HR20 and OTA: Copper clad vs. solid conductor

[baesterling]

I am having some problems with audio dropout and pixelization using OTA on HD locals, however, I am getting nearly or at 100% signal strength on the HR20 for all channels (which come from the same tower--about 27 miles away). I have tried a number of things including adding a distribution amp, running the most recent CE software, adding a splitter (at Winegard's suggestion) and replaced all connectors with Digicon. The cable is RG6. However, I just noticed that some of the cables along the path between the antenna and HR20 are solid copper conductor and some are copper clad. The total cable length is about 150 feet. Do you guys have any suggestions? Should I use solid copper conductor througout? Does it matter? Is one better than the other for OTA?

[Tom Robertson]

I am having some problems with audio dropout and pixelization using OTA on HD locals, however, I am getting nearly or at 100% signal strength on the HR20 for all channels (which come from the same tower--about 27 miles away). I have tried a number of things including adding a distribution amp, running the most recent CE software, adding a splitter (at Winegard's suggestion) and replaced all connectors with Digicon. The cable is RG6. However, I just noticed that some of the cables along the path between the antenna and HR20 are solid copper conductor and some are copper clad. The total cable length is about 150 feet. Do you guys have any suggestions? Should I use solid copper conductor througout? Does it matter? Is one better than the other for OTA?

For OTA, without an amplifier at the antenna, Copper over steel and solid copper will perform nearly identically. The signal is carried by the skin of the conductor, unlike DC which would be carried via the whole conductor. I don't think that is your problem.

More likely would things like planes flying in the path between you and the towers (had that in CA) or multipath distortion (the digital equivalent of ghosts from the analogue TV days) or other interference. Perhaps a strong FM transmitter nearby?

How often and how long does the pixelization occur? That can be a big clue to what you're looking for.

Cheers,
Tom

[hasan]

I am having some problems with audio dropout and pixelization using OTA on HD locals, however, I am getting nearly or at 100% signal strength on the HR20 for all channels (which come from the same tower--about 27 miles away). I have tried a number of things including adding a distribution amp, running the most recent CE software, adding a splitter (at Winegard's suggestion) and replaced all connectors with Digicon. The cable is RG6. However, I just noticed that some of the cables along the path between the antenna and HR20 are solid copper conductor and some are copper clad. The total cable length is about 150 feet. Do you guys have any suggestions? Should I use solid copper conductor througout? Does it matter? Is one better than the other for OTA?

What kind of antenna are you using? It sounds like you may be getting a lot of multi-path, which the HR20 may not handle very well. In that case, you need a more directive antenna, in addition to the info below:

The only thing (with your current setup) that the RG6 copper clad is being used for is RF. There is no significant difference in RF loss between copper clad and solid copper.

150 feet of RG/6 has a LOT of loss. It calculates out at 8.4 dB....that is nearly a reduction of 90%....around 90% of your signal is disappearing BEFORE it gets to the tuner. The distribution amp after all that loss is doing next to nothing. Take it out.

I'm 27 miles from our transmitting complex and their antenna height is 2200 feet. I have a medium sized vhf/uhf antenna and 40' of feedline. If I had over 8 dB of coax loss like you do, I would do one of two things:

1. Replace the RG-6 with much lower loss half-inch cable from the LMR series (that would cost at least 60 cents per foot, plus connectors...you'd have well over a hundred bucks in it. (Bad choice)

2. Put an antenna mounted preamp like the Channel Master 7777 out at the antenna (power for it comes up through the RG/6 coax. (Good choice) I think that preamp is less than 60 bucks from Solid Signal.

A proper layout for your setup would look like this:

Antenna > Short Jumper > Antenna Mounted Preamp > 150' RG/6 > Passive Splitter (2 or 3 to 1, depending on your needs)

The "short jumper" referred to above goes from the antenna terminals to the input of the mast mounted preamp...no more than 5 feet or so.

