ones indoors. My own experiment showed the opposite however. It would be interesting if others repeated a similar test (attic/roof not antenna size/apertures etc.).

May just be TV wavelengths have decided laws of physics are merely suggestions. :)

dagger,

Take another look at your Chart, your ABC/WABC, PBS/WNET and CW/WPIX are VHF stations. An Antenna is chosen to fulfill the channels in the "REAL" column. You have a couple other VHF stations available, but, I'd suggest you aiming for your 290°-304° Farms.
Given your overall low signal strength, you'd be better off with a Rooftop Antenna and a Pre-Amp. Can you do that?

Yes i know they are VHF, that is why all are lost now. Moved the Wineguard to about the same high as the Monoprice antenna was and all stations have returned. Try and find someone to install roof top antenna,3 people never showed so this looks like it will work out fine.

MTVhike,
Your request for comparison may be a moot point, I don't think that the CM-4248 is being made any more.

But to pursue some comparison...
Do you actually need a full range (Ch 2-69) or would HiVhf/UHF do ?
Would a Yagi Type or Bow Tie be better for your Mount/Location ? (depending on the answer of question 1)
Can you/your location handle a narrow (15°) Beamwidth, or did you plan to use a Rotator ?

These and probably many other questions about the requirements for your specific location (which should be the focus your search) can be answered if you go to...
TVFool Transmitter Locater (http://www.tvfool.com/?option=com_wrapper&Itemid=29)
and get the information about your location. Having done that, there's probably not going to be much "comparison" required. There's an Antenna that should clearly stand out, as being the right one for you.

Thanks, SWHouston. My question was intended to be more general. I already have the CM4248 installed inside my attic, with marginal success. On a few UHF stations, I get up to 70% signal strength (with a CM7777 preamp), but some I can't get at all. I know that a rooftop mount would be better, but for me, that is difficult. I was considering getting a 4228 and mounting it on the outside of the triangular end of my house - the normal to that surface is about 15 degrees away from the stations I wish to receive. However, if I can get onto my roof, I suspect a yagi might be better, maybe an Antennacraft MXU59.

I will get an Antennacraft Y10-7-13 antenna for high VHF purposes (I am currently using an external folded dipole, again with marginal success), and will connect it to the VHF input of the 7777.

Mike

I'm adding an second 8-bay antenna (AntennasDirect db8) to my antenna mast to make a 16-bay antenna as per the instructions on hdtvprimer.com as suggested to me on this forum.

In the primer for building a 16 bay it says: "There is a chance that you will mix up the polarities such that the two antennas subtract instead of add. After the antenna is fully hooked up, you should rotate the antenna to check for this pattern. If so then you have to reverse the connections on one of the antennas."

My question: The output of the AD DB8 is a 75 Ohm coax connection, not the 2-wire output of some antennas. With this setup, is polarity still an issue? If so, what is the solution? Turn the antenna upside down? Disconnect and turn the antenna's transformer box upside down?

I'll be using the Wingard CC 7870 2-way Antenna Joiner Coupler to join the signals.

Thanks, Dan

If it's a hard-wired PCB balun, then you'd assume it's correct. Some of those baluns simply have a ferrite balun inside a black box though so you might check.

You should easily be able to tell if the polarity is correct. If you are in phase, you have a strong forward lobe. In other words, you have a strong signal pointing directly at the station. If you are out of phase, you have a forward null with large side lobes. This means you'd get almost no signal pointing directly at the station but you'd get some signal pointing off-axis.

Presuming the assemblers ALWAYS connected the wires inside the same way and NEVER made a mistake.....
I would open up the Baluns and do a physical comparison.....

Presuming the assemblers ALWAYS connected the wires inside the same way and NEVER made a mistake.....
I would open up the Baluns and do a physical comparison.....

The DB8 baluns are PCBs, not any kind of ferrite balun.

Ken Nist has a photo on his website and it is accurate.

To reverse the polarity of one of the antennas, hang it upside down.

To reverse the polarity of one of the antennas, hang it upside down.


I like novel thinking. Very good idea.

I would open up the Baluns and do a physical comparison.....

And look for what exactly to indicate improper/proper phasing?

IF they are PCB baluns AND they aren't phased identically, I'd be looking for a different antenna manufacturer.

In practice, it's not difficult to tell whether the phasing is correct. If (in the case of a PCB balun) it's necessary to turn the antenna over to phase it properly for stacking I'd call the manufacturer and demand a properly manufactured antenna.

Remember that the length of coax must be exactly the same per antenna up to the combiner.

I try not to "ass-u-me" anything....
I wouldn't rule out A-D changing the Balun Box design, perhaps to improve Hi-VHF.....

Quick question... what's the advantage of using a joiner/coupler like the Wingard CC 7870 instead of a regular splitter used "backward"?

I have two antennas, a VHF-UHF and a UHF tied together with just a backward splitter. Would I get better results with a 7870?

Larry
SF

Quick question... what's the advantage of using a joiner/coupler like the Wingard CC 7870 instead of a regular splitter used "backward"?

I have two antennas, a VHF-UHF and a UHF tied together with just a backward splitter. Would I get better results with a 7870?

Larry
SF

Why are you using a VHF/UHF antenna and a seperate UHF antenna? Just curious. I have a VHF antenna, a 2 seperate UHF antennas (3 seperate antennas) and have found that (for me) this to be the best combo. I have VHF and UHF#1 joined using a UVSJ and I joined UHF#2 to UHF#1 via a balun on #2 and coax to another balun on UHF#1. I have 2 UHF 4 bay antennas to get reception from 2 different cities. I have been told it is a bad idea to join the 2 UHF antennas like this, but I get incredibly stable & excellent reception using this method.

Initially I did have reception issues, but I found that I had the 2 UHF antennas too close together. All antennas are on a 10' mast with the VHF at the top, then about 1 foot down (give or take) the first UHF antenna pointed towards one city and then another 1 foot (give or take) the 2nd UHF antenna pointed at the other city.

Here is a picture to give you an idea of what it looks like. The bottom antenna was repositioned after the picture was taken and is now down so the bottom reflector rod rests on top of the PVC vent pipe.
http://www.avsforum.com/avs-vb/attachment.php?attachmentid=151209&d=1251496414

LOL! You should fix that rain gutter. ;)

;) Yeah, its getting replaced here shortly.

Why are you using a VHF/UHF antenna and a seperate UHF antenna? Just curious.
I have a channel 12 plus UHF channels 27, 28, 40 and 41 in one direction where I use the combination antenna, and channel 7 plus several UHFs in another direction where I use just the UHF antenna. Channel 7 is strong enough to give me a 90 to 92% signal using just the UHF.

I have a VHF antenna, a 2 seperate UHF antennas (3 seperate antennas) and have found that (for me) this to be the best combo. I have VHF and UHF#1 joined using a UVSJ and I joined UHF#2 to UHF#1 via a balun on #2 and coax to another balun on UHF#1. I have 2 UHF 4 bay antennas to get reception from 2 different cities.
You lost me with that configuration! Glad it works for you.

I'm still wondering if a 7870 will give better results than just a backward splitter.

Larry
SF

You lost me with that configuration! Glad it works for you.

I'm still wondering if a 7870 will give better results than just a backward splitter.

Larry
SF

Larry, I figured I would lose you, thats why I posted the picture link for a vsual aid. ;)

Here is the important part of my description:
I joined UHF#2 to UHF#1 via a balun on #2 and coax to another balun on UHF#1.Point being that a splitter or combiner will cause more signal loss than the use of joining the antenna using a balun and a piece of coax and keeping the 2 antennas seperated by at least 1 foot. It worked for me, and is certainly worth a try for you in my humble opinion, as you won't know if it works unless you try.

However, to answer your specific question, the CC 7870 is nothing more than a splitter used as a combiner, with the exception that the 7870 is a mast mount design. Same insertion loss applies to both. So better results is very unlikely.

Re: Winegard CC-7870:
http://winegard.com/kbase/kb_tip_results.php?tip_num=291

Re: Winegard CC-7870:
http://winegard.com/kbase/kb_tip_results.php?tip_num=291

...which says it's nothing more than a backwards splitter inside that plastic case with a mast clamp...

ROFL!

...which says it's nothing more than a backwards splitter inside that plastic case with a mast clamp...

ROFL!

Which is exactly what I said already.;)

I won't change a thing. My backward splitter is working and apparently the CC-7870 is the same thing in a fancy box.

Thanks, guys!

Larry
SF

I have two antennas, a VHF-UHF and a UHF tied together with just a backward splitter. Would I get better results with a 7870?


In your case the better option is two feedlines and an A/B switch.

And look for what exactly to indicate improper/proper phasing?

IF they are PCB baluns AND they aren't phased identically, I'd be looking for a different antenna manufacturer.

In practice, it's not difficult to tell whether the phasing is correct. If (in the case of a PCB balun) it's necessary to turn the antenna over to phase it properly for stacking I'd call the manufacturer and demand a properly manufactured antenna.

Winegard's current manufacture PCB baluns are shipped in their own small boxes and can be plugged in either way, so if you are planning on stacking two of them in phase, you have to make sure that you plug both of them in the same way.

Thanks to all for the advice. I finally installed the second DB-8 this weekend and it seems to work well (enough). On a good reception day in the past, I was getting signal strength in the mid-60s (as rated by my DishNetwork DVR) with somewhat frequent dropout and bad days with no signal whatsoever (signal strength below mid-50s seems to be interpreted by the DVR as 0). Now signal strength seems to be in the mid-70s. It still bounces around a lot, but significantly less frequent drop outs. I'm hoping that the improvement is real and not just I've had some good reception days lately. Evening and nighttime reception is very good, hitting signal strength in the 80s and 90s.

I was a little disappointed to read earlier posts that the Wingard CC 7870 I installed is just a reverse splitter. 30% loss from each antenna seems to really limit the value of adding a second antenna. Fortunately it seems like I only needed a little bump in reception. Any other suggestions for more effective combining of signals?

Thanks again, Dan

I'm adding an second 8-bay antenna (AntennasDirect db8) to my antenna mast to make a 16-bay antenna as per the instructions on hdtvprimer.com as suggested to me on this forum.

In the primer for building a 16 bay it says: "There is a chance that you will mix up the polarities such that the two antennas subtract instead of add. After the antenna is fully hooked up, you should rotate the antenna to check for this pattern. If so then you have to reverse the connections on one of the antennas."

My question: The output of the AD DB8 is a 75 Ohm coax connection, not the 2-wire output of some antennas. With this setup, is polarity still an issue? If so, what is the solution? Turn the antenna upside down? Disconnect and turn the antenna's transformer box upside down?

I'll be using the Wingard CC 7870 2-way Antenna Joiner Coupler to join the signals.

Thanks, Dan

30%? Where'd you get that number from? Try losing 50%. A 2 way splitter cuts the power in half. What you want to do is install a LOW NOISE pre-amp or a low noise amp. Typically a gain of 15dB and should recover what you are losing.

I was a little disappointed to read earlier posts that the Wingard CC 7870 I installed is just a reverse splitter. 30% loss from each antenna seems to really limit the value of adding a second antenna. Any other suggestions for more effective combining of signals?

The previous post referred to adding two antennas aimed in two directions. I believe that you are trying to add gain to an existing antenna using a second antenna in the same direction.

The CC7870 is the right coupler for you. There will be signal addition, not loss.

The previous post referred to adding two antennas aimed in two directions. I believe that you are trying to add gain to an existing antenna using a second antenna in the same direction.

The CC7870 is the right coupler for you. There will be signal addition, not loss.

Yes. If you get the antennas and feedlines arranged so that the signals are in phase, you can acheive a theoretical doubling of the signal instead of a halving. In practice, if you get 2.5 dB improvement, you've done very well.

If the antennas are not phased together, then you suffer the loss.

30%? Where'd you get that number from? Try losing 50%. A 2 way splitter cuts the power in half. What you want to do is install a LOW NOISE pre-amp or a low noise amp. Typically a gain of 15dB and should recover what you are losing.

That was from the manufacturer referenced in an earlier post.

http://winegard.com/kbase/kb_tip_results.php?tip_num=291

This is a splitter being used as a combiner.

Yes. If you get the antennas and feedlines arranged so that the signals are in phase, you can acheive a theoretical doubling of the signal instead of a halving. In practice, if you get 2.5 dB improvement, you've done very well.

If the antennas are not phased together, then you suffer the loss.

Yes, I'm getting an overall improvement of signal. The "loss" I was referring to is of the theoretical potential of each individual antenna without a combiner. So instead of getting twice the signal of a single antenna, I'm getting 70% from EACH individual antenna (because of losses in the combiner), adding to something like 140% of the signal I was getting with only one antenna.

What I was asking was whether there was a way to combine the antennas before the transformer box that connects to the cable wire so that you don't need the 7870 combiner (and the associated signal loss) getting closer to the theoretical doubling of total signal. Or does any method of connecting the two result in a similar magnitude of "combiner loss"?

It's really just a theoretical question. I'm pretty happy with the results that I achieved in combining the antennas as I did.

That was from the manufacturer referenced in an earlier post.

http://winegard.com/kbase/kb_tip_results.php?tip_num=291

This is a splitter being used as a combiner.

I understand. But the problem is, the loss thru the splitter is the same even when used as a combiner. That "tech tip" is correct that there is a loss, but wrong on the amount of the loss.

It's really just a theoretical question. I'm pretty happy with the results that I achieved in combining the antennas as I did.Ultimately that is all that matters, that it works for you.

In my situation, I have 2 UHF antennas pointed in different directions. To join them, I did like you, used a 2 way of high quality as a combiner. The resulting loss of signal was just too great to overcome, even with the use of a +15dB pre-amp. My solution is one that I have already explained and is looked upon as the wrong way that "will do more harm than good". So as I said, in the end the only thing that matters is how it works for YOU. :)

Even though it is working well for you, you are only getting 50% from each antenna since you are running it thru the splitter/combiner. You can still of course have your 'gain' that will makeup for the loss, but it depends on the actual gain as to how much of the loss is overcome. In your case, what you really have achieved is not so much a gain in signal strength, but rather a greater area of reception since you have effectively 'enlarged' the 'capture' area.

Again, what matters is that it works for you and you are satisfied.

In your case the better option is two feedlines and an A/B switch.

Not when the feed is for a DVR. You have to get all of the stations all of the time, or you're sure to miss something by having the switch in the wrong position.

I have an A-B-C switch for the rest of my system where I can choose from three different antenna systems. You ought to see the antennas on my roof!
A=CM4228 on rotor, B=another CM4228 with Y-10-7-13 on rotor, C=Antennas Direct C5. The antennas for the DVR are a Radio Shack VHF-UHF combo and an Antennas Direct SR-15 UHF tied together with the backward splitter.

This way I get reliable recordings while at the same time I can play around with the other antennas to pull in the more distant stations on the TV. I do have an A-B switch on the input of the DVR in case I want to record a distant station, but normally the switch is left in the A position with the fixed antennas.

It works for me.

Larry
SF

Even though it is working well for you, you are only getting 50% from each antenna since you are running it thru the splitter/combiner.

Not true. You will get 100% of the signal from each antenna, less the loss inherent in the combiner, about .5dB. or about 12%. If the signals are in phase, they will sum. That is why you can get about 2.5 dB if you properly combine the signals of two identical antennas. If they are totally out of phase they will cancel. And if somewhere in between, the result will be in between.

If you get a given channel only from one of the antennas, you will have about 12% less signal strength after going through the combiner than if the combiner was not there, or about 84%.

Not true. You will get 100% of the signal from each antenna, less the loss inherent in the combiner, about .5dB. or about 12%. If the signals are in phase, they will sum. That is why you can get about 2.5 dB if you properly combine the signals of two identical antennas. If they are totally out of phase they will cancel. And if somewhere in between, the result will be in between.

If you get a given channel only from one of the antennas, you will have about 12% less signal strength after going through the combiner than if the combiner was not there, or about 84%.

100% of each antenna before the splitter. The loss in any 2 way splitter is 3.5dB and at each connection point is .5dB. Don't know where you got the idea that the loss thru a splitter/combiner (which is one and the same) is only .5dB. There isn't a reduction in the splitters loss when turned around and used as a combiner. You will lose 3.5dB on each input leg. IE...5dB in = approx 1.5dB out. The 5dB figure includes the 2.5dB gain. Without that gain, and a 2.5dB input leaves you with -1dB output.

Splitter with 3.5dB insertion loss:

10.5dB input gives two 7 dB outputs. 3dB reduction in each output is due to splitting signal in two. .5dB is due to losses in the splitter.

Same device used as combiner:

Two 7dB inputs sum to 10dB. .5dB lost in the splitter. Output is 9.5dB. Net gain from using two identical inputs is 2.5dB.

LOL! What the hell is this:
Splitter with 3.5dB insertion loss:

10.5dB .5dB ---------------7dB out
from -------------- loss from
source splitter ---------------7dB out

3dB of the insertion loss is due to splitting the signal in two. .5dB is loss inherent to the splitter.

Same device used as combiner

7dB source--------------.5dB
loss from----------9.5 dB out
7dB source--------------splitter

Splitter with 3.5dB insertion loss:

10.5dB input gives two 7 dB outputs. 3dB reduction in each output is due to splitting signal in two. .5dB is due to losses in the splitter.

Same device used as combiner:

Two 7dB inputs sum to 10dB. .5dB lost in the splitter. Output is 9.5dB. Net gain from using two identical inputs is 2.5dB.

:eek:LOL! Sorry partner. A passive combiner does not raise/add signal level. Quite the opposite really.

Then please explain how some members here combine two identical antennas properly spaced and pointed in the same direction using a passive combiner to get 2.5dB gain.

Or please explain how I can combine a VHF antenna and a UHF antenna with a passive device and not more than halve the signal from either one.

Then please explain how some members here combine two identical antennas properly spaced and pointed in the same direction using a passive combiner to get 2.5dB gain.

Or please explain how I can combine a VHF antenna and a UHF antenna with a passive device and not more than halve the signal from either one.


Answer #1 read this http://www.hdtvprimer.com/ANTENNAS/16bay.html

Answer #2 use a UVSJ.

Then please explain how some members here combine two identical antennas properly spaced and pointed in the same direction using a passive combiner to get 2.5dB gain.

I'm not saying you can't get a +2.5dB gain using 2 antennas instead of a single antenna. I am saying that using a 2 way splitter as a combiner will net a loss of -3.5dB the same as when used as a splitter. You are saying there is only a loss of -.5dB when a splitter is used as a combiner and it just doesn't work that way.

Or please explain how I can combine a VHF antenna and a UHF antenna with a passive device and not more than halve the signal from either one.

Just noticed you added more to your post. And now you have me confused. This whole time our discussion has been about 2 of the same antennas, or at least that was the impression I was under. And now you are talking about joining VHF and UHF antennas that are not the same. So which is it?

To correctly join a VHF & UHF antenna, as has been said in post 1661, a UVSJ is needed. A UVSY is not the same as a splitter and as such has lower loss.

I have 2 antennas that are the same, but aimed in different directions, as well as a VHF antenna and they are joined using baluns and a UVSJ. See my earlier post in this thread for details and photos.

:eek:LOL! Sorry partner. A passive combiner does not raise/add signal level. Quite the opposite really.

LOL right back at you. You're the one that's wrong.

Ron

Not true. You will get 100% of the signal from each antenna, less the loss inherent in the combiner, about .5dB. or about 12%. If the signals are in phase, they will sum. That is why you can get about 2.5 dB if you properly combine the signals of two identical antennas. If they are totally out of phase they will cancel. And if somewhere in between, the result will be in between.

If you get a given channel only from one of the antennas, you will have about 12% less signal strength after going through the combiner than if the combiner was not there, or about 84%.

Colm is 100% correct. I think why splicer010 isn't seeing this is because according to his post "In my situation, I have 2 UHF antennas pointed in different directions" doing this will result in losses. As Clom said above the signals must be in phase(exact same antennas and pointed in the exact same direction). The only way you can have different antennas pointed in different directions and see appreciable gains is if each antenna is a different band(UHF/VHF, VHF high/VHF low, etc.) or separate channel antennas in conjunction with the correct combiners(not just a regular splitter). In this case you will be seeing only particular frequencies on each antenna, they won't be combining same frequency's for a net gain.
Again if you you have a strong enough signal you may have luck with 2 different antennas pointed in 2 different directions with just a simple backwards splitter(in which case that might be good enough for you) but you'd have even better luck doing it correctly.

I'd like to build an antenna for my attic to receive OTA signals. According to AntennaWeb I need a "Yellow" type antenna. Is the basic 4-bay DIY antenna the best for my purposes? The 1st post hasn't been updated in years so I figured I'd post.

Hi jjeff. I have 2 UHF antennas that are identical make/model but pointed in different directions. Just so you are clear on what I am using. ;)

Quote:
Originally Posted by Splicer010
LOL! Sorry partner. A passive combiner does not raise/add signal level. Quite the opposite really.
LOL right back at you. You're the one that's wrong.

RonToo funny. Please explain to me and everyone else Ron, just how a passive combiner itself can raise/add signal level then.

I'd like to build an antenna for my attic to receive OTA signals. According to AntennaWeb I need a "Yellow" type antenna. Is the basic 4-bay DIY antenna the best for my purposes? The 1st post hasn't been updated in years so I figured I'd post.What channels do you wish to receive VHF, UHF or both?

What channels do you wish to receive VHF, UHF or both?
I'm not sure really. I'd like to receive HD OTA channels, but I don't know if they're broadcast in UHF or VHF in my area.