This setup wipes out nearly all the loss of the 150' of cable following it, and for very low cost, plus provides plenty of signal to run multiple TVs, should you need it. The other thing I would do (if needed) is get a variable attenuator, 75 ohm variety (google Variable Attenuator TV). They are less than 10 bucks and will come in handy.

Place the attenuator right at the input of the HR20 and use it to optimize the signal level coming into the HR20. It is VERY easy to overdrive the HR20. It is very easy to not provide enough signal to the HR20...the trick is getting it in the "optimum level" area.


My setup looks like this:


Antenna > 40' RG-6 > Mast Mounted preamp used as distro amp in the house > Variable Attenuator > Splitters.

Note this is NOT the typical use of an antenna mounted/mast mounted preamp. I'm taking advantage of its low-noise and high intermod rejection to use it as a distribution amp in the house. Typical distribution amps have very poor noise figures (the measure of sensitivity), but plenty of gain. This is not very helpful. All the gain does is amplify the noise, so having a low noise figure is ESSENTIAL.

All your cable losses ahead of any RF amplifier (TV front end or distro amp), add directly to the noise figure of your HR20 tuner, making it's sensitivity VERY POOR. Your current system noise figure is abysmal:

8 dB coax loss + 4 dB (or worse) distro amp = 12 dB in front of the HR20. I can't describe to you how terrible this is. Your system noise figure should be no worse than 3 dB for good performance. Notice we aren't talking about "gain"...forget gain...it's virtually meaningless. As long as your low noise preamp has at least 10 to 15 dB of gain (and they all do), and no more than 20 to 25 (lower is better in this range), it will do its job fine. Gain is the big liar as far as amps go...NOISE FIGURE IS EVERYTHING!

So...get the mast mounted preamp, put it out where it belongs and then just fiddle with the amount of input signal your HR20 is seeing and you should do fine....IF you aren't having lots of multi-path issues caused by a low gain (small) antenna and terrain that reflects a lot of signals. (large obstructions like buildings, sharp hills (as opposed to rolling pasture), water towers, etc...close to you and in between you and the transmitter site (same direction, or in line behind you from the transmitter direction).

I would call solid signal and ask them (after you tell them where you are and how far you are from the transmitter site), what kind of antenna they would recommend, along withe the CM 7777 preamp.

[veryoldschool]

You left out the power inserted for the pre-amp. :lol:
BTW: very much like my system too...

[baesterling]

Well, I am using a Winegard SS2000 that has a pre-amp built in. That pre-amp has a 12db gain. When I called Winegard, they felt that a distribution amp placed after the pre-amp may be overkill and actually recommended a splitter at the TV. I have done both. Actually, from my brief test trials, it does seem that I have more problems with the distribution amp connected. The sound loss and pixelization appear to be fairly random, but I experience them on all HD locals. Some shows will be just fine, and others will have intermittend sound loss and pixelization. It rarely lasts more than a moment, but sometimes those moments are back to back, with sound coming in and out. The problem seems to be much more with audio dropouts than video pixelization.

I believe with the SS2000, it is directional and I am pointed in the right direction. There are no trees, hills, etc. blocking the antenna and the sky in the direction that it is pointed.

Would it help to put the distribution amp near the antenna? I tried that momentarily, but did experience the sound dropout.

Without the distribution amp, I think I have the setup you are recommending:

antenna with pre-amp>power inserter>150 feet RG6>splitter>HR20

Probably the only thing I have not tried is the variable attenuator. This may be consistant with what Winegard was saying when they said they were worried I was getting too much signal.

Any other thoughts? I really appreciate the input.

[baesterling]

BTW, is there univeral agreement that solid copper vs copper clad does not make a difference? Solid Signal recommended solid copper and of course the RG6 that was installed during house construction is copper clad...

[Tom Robertson]

BTW, is there univeral agreement that solid copper vs copper clad does not make a difference? Solid Signal recommended solid copper and of course the RG6 that was installed during house construction is copper clad...