I'm not sure really. I'd like to receive HD OTA channels, but I don't know if they're broadcast in UHF or VHF in my area.
Try the below site, just put your zipcode in the form and it will generate a list of the channels available in your area.

http://www.tvfool.com/index.php?option=com_wrapper&Itemid=29

Try the below site, just put your zipcode in the form and it will generate a list of the channels available in your area.

http://www.tvfool.com/index.php?option=com_wrapper&Itemid=29
Ok, got it. I'm only interested in the major networks like ABC, NBC, FOX, etc. It doesn't look like much else that I'd normally watch anyways. I'm only 13 miles form the transmitter so I'm pretty close. How can I tell if these stations are UHF or VHF now?

http://i168.photobucket.com/albums/u177/superorb/Misc/Radar-Digital.jpg

See the two charts at the bottom? There's one for VHF and another for UHF.

It looks to me like all your major nets, CBS, NBC, PBS, FOX, CW are all UHF and the ABC channel is VHF.

See the two charts at the bottom? There's one for VHF and another for UHF.

It looks to me like all your major nets, CBS, NBC, PBS, FOX, CW are all UHF and the ABC channel is VHF.
So it looks like all UHF with the exception of 1 station on the High VHF scale.

So it looks like all UHF with the exception of 1 station on the High VHF scale.

That's what I see, yes.

That's what I see, yes.
So back to my original question, what would be the most effective antenna for me to build provided it will live in the attic out of sight? Thanks for the help thus far.

So back to my original question, what would be the most effective antenna for me to build provided it will live in the attic out of sight? Thanks for the help thus far.

At 13 miles with line of sight you're not going need much. I use a 91XG myself but that's because I'm a good 60 miles from the transmitter. Hopefully some folks here more familiar with close range antennas will give you some recommendations.

So back to my original question, what would be the most effective antenna for me to build provided it will live in the attic out of sight? Thanks for the help thus far.

I don't know that a single aim will be possible for all of your channels, such as PBS. You might want to try a single classic bowtie near a window first. I know it is a UHF antenna, but the flat wire also acts as an antenna. I've reliably received rf 9 (Nm db 54) with a bowtie for over a month now. You've got stronger signal there than I have here. It might work. Good Luck.

Too funny. Please explain to me and everyone else Ron, just how a passive combiner itself can raise/add signal level then.

?

The -3.5db loss on each leg is if it is used to split the signal or assuming lack of phasing if used as a combiner. 3db is 50 percent loss due to the split (or incorrect phase) and .5 db is through-loss.

However, if you phase properly with two identical antennas pointed in the same direction and equal coax lengths to the combiner you'll see increased performance over a single antenna even using a common splitter. The problem is that common splitters just don't phase very well no matter what. That's the reason stripline combiners work better.

In your situation with the antennas pointed in different directions, the -3.5 db loss should be roughly accurate. Additionally, though, you generate multipath which is the reason it would be technically better to use an A/B switch and two downleads.

Yesterday, I installed two Winegard antennas - YA-1713 high VHF, and a 9095P UHF. Each has a plastic box with a PC board balun, to provide 75 ohm connections. However, the UHF one also has a connector for a VHF antenna, so I guess that is a combiner also. I am using a CM7777 preamp with dual inputs, so I don't use the combiner mounted on the UHF antenna, so I put a 75 ohm cap on that input. How does this configuration relate to the discussions above?

This appears to work well, pulling in WNJN RF 51 in New Jersey, 55 miles away fairly well. I still don't get WCBS RF 22 or WWOR RF 38 (I get all the other NYC stations, as well as some CT ones). Tomorrow, I am getting a 24 ft mast to raise this assembly (currently the VHF one is about 1 ft above my porch roof, and the UHF one is below it - my current 10 foot mast is mounted on my deck). Any suggestions? I'll post a photo of this assembly when I can get one (it's nightime now).

I don't know that a single aim will be possible for all of your channels, such as PBS. You might want to try a single classic bowtie near a window first. I know it is a UHF antenna, but the flat wire also acts as an antenna. I've reliably received rf 9 (Nm db 54) with a bowtie for over a month now. You've got stronger signal there than I have here. It might work. Good Luck.
I'm only interested in the major networks like ABC, NBC, FOX, CBS.

So back to my original question, what would be the most effective antenna for me to build provided it will live in the attic out of sight? Thanks for the help thus far.Before you build one, you might want to try this specific model (Catalog # 15-1874) indoor VHF/UHF antenna (http://www.radioshack.com/product/index.jsp?productId=2103077) which is very inexpensive and has worked quite well for many AVSForum members that are not very far from the towers.. You can use it indoors or (better) in the attic, with a coax extension.

The loop part of the antenna is for all the UHF channels. The dipole "rods" are for the lone VHF (abc) channel in your area. Extend each rod about 13" each and in a "V". Aim the antenna perpendicular to the towers.

If it doesn't work, just return it for a refund and come back here for more suggestions.

I'm only interested in the major networks like ABC, NBC, FOX, CBS.

If the top 6 channels on your tvfool chart are all that you need, then you probably won't need multiple aims. I can only say probably though. If multiple aims are required, these are easier to accomplish if the antenna is not in the attic. If multiple aims are not required, then a single trip to the attic should do the trick. The RS budget antenna is both VHF and UHF and probably a good bet. You might also be able to receive those top 6 channels with a pair of rabbit ears alone. Yes, rabbit ears do pick up UHF signal as well.
I'm watching Fox on rf 40 right now with a pair.

Too funny. Please explain to me and everyone else Ron, just how a passive combiner itself can raise/add signal level then.
It's simple. A splitter is a reciprocal device. The input and outputs ports are interchangeable. As a splitter, if we apply 10 microwatts to the input port, we get (ignoring losses for now) 5 microwatts on each output port. As a combiner, if we apply 5 microwatts to each input port, we get 10 microwatts on the output port.

What is so difficult to believe about that?

http://www.w8ji.com/combiner_and_splitters.htm

Ron

It's simple. A splitter is a reciprocal device. The input and outputs ports are interchangeable. As a splitter, if we apply 10 microwatts to the input port, we get (ignoring losses for now) 5 microwatts on each output port. As a combiner, if we apply 5 microwatts to each input port, we get 10 microwatts on the output port.

What is so difficult to believe about that?

http://www.w8ji.com/combiner_and_splitters.htm

Ron

:rolleyes: Incredible. I hope you aren't really a dr and just play one on the internet. I know exactly what a splitter is and what it does. I've only used them professionally for 27+ years. Nobody here that I am aware of, including myself, has ever denied the fact that combining 5+5=10 on the output. The whole point is that a PASSIVE combiner cannot add or raise the signal. The ONLY way to raise the signal is to raise the input level. I'll say it again, it is IMPOSSIBLE for a PASSIVE combiner to raise/add signal level on its own. The key word is PASSIVE. Now if you are talking about an ACTIVE combiner (and you are not) that would be a different story.

Nobody here that I am aware of, including myself, has ever denied the fact that combining 5+5=10 on the output.
You disagreed with Colm, yet he is saying exactly the same thing. 5 + 5 = 10. I'm not sure what your point really is.

Ron

You disagreed with Colm, yet he is saying exactly the same thing. 5 + 5 = 10. I'm not sure what your point really is.

Ron

Ummmm, you really should read the entire conversation before you just jump in and say to me:You're the one that's wrong.
Had you done so you would have seen that this is what I was saying:I'm not saying you can't get a +2.5dB gain using 2 antennas instead of a single antenna. I am saying that using a 2 way splitter as a combiner will net a loss of -3.5dB the same as when used as a splitter. You are saying there is only a loss of -.5dB when a splitter is used as a combiner and it just doesn't work that way.Colm is stating that instead of a -3.5dB loss when used as a splitter, that when used as a combiner the loss is +3dB less and is only -.5dB. I corrected him and you are saying I am wrong, when it is the both of you that is wrong. That has been, and remains still as my point.

And since this has been so blown out of proportion and you guys seem so confused about all this, and post pointless links about combiners, then this will really blow your minds: The -3.5dB loss is PER LEG and not the total loss.

Are you saying that splitters and combiners are two different things?

Ron

Are you saying that splitters and combiners are two different things?

Ron

:rolleyes:Are you just being a troll or what? Because now it is my turn to ask, what is your point? :confused:

Did you bother to do what I told you about reading the whole conversation before jumping into it? Ehhhhh...no. I didn't believe you did. So go back and read the WHOLE conversation from the BEGINNING Ron.:rolleyes:

:rolleyes:Are you just being a troll or what? Because now it is my turn to ask, what is your point? :confused:

Did you bother to do what I told you about reading the whole conversation before jumping into it? Ehhhhh...no. I didn't believe you did. So go back and read the WHOLE conversation from the BEGINNING Ron.:rolleyes:
I'm not trying to be a troll and I have read the whole conversation. I'm just trying to clearly understand where you're coming from.

On one hand, you agree that a combiner can add two 5 microwatt signals to produce a 10 microwatt signal (ignoring losses). On the other hand, you state that a splitter being used as a combiner will attenuate each leg by 3 dB, therefore applying two 5 microwatt signals will produce 2.5 + 2.5 = 5 microwatts.

So I asked you, "are splitters and combiners two different things?" because that is what you are implying.

Ron

A combiner is a splitter.

On one hand, you agree that a combiner can add to two 5 microwatt signals to produce a 10 microwatt signal (ignoring losses). On the other hand, you state that a splitter being used as a combiner will attenuate each leg by 3 dB, therefore applying two 5 microwatt signals will produce 2.5 + 2.5 = 5 microwatts.Ehhhhhhh...no. Ignoring losses then 5 in + 5 in = 10 out. Not ignoring losses then 5 in + 5 in = 3 out. This really isn't complicated as you are trolling, err, trying to make it.

And you ask me why I can't understand.:rolleyes:

A combiner is a splitter.
Okay, that's a starting point. Then why is the loss entirely different in one direction versus the other? How can a passive network know about direction?

As a splitter, the loss is 3.5 dB per leg. We put in 10 microwatts on the input and we get 4.47 microwatts on each output. The total loss is 10 - 4.47 - 4.47 = 1.06 microwatts or 0.5 dB.

As a combiner, the total loss is the same. We put in 5 microwatts on each input and get 5 + 5 = 10 microwatts minus 0.5 dB or 8.91 microwatts on the output.

Ron

:rolleyes: Incredible. I hope you aren't really a dr and just play one on the internet. I know exactly what a splitter is and what it does. I've only used them professionally for 27+ years. Nobody here that I am aware of, including myself, has ever denied the fact that combining 5+5=10 on the output. The whole point is that a PASSIVE combiner cannot add or raise the signal. The ONLY way to raise the signal is to raise the input level. I'll say it again, it is IMPOSSIBLE for a PASSIVE combiner to raise/add signal level on its own. The key word is PASSIVE. Now if you are talking about an ACTIVE combiner (and you are not) that would be a different story.

I think I'm with dr1394 on this one, FWIW (maybe not much; I'm no expert).

Have you ever heard of a transformer? They're used to step voltage up as well as down, and they're passive. They do have some inherent losses going either way, of course, but that may only be a few percent. They work fine for the power company, among others.

...then this will really blow your minds: The -3.5dB loss is PER LEG and not the total loss.That is simply not true in theory (or in practice) when using a typical hybrid splitter/combiner in the fine art of ganging or stacking phased antennas. :)

Think about it... if you are only getting half of each whole antenna (plus some loss) then the stacked duo would have less gain than the single whole, and there would generally be little benefit to doing it phased beyond some nulls.

You and Colm are really both half correct. In your configuration you are losing up to -3.5 per leg not -.5 per Colm. But when both legs are in phase and equal then it instead approaches +2.5 after the -.5 loss and this is why the hybrid splitter/combiner can be so effective for such application.


Now they sure aren't all created equal and I'd still rather have a stripline to play around with, but with careful attention to phasing the simple 49 cent hybrid T works wonders with both improved gain and desired nulls used with a perfectly balanced gang of two.


Read this section about Superposition analysis (http://www.hdtvprimer.com/ANTENNAS/ganging.html) to get better idea how the circuit behaves in these two different situations.

...The doubling of the output power is equivalent to a 3 dB increase in the signal. If the combiner is 90% efficient then a 2.5 dB gain is seen. Note the dichotomy:

· If the antennas point in different directions, there is a 3.5 dB loss at the combiner.

· If the antennas point in the same direction, there is a 2.5 dB gain at the combiner.

This is a 6 dB swing. 3 dB of this is just the adding of the second antenna, but the other 3 dB is from the combiner becoming a much more effective device.

Obviously in such case the loss is not -3.5dB PER LEG and field experience backs up the good dr's theory here.

If you don't still don't believe it try both configurations (matched same direction, unmatched different directions) for yourself. :)

http://i32.tinypic.com/20rkxoh.jpg

Can't we all just get along?

superorb,

HA ! :D, "Get Along", you GOT to be kidding ! :eek:

Agreed, you can get along with a Modified Range (Ch7-69) Antenna.

Additionally, from what I see on your Chart, and knowing that at times one really likes to "look around", you'd be limiting your Channel selection a lot, by getting a relatively Directional Antenna.

If you want to pick up that WRPX Ion AND your Majors without Rotating, you might think about one of the Omni's.

Just to get you started in that direction, take a look at...
Winegard MS2002 (http://www.solidsignal.com/prod_display.asp?prod=MS2002)

Then, at the bottom of the above Page/Link, there are several other applicable Antennas listed. Check um out !

Have a good Day ! :)
S.W.

superorb,

HA ! :D, "Get Along", you GOT to be kidding ! :eek:

Agreed, you can get along with a Modified Range (Ch7-69) Antenna.

Additionally, from what I see on your Chart, and knowing that at times one really likes to "look around", you'd be limiting your Channel selection a lot, by getting a relatively Directional Antenna.

If you want to pick up that WRPX Ion AND your Majors without Rotating, you might think about one of the Omni's.

Just to get you started in that direction, take a look at...
Winegard MS2002 (http://www.solidsignal.com/prod_display.asp?prod=MS2002)

Then, at the bottom of the above Page/Link, there are several other applicable Antennas listed. Check um out !

Have a good Day ! :)
S.W.
I'm not against an Omni, but I am against the $50 price. I'd like to limit it to $25 shipped if possible.

superorb,

Ok then, this is close, look at the...
Winegard HD7000R (http://www.solidsignal.com/pview.asp?mc=03&p=HD-7000R&d=Winegard-HD7000R-VHFUHFFM-DTV-TV-Antenna-(HD7000R)&c=TV%20Antennas&sku=615798398965)

You can just aim it at your Magnetic 124°, and enjoy !

Have a good Day ! :)
S.W.

superorb,

Ok then, this is close, look at the...
Winegard HD7000R (http://www.solidsignal.com/pview.asp?mc=03&p=HD-7000R&d=Winegard-HD7000R-VHFUHFFM-DTV-TV-Antenna-(HD7000R)&c=TV%20Antennas&sku=615798398965)

You can just aim it at your Magnetic 124°, and enjoy !

Have a good Day ! :)
S.W.
Anything that's $25 after shipping? I found this 2-Bay Bowtie Antenna (http://www.summitsource.com/directv-2-bay-uhf-antenna-hdtv-digital-channel-14-69-by-eagle-aspen-dtv2buhf-two-bay-hd-bowtie-tv-outdoor-roof-top-local-signal-bow-tie-aerial-red-zone-part-dtv2buhf-p-6754.html) for $24.xx shipped.

Superorb,

Follow Arxaw's suggestion. He knows his stuff. His recommendation should work well for you and is priced at half your $25 limit.

2-Bay Bowtie Antenna for $24.xx shipped.

That antenna is not designed to receive VHF. WTVD is on VHF. If you try to go any cheaper than the suggestions, be prepared to have reception issues with WTVD.

The Antennacraft HBU-22 is another cheap antenna that will receive WTVD.

Superorb,

Follow Arxaw's suggestion. He knows his stuff. His recommendation should work well for you and is priced at half your $25 limit.
Alright, I'll give the RS antenna a shot.

I'd like to build an antenna for my attic to receive OTA signals. According to AntennaWeb I need a "Yellow" type antenna. Is the basic 4-bay DIY antenna the best for my purposes? The 1st post hasn't been updated in years so I figured I'd post.

Excuse me, but, the...
Radio Shack T#749 (http://www.radioshack.com/product/index.jsp?productId=2103077)
is an Indoor (top of TV) Antenna, no wonder it's cheaper.
Nothing that I recall was ever said about an Indoor Antenna.
I don't know if this little guy has enough punch to get through the shingles, apparently you've changed your mind,
and as Arxaw suggests, use it on top of the TV ?

Have a good Day ! :)
S.W.

Excuse me, but, the...
Radio Shack T#749 (http://www.radioshack.com/product/index.jsp?productId=2103077)
is an Indoor (top of TV) Antenna, no wonder it's cheaper.
Nothing that I recall was ever said about an Indoor Antenna.
I don't know if this little guy has enough punch to get through the shingles !

Have a good Day ! :)
S.W.
Please look at post #1681. (http://www.avsforum.com/avs-vb/showthread.php?p=17539740#post17539740)

superorb,
thanks.

Using the suggested antenna (http://www.radioshack.com/product/index.jsp?productId=2103077) in the attic may help isolate it from all the RF noise from your TV and other nearby electronics in your home that can muck with VHF reception. In the past, when I lived fairly close to TV towers, using a similar "indoor" antenna in the attic worked very well for nearby VHF & UHF stations. I believe this particular antenna is somewhat better than the one I used, mainly because the UHF loop is larger than most others.

If it doesn't work, it's cheap and it's returnable.

Anything that's $25 after shipping? I found this 2-Bay Bowtie Antenna (http://www.summitsource.com/directv-2-bay-uhf-antenna-hdtv-digital-channel-14-69-by-eagle-aspen-dtv2buhf-two-bay-hd-bowtie-tv-outdoor-roof-top-local-signal-bow-tie-aerial-red-zone-part-dtv2buhf-p-6754.html) for $24.xx shipped.

And I can tell by the gains they list that it's not optimized for the new UHF channels since it gives the best gain at CH 69. I can make the same antenna actually optimized for 14-51 for about 1/3 of that or less.

But it's UHF-only.

superorb,
thanks.

Using the suggested antenna (http://www.radioshack.com/product/index.jsp?productId=2103077) in the attic may help isolate it from all the RF noise from your TV and other nearby electronics in your home that can muck with VHF reception. In the past, when I lived fairly close to TV towers, using a similar "indoor" antenna in the attic worked very well for nearby VHF & UHF stations. I believe this particular antenna is somewhat better than the one I used, mainly because the UHF loop is larger than most others.

If it doesn't work, it's cheap and it's returnable.
I picked up the RS antenna and I'll give it a shot tonight.

And I can tell by the gains they list that it's not optimized for the new UHF channels since it gives the best gain at CH 69. I can make the same antenna actually optimized for 14-51 for about 1/3 of that or less.

What specs do you recommend for a 2-bay? I've built a mclapp 2 bay with 10 inch whiskers, 9.5 inch bay spacing, and 1-3/4 inch phase line spacing. It works very well on UHF, about 3 dB less than a mclapp 4-bay. Unfortunately, high VHF really takes a hit on the two bay, especially if you add a reflector. Have you seen these same issues?

Thanks!

Rick

IMPOSSIBLE[/B] for a PASSIVE combiner to raise/add signal level on its own. The key word is PASSIVE. Now if you are talking about an ACTIVE combiner (and you are not) that would be a different story.

If you combine two antennas properly then you get more signal than that of one antenna. How close you get to the theoretical doubling of the signal (3db) depends on how well it is done.

I'm not sure of exactly what you are trying to argue at this point.:confused:

What specs do you recommend for a 2-bay? I've built a mclapp 2 bay with 10 inch whiskers, 9.5 inch bay spacing, and 1-3/4 inch phase line spacing. It works very well on UHF, about 3 dB less than a mclapp 4-bay. Unfortunately, high VHF really takes a hit on the two bay, especially if you add a reflector. Have you seen these same issues?

Thanks!

Rick

Well to be honest based on my own experience I think if you want high VHF you need to go with the 4 bay. I'm not sure there is a way around that short of making a 2 bay specifically for hi-VHF then you're talking about 28 inch whiskers. Of course I have no idea what the phase-line separation for that would be. Might be fun just to try.

I will say that when using a non solid reflector on either a 2 bay or 4 bay I get better signal strength from hi-VHF when the antenna facing backwards from the station. I am not sure why.

thanks BCF68! I've never tried reception from the back side. I'll give it a try! :)

Best,

Rick

Again, the take home about using common splitters as combiners in antenna stacking is that they simply don't PHASE very well. That's what stripline combiners are for. Using a common splitter can still work though when doing a dual stack---and provide increased gain as well as narrower beamwidth in the plane of stacking.

To illustrate the difference in the phasing properties b/w common splitters and a stripline, just try using a 4-way common splitter to do a quad. It just doesn't work at all, again not because of signal loss per se, but rather the 4-way just won't phase the signals. Use 3 two-ways though and it will work, although not nearly as good as a stripline will.

I'm not sure there is a way around that short of making a 2 bay specifically for hi-VHF then you're talking about 28 inch whiskers. Of course I have no idea what the phase-line separation for that would be. Might be fun just to try.



Theoretically, the phasing lines should be the same diameter and separation as the UHF version.

Cheap RS antenna is hooked up and I can tune CBS, NBC, ABC and FOX with a little distortion on each depending on the direction the antenna is pointed. I've got it between the TV nd a speaker, and it's sitting on top of a subwoofer. Signal was worse behind the TV. I think I'll buy a coax coupler and extent the cable into the attic to see if signal improves.

I must say, though, that OTA broadcasts in HD look stunning. Thanks for all the help guys.

Cheap RS antenna is hooked up and I can tune CBS, NBC, ABC and FOX with a little distortion on each depending on the direction the antenna is pointed. I've got it between the TV nd a speaker, and it's sitting on top of a subwoofer. Signal was worse behind the TV. I think I'll buy a coax coupler and extent the cable into the attic to see if signal improves.
As to be expected. All the electronics in the room give off a lot of noise that affects indoor reception. If the antenna is in an interior room of your house, away from exterior walls, the attic trial should give you better results.