For OTA, copper clad is normally fine. High frequency doesn't need the whole conductor, just the skin of the conductor.

But, for the satellite signals, because the receiver supplies power to the dish as a DC current, DC needs that whole conductor to be copper for longer runs. Otherwise the power to reach the dish isn't enough to energize the LNBs and/or reliably tell the LNB which polarity to send down the coax.

Even then, for short runs between the dish and the receiver, copper clad steel will work.

Cheers,
Tom

[veryoldschool]

BTW, is there univeral agreement that solid copper vs copper clad does not make a difference? Solid Signal recommended solid copper and of course the RG6 that was installed during house construction is copper clad...
Copper is better. A B-2 is better than a B-17, both will drop a bomb on you. Do you need to have it done my a B-2? The bomb is the same.
Too much Gain [as with amps] will amplify the noise floor too [not good]. What is best" have the signal the highest & the noise the lowest. Big antenna, pre-amp close, this way the signal is the highest & the noise the lowest. Do you have any FM towers in the area? They have proven to be of some trouble [adding to the noise].
Are there any planes that are flying around your area? They can cause short dropouts as they either block or reflect the signal.
Hasan's attenuator might do some good if the signal is too strong to the HR-20 as it doesn't have the best tuner for all conditions.

[baesterling]

Copper is better. A B-2 is better than a B-17, both will drop a bomb on you. Do you need to have it done my a B-2? The bomb is the same.
Too much Gain [as with amps] will amplify the noise floor too [not good]. What is best" have the signal the highest & the noise the lowest. Big antenna, pre-amp close, this way the signal is the highest & the noise the lowest. Do you have any FM towers in the area? They have proven to be of some trouble [adding to the noise].
Are there any planes that are flying around your area? They can cause short dropouts as they either block or reflect the signal.
Hasan's attenuator might do some good if the signal is too strong to the HR-20 as it doesn't have the best tuner for all conditions.

There are planes occasionally as we live about 20 miles from the airport (in about the same direction as the towers). I think the signal is pretty strong as it is 100% on all locals (except for Fox which is 95-98%). I think I will give this a try.

[baesterling]

What kind of antenna are you using? It sounds like you may be getting a lot of multi-path, which the HR20 may not handle very well. In that case, you need a more directive antenna, in addition to the info below:

The only thing (with your current setup) that the RG6 copper clad is being used for is RF. There is no significant difference in RF loss between copper clad and solid copper.

150 feet of RG/6 has a LOT of loss. It calculates out at 8.4 dB....that is nearly a reduction of 90%....around 90% of your signal is disappearing BEFORE it gets to the tuner. The distribution amp after all that loss is doing next to nothing. Take it out.

I'm 27 miles from our transmitting complex and their antenna height is 2200 feet. I have a medium sized vhf/uhf antenna and 40' of feedline. If I had over 8 dB of coax loss like you do, I would do one of two things:

1. Replace the RG-6 with much lower loss half-inch cable from the LMR series (that would cost at least 60 cents per foot, plus connectors...you'd have well over a hundred bucks in it. (Bad choice)

2. Put an antenna mounted preamp like the Channel Master 7777 out at the antenna (power for it comes up through the RG/6 coax. (Good choice) I think that preamp is less than 60 bucks from Solid Signal.

A proper layout for your setup would look like this:

Antenna > Short Jumper > Antenna Mounted Preamp > 150' RG/6 > Passive Splitter (2 or 3 to 1, depending on your needs)

The "short jumper" referred to above goes from the antenna terminals to the input of the mast mounted preamp...no more than 5 feet or so.

This setup wipes out nearly all the loss of the 150' of cable following it, and for very low cost, plus provides plenty of signal to run multiple TVs, should you need it. The other thing I would do (if needed) is get a variable attenuator, 75 ohm variety (google Variable Attenuator TV). They are less than 10 bucks and will come in handy.

Place the attenuator right at the input of the HR20 and use it to optimize the signal level coming into the HR20. It is VERY easy to overdrive the HR20. It is very easy to not provide enough signal to the HR20...the trick is getting it in the "optimum level" area.


My setup looks like this:


Antenna > 40' RG-6 > Mast Mounted preamp used as distro amp in the house > Variable Attenuator > Splitters.

Note this is NOT the typical use of an antenna mounted/mast mounted preamp. I'm taking advantage of its low-noise and high intermod rejection to use it as a distribution amp in the house. Typical distribution amps have very poor noise figures (the measure of sensitivity), but plenty of gain. This is not very helpful. All the gain does is amplify the noise, so having a low noise figure is ESSENTIAL.

All your cable losses ahead of any RF amplifier (TV front end or distro amp), add directly to the noise figure of your HR20 tuner, making it's sensitivity VERY POOR. Your current system noise figure is abysmal:

8 dB coax loss + 4 dB (or worse) distro amp = 12 dB in front of the HR20. I can't describe to you how terrible this is. Your system noise figure should be no worse than 3 dB for good performance. Notice we aren't talking about "gain"...forget gain...it's virtually meaningless. As long as your low noise preamp has at least 10 to 15 dB of gain (and they all do), and no more than 20 to 25 (lower is better in this range), it will do its job fine. Gain is the big liar as far as amps go...NOISE FIGURE IS EVERYTHING!

So...get the mast mounted preamp, put it out where it belongs and then just fiddle with the amount of input signal your HR20 is seeing and you should do fine....IF you aren't having lots of multi-path issues caused by a low gain (small) antenna and terrain that reflects a lot of signals. (large obstructions like buildings, sharp hills (as opposed to rolling pasture), water towers, etc...close to you and in between you and the transmitter site (same direction, or in line behind you from the transmitter direction).

I would call solid signal and ask them (after you tell them where you are and how far you are from the transmitter site), what kind of antenna they would recommend, along withe the CM 7777 preamp.

One more point of advice on this topic...

The distribution amp I have is the Winegard HDA-200. It is rated as the following:

Forward gain: +24dB 54-1000 MHz
Variable Attenuation: 0dB-18dB
Reverse Path Gain: +12dB 5-42MHz

Do you recommend I try to play with the screw (only one on it) that is labelled "Gain Adj"? I assume that this is for the variable attenuation.

Where would you recommend I put the amp/attenuator? Near the HR20?

[Milominderbinder2]

baesterling,

I could not add a thing to what you have been told except to give you the links you need.

The Winegard HDA-200 is probably the wrong amp. You need a pre-amp up on the antenna like Hasan noted. That Winegard is just amplifying your problems. Sorry...

I agree with everyone else that no one is as good as solid signal. It is not just that they have good prices. They will walk you through the right setup. They suggested the CM 7777 (http://www.solidsignal.com/prod_display.asp?prod=ANC7777) pre-amp for me with a CM 3020 (http://www.solidsignal.com/prod_display.asp?PROD=ANC3020) antenna and it has been amazing.

These are excerpts from the FAQ (http://www.dbstalk.com/showthread.php?p=870155#post870155)...

Adding More HD Channels to Your HR20 (http://www.dbstalk.com/showthread.php?p=870155#post870155)
HDTV Magazine (http://www.hdtvmagazine.com/programming/broadcast.php) is your source to see what is possible.

The best source I know of for all of the amps (http://www.solidsignal.com/cat_display.asp?main_cat=03&CAT=Amplifiers), splitters (http://www.solidsignal.com/cat_display.asp?main_cat=03&CAT=Splitters), and antennas (http://www.solidsignal.com/cat_display.asp?main_cat=03&CAT=TV%20Antennas) is Solid Signal (http://www.solidsignal.com/). Their prices are great and they ship almost instantly. They will also talk you through getting exactly the right equipment if you call them at: 866-374-4625.

I upgraded to a decent antenna for about $70, Channel Master 3020 (http://www.solidsignal.com/prod_display.asp?PROD=ANC3020). That helped a lot. 16 channels were now at 50% or higher signal. (If you call Solid Signal, they will match up the right antenna for your situation.)