Use as short a length as possible of RG6 coaxial cable and a "barrel splice (http://i25.tinypic.com/2pq5bpe.jpg)" to join it to the antenna. Do not use a splitter.

Make sure the dipole rods are not extended longer than they should be for your VHF channel (~14" each). Point the antenna like this:
http://i48.tinypic.com/23tjxhw.jpg
In your case, the red arrows are NW and SE
The rods should be in a much wider "V" than shown in this picture.

^^ Aiming it NW/SE doesn't seem to work as well as if I aimed it N/S for some reason. I don't mind getting up and rotating it based on the show I'm watching though. When I get around to buying a taller ladder I'll move it to the attic.

^^ Aiming it NW/SE doesn't seem to work as well as if I aimed it N/S for some reason. I don't mind getting up and rotating it based on the show I'm watching though. When I get around to buying a taller ladder I'll move it to the attic.Indoors, you may be using reflected signals, requiring aiming the antenna in a direction other than toward the towers. This type of antenna is not as directional as some others. So often times, where you have it sitting may be more important than what direction it's facing.

Until you get a ladder for the attic, you can experiment by moving the antenna around the room or to an adjacent room, using a longer piece of coax. Try different heights - from up near the ceiling to down on the floor. An exterior wall and near a window is usually best. With a little patience, you may find an interference-free hot spot for all your channels, so you won't have to keep mucking with the antenna.

Again, the take home about using common splitters as combiners in antenna stacking is that they simply don't PHASE very well. That's what stripline combiners are for. Using a common splitter can still work though when doing a dual stack---and provide increased gain as well as narrower beamwidth in the plane of stacking.

To illustrate the difference in the phasing properties b/w common splitters and a stripline, just try using a 4-way common splitter to do a quad. It just doesn't work at all, again not because of signal loss per se, but rather the 4-way just won't phase the signals. Use 3 two-ways though and it will work, although not nearly as good as a stripline will.
Depends on what's inside the "common splitter". I'm sure there's all kinds of junk out there.

Here's a very inexpensive non-stripline splitter/combiner with good phase unbalance.

http://minicircuits.com/pdfs/TCP-2-10-75.pdf

Of course, it needs to be put in case with connectors.

Ron

If I were actively fiddling with it at this point I might try it, but I'll probably just leave it as it is for now.:)

Wow. Thats a setup you've got there. I am surprised that as nice as the setup is, that you wired it so haphazardly.

I would have just gotten the chainsaw....

Or raised it a little higher.....

Tough crowd. :)

But it IS an impressive antenna array!

Very impressive array, cpcat! How much gain do you get out of that top arrangement?

Larry
SF

Here's the gain graph for the Triax Unix 100A. It's band specific for uhf 14-38 (UK channels 21-40). The graph on the left is the 100A:
http://alpha.future.ee/triax_unix.png


Theoretically, the gain would approach +6db over that of a single antenna. I'd estimate based on the graph somewhere around 19dbi at channel 14 maybe up to around 22dbi at channel 36. It starts to drop off steeply above channel 40. The horizontal beamwidth is very narrow as you'd expect at around 1/4 that of a single antenna .

Here's the gain graph for the Triax Unix 100A. It's band specific for uhf 14-38 (UK channels 21-40). The graph on the left is the 100A:
http://alpha.future.ee/triax_unix.png


Theoretically, the gain would approach +6db over that of a single antenna. I'd estimate based on the graph somewhere around 19dbi at channel 14 maybe up to around 22dbi at channel 36. It starts to drop off steeply above channel 40. The horizontal beamwidth is very narrow as you'd expect at around 1/4 that of a single antenna .

Yes, they do work well for channels below 40.I have a couple of new Triax Band A's and some Mercury A/E combiners that I can part with if someone needs them.I use four in an inline quad with two widebanders on top for everything above 40.


http://i498.photobucket.com/albums/rr342/locknut-1/Antennas-Dxing/DSC00421.jpg

I am building a house in Melbourne, Florida - unfortunately in a HOA neighborhood that has restrictions on how big the antenna can be. The transmission towers are about 37 miles away (Northwest at 321 degrees).

I want to avoid installing a mast on the roof and instead would like to use a J-mount on the side of my house and aim a compact antenna toward the towers.

Am I deluding myself into thinking that I can get good reception using a compact antenna all the way to 37 miles?

I can't really do attic antenna since my attic is pretty shallow and also because my roof boards have the radiant barrier layer built-in on the inside. This barrier is metal and would prevent an attic antenna from working well.

Any tips!

I am building a house in Melbourne, Florida - unfortunately in a HOA neighborhood that has restrictions on how big the antenna can be. The transmission towers are about 37 miles away (Northwest at 321 degrees).

I want to avoid installing a mast on the roof and instead would like to use a J-mount on the side of my house and aim a compact antenna toward the towers.

Am I deluding myself into thinking that I can get good reception using a compact antenna all the way to 37 miles?

I can't really do attic antenna since my attic is pretty shallow and also because my roof boards have the radiant barrier layer built-in on the inside. This barrier is metal and would prevent an attic antenna from working well.

Any tips!

A compact UHF antenna should do well for all the Orlando stations (except the NBC affiliate WESH) provided you have a decent line of sight towards the towers. WESH will generally require a larger antenna for the high-VHF band. You might want to run and post an accurate TVFool plot for your new home to check for potential specific issues.

FWIW, HOAs under federal law, generally cannot regulate the size or mounting location of OTA antennas to the point that they don't work properly. See the OTARD rules for specifics.

Gotta love those crank down towers.

Looks great!

Yes, they do work well for channels below 40.I have a couple of new Triax Band A's and some Mercury A/E combiners that I can part with if someone needs them.I use four in an inline quad with two widebanders on top for everything above 40.


http://i498.photobucket.com/albums/rr342/locknut-1/Antennas-Dxing/DSC00421.jpg

Gotta love those crank down towers.

Looks great!

Check this out.

http://www.kkn.net/dayton2006/K9LTN.pdf

Ron

Check this out.

http://www.kkn.net/dayton2006/K9LTN.pdf

Ron

Does he get TV from Mars with that thing? Seems A LOT more expensive than just getting cable or satellite. ;)

Does he get TV from Mars with that thing? Seems A LOT more expensive than just getting cable or satellite. ;)

Trust me, this guy wasn't working within a budget. He was building the biggest, baddest, privately owned antenna system ever. Wow.

Somebody in Canada used to make a 32-bay bowtie. 8 vertical by 4 columns. I think it sold for around $4,000 or so, but my link to it expired some time ago.

Trust me, this guy wasn't working within a budget. He was building the biggest, baddest, privately owned antenna system ever. Wow.
It's not known exactly how much it cost. I've seen numbers ranging between $100,000 and $500,000. The list price for each yagi is $2285, so just the six antennas alone cost $13,710.

http://www.steppir.com/Catalog.html

Ron

A compact UHF antenna should do well for all the Orlando stations (except the NBC affiliate WESH) provided you have a decent line of sight towards the towers. WESH will generally require a larger antenna for the high-VHF band. You might want to run and post an accurate TVFool plot for your new home to check for potential specific issues.

FWIW, HOAs under federal law, generally cannot regulate the size or mounting location of OTA antennas to the point that they don't work properly. See the OTARD rules for specifics.

Here is the tvfool report

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3db32b9c97beee6c

I am building a new house and just want to avoid putting a tripod on the roof to support a tall mast and a big antenna. Just a preference. I have use a J-mount before with good success in a different city but the towers were closer. Also, I don't know how well the tripods do in hurricane winds (I assume I need some form of tripod for roof mount).

As you said, most of the DTV channels from Orlando are in UHF except for NBC affiliate. I would like to get all of them. What do you think about the Channel Master 3010 with amplifier?

Urgh...added Channel Master 8 port distribution amp to my setup (to replace 2 splitters - a mess) and lost my distant channels. Too much noise?

Urgh...added Channel Master 8 port distribution amp to my setup (to replace 2 splitters - a mess) and lost my distant channels. Too much noise?

Maybe, but probably not.

More likely it's due to the tuner being desensitized by the now stronger local stations' signals. Might be inter-modulation in the amplifier.

Thanks for the info. I have an attenuator in my line, which may not be enough?
What is inter-modualtion, having signals directly hit the distribution unit?

As you said, most of the DTV channels from Orlando are in UHF except for NBC affiliate. I would like to get all of them. What do you think about the Channel Master 3010 with amplifier?

I predict that the amplifier will be overloaded. You'd be better off with a bit of antenna gain and no amplifier.

Consider this as one antenna that can be mounted on a J pole.
http://www.dennysantennaservice.com/ez_hd_tv_Antenna.html

What is inter-modualtion, having signals directly hit the distribution unit?
http://en.wikipedia.org/wiki/Intermodulation

ugh... so this distribution amp was not worth it at all... yea. $45 bucks shot
It got slightly better when I pulled the attenuator out. But still missising channels and get break up. Cabling is neater and not falling apart :)

I'm having much better luck with the CM3414 distribution amp that I recently purchased to replace my Trunkline 20-TDA25 distribution amp. It has also allowed me to eliminate a splitter and an inter-connect cable.

I need the eight outputs. I cobbled my 2 4-way splitters back together on a wood block. Hopefully more sturdy now. All my channels are back :)

Channel Master has an eight port DA. It's the 3018 (or sometimes known as the CM3018).

Channel Master has an eight port DA. It's the 3018 (or sometimes known as the CM3018).

Now known as the CM3418.

http://www.channelmaster.com/product-overview.php?proID=75&catID=40

Yeah, that's the model I was trying....

Adding a Distribution Amp to a Preamp'd setup is tricky....
You probably need to insert a Variable RF Attenuator PRIOR
to the Distro Amp and then tweak for best performance.

You are trying to find the point at which you have the widest
SFDR (Spurious Free Dynamic Range):
http://www.avsforum.com/avs-vb/showthread.php?p=6163454

Now known as the CM3418.
My mistake. I was actually trying to refer to the 3418.

Adding a Distribution Amp to a Preamp'd setup is tricky....
In my situation, I have about 80 to 100' of coax, two ground blocks, and the PI between the pre-amp and the 3414.

Just picked up a AC 1843 antenna. The thing is a lot bigger than I thought. Is it possible to spray paint everything to make it less of an eye sore or will this effect function? I used to have direcTV and did spray paint the dish with no problems.

Spray away....except where there are electrical connections.
Some spray paint may be better for aluminum than others????

... Is it possible to spray paint everything to make it less of an eye sore or will this effect function?I have spray painted several OTA antennas, with no measurable affect on signal strength or reception.

Hey guys,

I'm in the greater Seattle area, about 20 miles northeast of Seattle proper. I'm trying, and only somewhat succeeding, to get a PBS digital station (KBTC-DT) from Tacoma, which is south of Seattle. They show some programming the Seattle PBS station doesn't. Comcast only carries one of their four channels, and in SD only.