I finally got a $65 Channel Master 7777 (http://www.solidsignal.com/prod_display.asp?prod=ANC7777) from Solid Signal. WOW! That worked.

- Craig

[hasan]

Well, I am using a Winegard SS2000 that has a pre-amp built in. That pre-amp has a 12db gain. When I called Winegard, they felt that a distribution amp placed after the pre-amp may be overkill and actually recommended a splitter at the TV. I have done both. Actually, from my brief test trials, it does seem that I have more problems with the distribution amp connected. The sound loss and pixelization appear to be fairly random, but I experience them on all HD locals. Some shows will be just fine, and others will have intermittend sound loss and pixelization. It rarely lasts more than a moment, but sometimes those moments are back to back, with sound coming in and out. The problem seems to be much more with audio dropouts than video pixelization.

I believe with the SS2000, it is directional and I am pointed in the right direction. There are no trees, hills, etc. blocking the antenna and the sky in the direction that it is pointed.

Would it help to put the distribution amp near the antenna? I tried that momentarily, but did experience the sound dropout.

Without the distribution amp, I think I have the setup you are recommending:

antenna with pre-amp>power inserter>150 feet RG6>splitter>HR20

Probably the only thing I have not tried is the variable attenuator. This may be consistant with what Winegard was saying when they said they were worried I was getting too much signal.

Any other thoughts? I really appreciate the input.

I don't have any time to look up the SS2000 right now, but as I recall that is not a very directional antenna, making you VERY vulnerable to multi-path distortion (reflections). I'll try to comment more in the a.m. as I have time. Everything else looks good in your description.

(keep bypassing the distro amp...not needed).

[veryoldschool]

One more point of advice on this topic...

The distribution amp I have is the Winegard HDA-200. It is rated as the following:

Forward gain: +24dB 54-1000 MHz
Variable Attenuation: 0dB-18dB
Reverse Path Gain: +12dB 5-42MHz

Do you recommend I try to play with the screw (only one on it) that is labelled "Gain Adj"? I assume that this is for the variable attenuation.

Where would you recommend I put the amp/attenuator? Near the HR20?
I would "think" that the amp will do you no good. +24 dB - 18 dB= 6 dB gain still. What you might have [since you see 100%] is too much gain [the 100% could be 120%]. As Hasan mentioned, a variable attenuator that could lower what you already have might do you some good. Point being: if your signals all came in at 90% you know you're not saturation the receiver & since it's digital 70% works as well as 100% [for picture quality]. Once you get it down from being "pegged", you might then see it "bounce" which is a sign of multi-path problems. The cheap attenuator [only] should give you [us] some idea of whats going on.

[veryoldschool]

• Average beamwidth: 61°
• Average VSWR across band: 1.3:1
• Average Front to back: 13 db
• Average gain across band 470-806: 4.5 db
• Maximum Width: 16 x 16 x 4
• Comes with J-Type Mast and Mount.
• Range for Channels (2-6): 0-10 Miles (Analog), 0-15 Miles (Digital)
• Range for Channels (7-13): 0-35 Miles (Analog), 0-40 Miles (Digital)
• Range for Channels (14-69): 0-45 Miles (Analog), 0-50 Miles (Digital)

These are the specs for your antenna. For what "I" think an antenna should be, this isn't the best.
My "average gain" is 13 dB without the amp.

You might look here: http://www.solidsignal.com/winegard_antenna_chart.asp

[baesterling]

Could another symptom of multipath be the signal meter jumping around a bit? It seems to jump around a bit before settling in at 100%. Should I shoot for a setting of 90% or so using an attenuator. the Fox channel (which is less than 100%) seems to jump around from the high 90s to the 80s. Maybe this is also due to multipath? I am not sure where to pick one up locally so I can try without waiting for shipping...but I may try Radio Shack and give this a try. Any other recommendations?

[veryoldschool]

Could another symptom of multipath be the signal meter jumping around a bit? It seems to jump around a bit before settling in at 100%. Should I shoot for a setting of 90% or so using an attenuator. the Fox channel (which is less than 100%) seems to jump around from the high 90s to the 80s. Maybe this is also due to multipath? I am not sure where to pick one up locally so I can try without waiting for shipping...but I may try Radio Shack and give this a try. Any other recommendations?
My going to have to take a step back, because I don't like your antenna. It might be "ok" but it goes against my 30-40 years of RF and so I'm too biased.

[Milominderbinder2]

...but I may try Radio Shack and give this a try. Any other recommendations?
Please don't. Please just call Solid Signal tomorrow and hear what they say.

- Craig

[hasan]

BTW, is there univeral agreement that solid copper vs copper clad does not make a difference? Solid Signal recommended solid copper and of course the RG6 that was installed during house construction is copper clad...

For OTA with no preamp, there is no advantage whatsoever of one over the other. If you have a mast mounted preamp, you might (for very long runs) need solid copper. RF (the tv signal itself), travels only on the very outside "skin" of the wire, hence the copper cladding. DC power, on the other hand, uses the entire volume of the wire, and solid copper has lower resistance than copper clad.

For satellite runs, solid copper would be desirable on longer runs for sure, as they carry DC current.

For OTA the only possible effect would be for power to a mast mounted preamp. The RF signal never sees the "core" of a piece of copper clad wire. If I was starting from scratch, I'd use solid copper. If I already had copper clad and my run was 100' or so, I wouldn't worry about power to the preamp...the preamp is should be driven by a voltage regulator ...so as long as you get enough voltage to the preamp to drive the regulator (let's say 8 volts or so), the preamp won't work any differently at 8 volts than 12.

There are a few variables to consider such as how much starting voltage you have in the house, then it's just a matter of how much voltage drop you have in the cable run to the preamp. I wouldn't start getting concerned until I had a run of well over a 100'. Of course, you could easily measure the voltage at the antenna end of things to see if it was enough to run the preamp...easier than running new cables.

Again, if starting from scratch or starting over, use solid copper, but don't replace for OTA just to feel better.

Do yourself a favor, forget Radio Shack (unless you really know what you are doing)...call Solid Signal and follow their advice. Seeing the specs on your antenna, I don't think much of it. Start over with a good antenna (since you are having problems and they may include multi-path). Be sure to tell Solid Signal that you think you are having multi-path problems.

[gabe23]

There are planes occasionally as we live about 20 miles from the airport (in about the same direction as the towers). I think the signal is pretty strong as it is 100% on all locals (except for Fox which is 95-98%). I think I will give this a try.

baesterling, I live a little closer to RDU than you do (near the Wake/Durham line), and I can definately say that the airplanes cause occasional dropouts for me. But I'm sure you'll be able to improve your reception with some better equipment. I use an old 6' boom antenna in the attic (with 90' cable run to the HR20), and with no preamp it picked up everything great when I had the H20. But when I upgraded to the HR20, everything went in the crapper. With some fiddling I could still get most channels, but I completely lost WUNC in Chapel Hill. I ended up adding a CM7777 preamp, and it made a BIG difference in the overall OTA signal. WUNC is still flakey, but I generally pick it up well at night, which is the only time they broadcast in HD anyway. I'm really hesitant to do anything more, since the H20 and my two HD sets have nearly flawless OTA reception. The tuners in the HR20 just are not very good, which is baffling to me considering this is the flagship product for D*...

By the way, that Winegard antenna you've got nearly lost to a $3.99 bowtie antenna taped to a cardboard box in this review:

http://www.hdtvexpert.com/pages/winegardss.htm

Like others have said, I'd call Solid Signal if I were you. They ship stuff really quick, and if something doesn't work, they'll let you return it without a hassle. And please, just say NO to Radio Shack and their overpriced, inferior quality products...