Here's the specific tvfool report for the terrain between me and its transmitter:

http://www.tvfool.com/modeling/?id=b32b9936644f4f&t=ALLTV&n=18

In short, I'm 37 miles and two edges northeast of the 45kW transmitter. Luckily, I'm not hugely below the edges, but it's still not line-of-sight. What you can't easily see there is that I'm on a slope that faces southeast, so at least trees aren't a problem.

Here's the rest of the report, if it's useful:

http://www.tvfool.com/modeling/?id=b32b9936644f4f

Right now, I've got what I think is probably a pretty mediocre 8' directional antenna I got from Radio Shack back in the 90's. I think it's a U-100, but I don't remember. It's fine for Seattle stuff, but this is trickier, with two edges between me and KBTC's transmitter. With the tuner in my S3 TiVo, which seems to be decent, I can get 50-60% at best, but when atmospheric conditions suck (remember, this is Seattle), I can't do better than 30% or so, which isn't enough for a digital lock.

Thus, after doing some research, I have a Winegard HD8200P on its way this week and will be installing it this coming weekend. From what I've read, it should have significantly higher gain in the neighborhood of the channel I'm after, without being overly directional and dropping out the other stations I receive. Given the context, I know I can't expect perfect and consistent reception on the iffy channel, but I'm pretty sure this hardware will improve matters.

So, after all of that, here's the actual question: What sort of amp would get me the best results, given the specific antenna I'm installing, and the fact that I'm mostly trying to get (real) channel 27? The other channels are either present on cable, or ridiculously easy to receive.

The only amp I have on hand is a Channel Plus DA-520A amp that does +20dB (non-adjustable) on 54-1000MHz. I don't know if that's a decent amp, and I don't know if it's at all appropriate for the job. If it is, then great, but if not, I'm quite open to getting something more appropriate.

I should also mention that it'd be nice to get an amp with multiple outputs, since I'm going to be sending the signal to at least two more locations in the house after I do the antenna upgrade. I gather a distribution amp is (often?) better than a single-out amp followed by a splitter.

Anyway, I like to think I'm not an idiot, but OTA is an area I've never done much research on, so I could really use some advice. Even advice not directly responding to my question is quite welcome. Even if it's to tell me I've made all of the wrong assumptions. I do that sometimes. Sigh. :)

Thanks...

I'm curious why you selected the 8200 since you have no low-VHF stations in your area. The 8200 has a lot of excess metal to be hanging in the air when isn't needed.

The Winegard HD8200 has a ton of very long elements designed for LOW-VHF band, which is not being used in your area for DTV. If you can stop the delivery, a Winegard HD7698P would be a much better choice for KBTC.
8200U:
http://i48.tinypic.com/swcnit.jpg

7698P:
http://i48.tinypic.com/2z9cjz6.jpg

The strength of your nearby stations may overload a mast-mounted amp (preamp), which would negatively affect reception of distant stations.

According to the FCC site, KBTC (http://www.fcc.gov/fcc-bin/tvq?list=0&facid=62469) has a construction permit to increase power from 45kW to 100kW. If you're currently receiving it intermittently, the power increase may be enough to gain reliable 24/7 reception for you with existing equipment. Contact the station to see if/when the power increase will be completed.

Or, check your local info & reception thread for possible information on KBTC's upgrade.
http://www.avsforum.com/avs-vb/forumdisplay.php?f=45


.

I agree that the 7698 is a much better choice. If you can't send back the 8200, you will need to address possbile FM issues when you amplify it. I would order the inexpensive HLSJ (http://www.solidsignal.com/pview.asp?mc=03&p=HLSJ&d=Pico-Macom-HLSJ-VHF-Band-HighLow-Antenna-SeparatorCombiner-(HLSJ)&c=Signal%20Splitters&sku=HLSJ) & insert it before the distribution amp. Connect the HI output of the HLSJ to the input of the amp & termiante the LO output.

I'm not familiar with the amp you have now, but I would try it first since you already have it. I personally like the Channel Master 34xx series, because of their high input tolerance.

I agree with Arxaw that a mast mounted pre-amp may overload. Even the highly tolerant HDP-269 would be borderline with the number of local stations you are dealing with. I've only had good results using the HDP-269 with UHF only in strong signal areas. It doesn't tolerate strong VHF well.

The only amp I have on hand is a Channel Plus DA-520A amp that does +20dB (non-adjustable) on 54-1000MHz. I don't know if that's a decent amp, and I don't know if it's at all appropriate for the job. If it is, then great, but if not, I'm quite open to getting something more appropriate.I did a quick look and I couldn't find a Noise Figure (NF) for your DA. I did find the following:


Provides up to 20dB gain to RF signal
Bi-directional capabilities provides compatibility with interactive CATV set-top boxes
54MHz-1GHz forward path and 5MHz-40MHz reverse path
High power, low noise, low distortion and continuous coverage from 40MHz-1GHz
Amplifies all RF bands: VHF, low and high FM and four CATV bands
Includes power supply

First, I'd try using a 4-way or an unbalanced 3-way (-3.5, -7.0, -7.0) by itself. If that doesn't work, I'd look at something with less gain (maybe a CM-3414 - a low output pre-amp may also be a good bet). How long are your cable runs (outlets and antenna)?

You want to try to maintain a low NF and a zero gain output (ie. 10 in, 10 out).

In short, I'm 37 miles and two edges northeast of the 45kW transmitter. Luckily, I'm not hugely below the edges, but it's still not line-of-sight. What you can't easily see there is that I'm on a slope that faces southeast, so at least trees aren't a problem.

Here's the rest of the report, if it's useful:
http://www.tvfool.com/modeling/?id=b32b9936644f4f

Right now, I've got what I think is probably a pretty mediocre 8' directional antenna I got from Radio Shack back in the 90's. I think it's a U-100, but I don't remember. It's fine for Seattle stuff, but this is trickier, with two edges between me and KBTC's transmitter. With the tuner in my S3 TiVo, which seems to be decent, I can get 50-60% at best, but when atmospheric conditions suck (remember, this is Seattle), I can't do better than 30% or so, which isn't enough for a digital lock.

Thus, after doing some research, I have a Winegard HD8200P on its way this week and will be installing it this coming weekend. From what I've read, it should have significantly higher gain in the neighborhood of the channel I'm after, without being overly directional and dropping out the other stations I receive. Given the context, I know I can't expect perfect and consistent reception on the iffy channel, but I'm pretty sure this hardware will improve matters.

So, after all of that, here's the actual question: What sort of amp would get me the best results, given the specific antenna I'm installing, and the fact that I'm mostly trying to get (real) channel 27? The other channels are either present on cable, or ridiculously easy to receive.

The only amp I have on hand is a Channel Plus DA-520A amp that does +20dB (non-adjustable) on 54-1000MHz. I don't know if that's a decent amp, and I don't know if it's at all appropriate for the job. If it is, then great, but if not, I'm quite open to getting something more appropriate.

I should also mention that it'd be nice to get an amp with multiple outputs, since I'm going to be sending the signal to at least two more locations in the house after I do the antenna upgrade. I gather a distribution amp is (often?) better than a single-out amp followed by a splitter.

Anyway, I like to think I'm not an idiot, but OTA is an area I've never done much research on, so I could really use some advice. Even advice not directly responding to my question is quite welcome. Even if it's to tell me I've made all of the wrong assumptions. I do that sometimes. Sigh. :)

Thanks...
The 52 dB stronger Ch25 will make it difficult to receive Ch27. [And that is an ESTIMATE!]
CECB specs (derived from ATSC A/74 "Receiver Recommendations") said that
an undesired Next Adjacent signal should be no more than 44 dB stronger than desired:
http://www.ntia.doc.gov/dtvcoupon/DTVmanufacturers.pdf

Your antenna will need to be steered to suppress Ch25 without causing "too much"
degradation to the already very weak Ch27. The amount of suppression should be
MORE than the 8 dB difference found in non-fading bench tests....say 20 dB total
to continue protection when the weaker signal undergoes multipath fading....
This will be VERY DIFFICULT to do, just using an antenna....

You have several very strong local stations that can generate intermod noise on top of
weak stations when they pass through a Preamp, Distribution Amp...or even your Tuner.
A Preamp (even the high overload W-G HDP-269) may or may not help....probably not...
You could try a low gain Distro Amp (with a Variable RF Attenuator) to see if it helps or hurts....
You might get lucky.....or Murphy's Law will prevail.....

After trying all of the above, you might consider a separate antenna aimed at Ch27, with
the signal passed through a Single Channel Bandpass Filter (or less precise Ch27 JoinTenna)
before going through a low-gain Preamp (HDP-269) or even that Distro Amp prior to being
combined into the downlead coax.....this suppresses Ch25 prior to going through the Ch27 amp.

All things being equal, there is NO DIFFERENCE between a Distro Amp with an INTERNAL splitter
and a separate Preamp/Amp with an EXTERNAL splitter. Of course a Distro Amp with unknown
(or unbelievable) Noise Figure specs may not be "equal".....
And of course a 2-way splitter has 4 dB less loss than a 4-way splitter....

Linear Corp (manufacturer) website doesn't have NF specs or a manual for the 20 dB Gain DA-520A:
http://www.linearcorp.com/audio_video_distribution.php#amplifiers

However, they do cite 5.5 dB NF in the Manual for the very similar 18 dB Gain DA-500A:
http://www.linearcorp.com/pdf/manuals/DA-500A.pdf
Both of these amps are two-way capable for CABLE applications, optimized for a large number of
very strong signals.....and not optimized for wide dynamic range OTA TV.

BTW: These are HIGH GAIN amps and hence will be INCOMPATIBLE with strong input signals
due to generation of intermod noise products all across the weak signals.....

Your antenna will need to be steered to suppress Ch25 without causing "too much" degradation to the already very weak Ch27. The amount of suppression should be MORE than the 8 dB difference found in non-fading bench tests....say 20 dB total to continue protection when the weaker signal undergoes multipath fading...This will be VERY DIFFICULT to do, just using an antenna....


Here's how to do it. http://www.hdtvprimer.com/ANTENNAS/ganging.html

Use two identical UHF antennas, stack them 31" apart. (22 degrees channel 26) Feed them in phase.

Wow, lots of feedback. I think I'll roll all of my responses into one post:

-----

I'm curious why you selected the 8200 since you have no low-VHF stations in your area. The 8200 has a lot of excess metal to be hanging in the air when isn't needed.

Mainly because information overload got in the way, apparently. It's pretty hard to come at this stuff from a position of near-zero knowledge. I mainly looked for something that, at least according to mathematical models, got the best reception across the entire range. It didn't occur to me to see if I actually needed the whole range, alas.

Given the other responses, I'm thinking I should have done something I absolutely hate other people doing, which would have been to come here and say, "I know nothing, someone tell me what to do!" :rolleyes: Oh, well.

-----

The Winegard HD8200 has a ton of very long elements designed for LOW-VHF band, which is not being used in your area for DTV. If you can stop the delivery, a Winegard HD7698P would be a much better choice for KBTC.
Nope. I don't have the option to stop delivery at this point.

I obviously haven't had the opportunity to assemble one yet, but unless I'm crazy, it sure looks to me like the 8200 is just be a 7698 with extra stuff bolted on the back half. If so, perhaps I could get away without the extra elements...? I might need a counterweight of some sort, since it'll throw off the center of mass, but looking at the two images, the pivot point seems to be in the same place, so maybe not.

I got a reasonably good price on the 8200, so if I need to discard part of it, it's not a huge loss.

-----

I agree that the 7698 is a much better choice. If you can't send back the 8200, you will need to address possbile FM issues when you amplify it. I would order the inexpensive HLSJ (http://www.solidsignal.com/pview.asp?mc=03&p=HLSJ&d=Pico-Macom-HLSJ-VHF-Band-HighLow-Antenna-SeparatorCombiner-(HLSJ)&c=Signal%20Splitters&sku=HLSJ) & insert it before the distribution amp. Connect the HI output of the HLSJ to the input of the amp & termiante the LO output.

Good idea. I'll do that.

-----

First, I'd try using a 4-way or an unbalanced 3-way (-3.5, -7.0, -7.0) by itself. If that doesn't work, I'd look at something with less gain (maybe a CM-3414 - a low output pre-amp may also be a good bet). How long are your cable runs (outlets and antenna)?

I suppose once I get a better antenna, I might not need amplification, so that's a good point.

The cable run I have right now is about 40', I think. Measuring right now isn't an easy option, so I'm going to have to leave it as a guesstimate. The additional runs will be similar.

-----

After trying all of the above, you might consider a separate antenna aimed at Ch27, with the signal passed through a Single Channel Bandpass Filter (or less precise Ch27 JoinTenna) before going through a low-gain Preamp (HDP-269) or even that Distro Amp prior to being combined into the downlead coax.....this suppresses Ch25 prior to going through the Ch27 amp.

That's an option. As mentioned, I will still have the original RS antenna on hand, and it's more than adequate for the other locals. I have no problem with using the new antenna for just 27.

All things being equal, there is NO DIFFERENCE between a Distro Amp with an INTERNAL splitter
and a separate Preamp/Amp with an EXTERNAL splitter.

I was just thinking in terms of needing fewer connections along the path. I don't know about OTA, but I assume it's similar to cable tv, wherein I find the signal rapidly degrades when you have a lot of extra cruft along the line.

BTW: These are HIGH GAIN amps and hence will be INCOMPATIBLE with strong input signals
due to generation of intermod noise products all across the weak signals.....

Yeah, I had a feeling the gain was too high on the one I have.

-----

Here's how to do it. http://www.hdtvprimer.com/ANTENNAS/ganging.html

Use two identical UHF antennas, stack them 31" apart. (22 degrees channel 26) Feed them in phase.

Ooo, that's cool voodoo. I've seen arrangements like that before and not understood why they were the way they were. Makes more sense now. Given the apparently-coming increase in transmitter power, I hope I won't need to do this, but it's pretty cool to know it can be done.

-----

Thanks to all for the information. It's not falling on deaf ears. Very useful. I'm going to be a numbskull for a while yet, but this was a good first day at school. :)

...I obviously haven't had the opportunity to assemble one yet, but unless I'm crazy, it sure looks to me like the 8200 is just be a 7698 with extra stuff bolted on the back half. In terms of gain for the channels being used in your area, they are about the same. I don't think it would be a good idea to modify it, but others with much more knowledge about such things will hopefully offer their thoughts on doing that.

Antennas that cover Lo-VHF and Hi-VHF are computer designed as a SYSTEM.
Hacking off the larger elements could result in huge Gain and/or SWR holes in the response.

Antennas that cover Lo-VHF and Hi-VHF are computer designed as a SYSTEM.
Hacking off the larger elements could result in huge Gain and/or SWR holes in the response.

Don't get me wrong. I didn't mean I'd hack off the elements. I mean the 8200 literally looks like a 7698 with an extra segment attached above the back end, upon which the long elements are attached.

If you look at the two images and disregard the fact that they're drawn with different line weights, it looks to me like every single part of the 7698 is present on the 8200, in exactly the same configuration. I think the 8200 really *is* a 7698 with another section tacked on the top, behind the folding portion. It sort of makes sense as a concept, because it'd cut down on manufacturing costs for Winegard.

But, no, if it's all one thing and not just a 7698 with an extra part, I certainly won't be cutting bits off of it. I'll either have to filter out low VHF or find someone who wants to buy it so I can get the 7698.

Okay, I went out and found some higher-resolution photos of the two antennae. I can see now that the differences in the back end are integral, not bolted on as I thought I was seeing.

Filter or sell, then.

II would order the inexpensive HLSJ (http://www.solidsignal.com/pview.asp?mc=03&p=HLSJ&d=Pico-Macom-HLSJ-VHF-Band-HighLow-Antenna-SeparatorCombiner-(HLSJ)&c=Signal%20Splitters&sku=HLSJ) & insert it before the distribution amp. Connect the HI output of the HLSJ to the input of the amp & termiante the LO output.
Question: Do I need to split UHF out before the HLSJ and then combine it back in after? Or does the HLSJ pass UHF unmolested?

Edit: presumably using two UVSJ's (http://www.solidsignal.com/pview.asp?p=UVSJ&mc=03).

...does the HLSJ pass UHF unmolestedNot sure about all HLSJs, but Pico-Macom (http://www.techcab.com/proddetail.php?prod=HLSJ) HLSJs do not attenuate any of the UHF frequencies in the US DTV band.

For a 8200, you'd probably want to just use the HLSJ. If you didn't need the UHF, then a UVSJ would be appropriate (terminate the UHF side).

Well, on the bright side, even with the issues already raised, there is apparently such a quality difference between my old Radio Shack model and the HD8200P (gee, big surprise) that I went straight from a 51% signal to a pretty solid 70% signal just by swapping the cable over from the old to the new. I made absolutely no other change, since the HLSJ is not here yet. Not bad. :)

It remains to be seen what will happen when atmospheric conditions turn to what gave me a 20-30% signal on the old antenna, but I'm at least a little hopeful. Perhaps I can at least survive more borderline conditions. I seem to need >50% for a decent stream. With the additional changes that are yet to come, and better than just a quick eyeball aiming, I hope for better still.

Oh, and it's funny... I ran into every single issue I've ever seen mentioned about the 8200:

- box arrived with all of the staples broken open
- poor packing (or lack thereof) resulted in several bent elements
- some of the instructions were pretty unclear
- had to cut some flash off of the bolt hole at the join between front and back

Some of you may be interested in this. I do not work for Ace Hardware, but it is a good deal.

The CM 1630 30' telescopic mast is $99 and change, and they will ship it to the nearest Ace Hardware store for free.

So if you've been looking for one but amazed at the $140 freight charge, now is a good time to get one at a reasonable price.

They do not carry the 1640 that I could find.

I ordered my 1630 today, hopefully it will show up in the next week or 2.

Also, you will have to buy guy lines, turn-buckles, etc. Figure 100' of guy line per side. So 300' for a 3 line and 400' for a 4 line setup. That would cover either 20 or 22' radius from the base. And then you'll need some 3' or 4' screw anchors and a base plate.

Now for those of you that know zoning, would this be considered a temporary antenna support structure / structure ? And what is the square footage? Is it just the square foot measurement of the base, or do you need to factor in the entire radius of the guy wires? If a structure is 100 sf or less, no permit is needed here :-).

~ryan

Some additional info re Stacking Antennas:
http://www.digitalhome.ca/forum/showthread.php?p=963113

Does anyone have any experience with a TB-105 alignment bearing with a Channel Master 9521A rotator? I am having trouble getting them to line up correctly with a 1 1/4" mast or a 2" mast. Any ideas of what could be going wrong. The mast seems to be 1/4" to 1/8" to close to the mast side of the bearing.

I entered tb-105 in google search box at top of page. Here are two of many that came up:

http://www.avsforum.com/avs-vb/showpost.php?p=7971691&postcount=319
http://www.avsforum.com/avs-vb/showthread.php?t=546066&page=44 posts 1314 & 1315

I entered tb-105 in google search box at top of page. Here are two of many that came up:

http://www.avsforum.com/avs-vb/showpost.php?p=7971691&postcount=319
http://www.avsforum.com/avs-vb/showthread.php?t=546066&page=44 posts 1314 & 1315

That might explain why my CM rotator burnt up after a month or so after installing the TB105 and having 6' of mast above the bearing.

I just used the strong arm rotator and a pipe wrench from the base of the mast I built from Home Depot..

Just moved to a new place, so I'll have to wait for the ground to thaw before putting up the new CM1630 mast. I'll test fit the new rotator and old TB105 and make sure there is no binding this time :-). No beer on this install :-) might help with alignments.

~ryan

Click on the picture link inside of this post to see how I am using a TB-105 and 9521A together. I'm not sure about the diameter of the mast, but I probably got it at Radio Shack.

http://www.avsforum.com/avs-vb/showthread.php?p=14275194&highlight=#post14275194

It's been up about 5 years and so far no problems.

Thanks guys. With the abundance of knowledge I have recieved here I think I got figured out. I will try it this weekend. Thanks all.

Here are pictures of my homemade Dry Bearing setup: http://www.avsforum.com/avs-vb/showthread.php?p=15946674#post15946674

Detail information discussion starts on this page:
http://www.avsforum.com/avs-vb/showthread.php?t=381623&page=289

Does anyone have any experience with a TB-105 alignment bearing with a Channel Master 9521A rotator?The center point of rotation of the TB-105 does not match the center point of rotation of the CM-9521. The TB-105 center point of rotation is further away from the mast than the CM-9521. It may be possible to put a spacer between the mast and the CM-9521 to bring them into alignment.

I still haven’t gotten around to:
For a bearing to work correctly its center point of rotation must match that of the rotor. One of these days I am going measure the mount dimension and the mount-to-bearing dimension on the rotor, draw it up in CAD and take the bearing to a metal milling shop and have them cut the bearing to match the CM rotor.

Hello,

I'm trying to identify the antenna that the previous owners of my Mom's house have mounted there.

http://img34.imageshack.us/img34/7634/antennad.jpg

It's about 30 feet up, so I'm hesitant to climb up there and check it out, and I'm wondering if anybody can ID it for me. I'd like to hook up her HDTV with an ATSC tuner to it to get OTA HD, but I'm wondering what I'd be dealing with. I'm thinking about getting someone with a bucket truck or a safety harness and lanyard to hook it up, but I'd like to know what I'd need before I get them out here. She lives in Kentucky on the Tennessee border, and she's close enough to Knoxville that I can pick up a couple of stations with an indoor antenna, so I'm sure she could get them all if she hooks up that beast. Any help you could offer with suggested setups would be appreciated as well. (will she need a signal booster? what should she do since the area she's in is prone to lightning strikes? etc.)

Thanks in advance.

The Parabolic "Dish-Type" antenna appears to be the old, UHF-only Channel Master CM4251:
http://www.rocketroberts.com/cm4251/cm4251.htm

Below it, pointed in the OPPOSITE direction is an old VHF-only antenna I can't identify.
Note that the front (shortest) element is slightly bent and appears to be missing half of
element "rear-ward" by 5 elements.
This will degrade performance, but probably not by very much....

If the downlead is as old as the antennas, it needs to be replaced with coax.
There appears to be some "black boxes" [in front of???] the dish's reflector.
Whatever antenna combiners and/or Preamps "black boxes" will definitely
need to be replaced if they are more than say 5 years old.

We don't know anything about your signal levels until you enter your location into www.tvfool.com
and when results are displayed, copy/paste the URL (web address at top of browser) so
we can see it [since you haven't posted min # of posts to post a URL, just post what follows .com.

Thanks for the help.

I've been to TVFool and I got this report.

/?option=com_wrapper&Itemid=29&q=id%3d9fbe2dca121b98

She's already getting the two "green" stations.

Edit: Check that, she's getting channels 14 and 20. The Channel Master is pointed North at the moment, which wouldn't be the correct direction to pick up Knoxville stations. Based on what I've read I guess it has a rotator, and I'd also assume that the motor and controls would be junk at this point. Based on that report I guess my best bet is to point it at 150 degrees and just leave it?

Thanks again for the assistance.

DASven,

Welcome to the forum. Her tvfool report should look like this:
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d9fbe2dca121b98

And a map is in the attachment:

DASven, the Channel Master 4251 parabolic is a very good UHF antenna. I helped a friend install a 4251 along with a large Channel Master VHF antenna on a 48 ft. tower about 45 miles north of Indy in 1975. The original VHF antenna and preamp were replaced in 1985, while the 4251 is still on the tower and providing DTV stations from South Bend @ 81 miles and Fort Wayne @ 66 miles. It's been out in the weather (snow, ice, ice storms, etc.) for 35-years and is still going strong. In fact, he just had a new preamp and new coaxial cable installed a few days ago. Of course, when we installed in 1975 I never dreamed it would still be usable 35-years later. I no longer live in that area, but I used to have the little brother version, a 6-ft. model (4250) instead of the 7-ft. model.

For more background info on this well-known UHF antenna, check out this tribute site. http://www.rocketroberts.com/cm4251/cm4251.htm

You might need to hire an antenna/tower installer to check it out and see if you need a new preamp, rotator, coaxial cable and to make sure the antennas are in good working order. Best wishes in getting it back to pulling in some great signals.

Steve

It's kind of a surprise when you find out that the antenna you've got is probably one of the most powerful available. It really doesn't look like it's got a 7 foot diameter from the ground, but by eyeballing it against the tower I guess it does. Apparently she's already outright told two people that they can have her antenna setup if the want to come get it. Luckily no one has taken her up on the offer. Right now she pays an extra $15 a month to DirecTV for the network stations, and she could save that and get a lot better picture if she just hooks up her antenna.

Thanks for the info everyone.

Pointing both UHF and VHF antennas toward 150-deg (wrt True North) should be
good for Ch20 (CW), Ch10 (NBC), Ch23 (ION), Ch26 (ABC) and Ch34 (FOX) and
CH7 (Ind WMAK) might also be received.

However, your nearest CBS station, WYMT on Ch12, will be on the sidelobe of the
VHF antenna, with considerable gain loss, so it might not come in without a rotator.
Fortunately, there's a weak CBS station, WVLT on Ch30, that might come in on the
UHF antenna, especially if you're using a modern Preamp, like the CM7777.

Your closest PBS station on Ch14 is on the backlobe of the UHF antenna, but the
Front/Back Ratio on the CM4251 isn't all that high, so it stands a good chance of
also coming in without the pain of rotating the antenna.....Maybe....YMMV....

=============================================
DirecTV website says Local Channels are included in price of their various packages.
The $15/mo charge doesn't sound right......and 1-2 years ago it was only $5/mo.

It's kind of a surprise when you find out that the antenna you've got is probably one of the most powerful available. It really doesn't look like it's got a 7 foot diameter from the ground, but by eyeballing it against the tower I guess it does. Apparently she's already outright told two people that they can have her antenna setup if the want to come get it. Luckily no one has taken her up on the offer. Right now she pays an extra $15 a month to DirecTV for the network stations, and she could save that and get a lot better picture if she just hooks up her antenna.

Thanks for the info everyone.



If she has D* DNS feeds then that's pretty good PQ. Don't convince her to get rid of them or she'll never get them back. I think you are mistaken in the amount she "pays extra" for them. Mine are free and I suspect hers are as well.

OTA from that location will likely be better towards Knoxville like others have said, but it really depends on the terrain. If the UHF antenna was previously pointing north there may have been a good reason.:) WDKY 31 FOX from Clay's Ferry may be pretty strong, it certainly is here. The other Lexington stations are very difficult (at least from my location in Corbin). WKYT CBS 13 is soon switching to 36 but no one knows how good the signal will be yet. To the Northwest you might be surprised to pick up some Louisville signals but I doubt they'd be strong enough to be consistent.

The problem to the south is the Cumberland Plateau. Certainly, Knoxville is closer but if you are obstructed then you won't have much luck. You might give it a whirl in more or less the original position. You may get the Lexington UHF's and VHF 10 WBIR from Knoxville at that position. You won't get the VHF 7 from Knoxville as its signal is very weak to the north due to the VHF 7 in Beattyville.

There is alot of terrain b/w you and Hazard, but WYMT might be worth a try especially since you already have a nice VHF wide bander up there. Don't forget WKYT 13 though.

Thanks for all the great input.

About the $15 charge for the network stations. She gets East and West coast feeds of ABC, CBS, NBC, and FOX. I've seen her bill, and I'm pretty sure (but not positive) it is an extra $15 she is paying for them. There is an extra charge for the stations though.

Thanks for all the great input.

About the $15 charge for the network stations. She gets East and West coast feeds of ABC, CBS, NBC, and FOX. I've seen her bill, and I'm pretty sure (but not positive) it is an extra $15 she is paying for them. There is an extra charge for the stations though.

Depending on the package you have, locals are $5 per month. Extra boxes, beyond the 1st one, are another $5 per month. How many boxes are used?

Depending on the package you have, locals are $5 per month. Extra boxes, beyond the 1st one, are another $5 per month. How many boxes are used?

He's talking about the distant stations from New York and LA.

DASven; There are plenty of forum members (and others) that would kill to have that antenna on their house. ;)

I didn't see either one of these listed that apparently came out over a year ago;
http://www.amazon.com/Outdoor-Antenna-Remote-Controlled-HD-2805/dp/B002MVRCSI
http://www.lavasat.com/product_detail.php?proid=57

that replaeced this model;
http://www.amazon.com/Digital-outdoor-antenna-control-HD-2605/dp/B002MW0K22/ref=sr_1_1?ie=UTF8&s=electronics&qid=1275658983&sr=1-1

Or this no-name (not that the above is a "name" product). Item #250461703389;
http://cgi.ebay.com/DTV-HD-TV-Outdoor-Rotating-Digital-Antenna-Kit-Remote_W0QQitemZ250461703389QQcategoryZ149955QQcmdZViewItemQ Q_trksidZp4340.m8QQ_trkparmsZalgo%3DMW%26its%3DC%26itu%3DUCC %26otn%3D20%26ps%3D63%26clkid%3D8057677527265216921

They appear to be a combination UHF antenna, preamp and rotor in one. Doing a little search, the PS seems to be a issue.

I'm torn between using a rotator setup or dual fixed antennas with a combiner, one pointing the same direction as my current antenna and the other about 90 degrees in another direction. My current antenna is 177" long VHF/UHF (9000) with about 40 ft. of RG-6. Then again maybe use two antennas aimed in the same direction with the rotator. Is this all a waste of time or can there be a substantial signal gain using the two antennas.

can there be a substantial signal gain using the two antennas.The best one can achieve is a 2.5 db gain 'stacking' antennas if everything is done correctly. AFAIC, it really isn't worth it. Moving and/or raising an existing antenna would probably give you more.

I'm torn between using a rotator setup or dual fixed antennas with a combiner, one pointing the same direction as my current antenna and the other about 90 degrees in another direction.

A rotor on your present antenna will solve your problems, unless you have a DVR. With a DVR, you need to have all of your stations available, if you can, so you don't have to worry about having the antenna pointed in the right direction.

I've tried using two antennas with a combiner and the results have been mixed. You lose signal in the combiner, so the weaker signals might be lost or on the edge. That was my problem for stations that are 35 or more miles away. Sometimes they'd come in, sometimes they wouldn't, depending on the atmospheric conditions.

I ended up with an antenna on a rotor so that I could get all of the stations, but also left the two other combined antennas up there. I use an A-B switch to select between the two. I leave the two combined antennas connected to the DVR, but have the option of switching to the other antenna with the rotor if need be to pick up stations the combined antennas don't get.

I didn't answer your question, but gave you some food for thought. :)

Larry
SF

Thanks for your answers. I will go the rotator route as you have enlightened me on the combiner thing. The 2.5 db double antenna gain and 3 db loss through the combiner seems like a waste of time unless there is some space diversity envolved.
JJK

I've been using stacked UHF antennas for several years in receiving weak DTV stations for DXing purposes. I have two Triax Unix 100 wideband UHF antennas horizontally stacked (40.5 inches apart) @ 42 ft. AGL. Now I'm testing two Triax Unix 100 A-band antennas. These antennas are designed for channels 14 - 38 with a little more gain and are about two feet longer than the wideband antennas. I also have a single Antennas Direct 91XG (very similar design to the Triax wideband antennas) mounted just below the stacked antennas @ 40 ft. AGL.

Some fairly strong tropospheric enhancement in this area this morning gave me an opportunity to compare reception abilities between the new Triax A-band stack and the single 91XG. Using identical receivers (Insignia NS-DXA1) I caught some screenshots from various stations and here a few of them: WEWS-DT (15) and WUAB-DT (28), Cleveland, OH @ 253 miles; WSBT-DT (22), South Bend, IN @ 116 miles. Pictures 1, 3 and 5 are with the Triax stack and pics 2, 4 and 6 are with the single 91XG. Nothing scientific, but this is what I've seen most of the time over the years since I started using a stack. BTW, the two Triax antennas are joined via coaxial cable through a 2-way splitter in reverse. A few stations did and will decode easier with the single antenna, but my results indicate this is not a common occurrence among most.

Pics 5 and 6 of WSBT in next post due to maximum download size.

Continuation post....Part two with pics 5 and 6.

Steve

Very interesting.
JJK

The best one can achieve is a 2.5 db gain 'stacking' antennas if everything is done correctly. AFAIC, it really isn't worth it. Moving and/or raising an existing antenna would probably give you more.

Except if you're like me and you can't raise any higher. My antennas are already at 70ft. I am almost 50 miles out from NYC and the path here is 2 edge diffraction.

TV Fool (http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3db7c86cef718c65)

I have a two stack of CM4228A (old style, not 4228HD) which performs much better than one by itself. I use twin lead for phasing and a SD3700 as the combiner. Works very well.