I have two Hauppauge HVR-1600 tuners that I'm using to record over-the-air digital broadcasts. According to antennaweb.org, the seven UHF stations I'm interested in are all 20-21 miles away, and all are between 222 and 224 degrees from my house. We live about 1500 feet up on a mountain, with lots of trees, but no other obstructions.

I started out with a Philips desktop antenna (not amplified), with a splitter to send the signal to the two tuners. I averaged around a 22 SNR level on most channels, but the signal seemed to drop below that enough to make recording unreliable.

So, I bought a Motorola 10db amplifier and added it between the antenna and the splitter. No real change. My SNR may have increased 1 point, but that's it. Still couldn't record reliably.

So, I bought a Channel Master 4221 DB2 style antenna and mounted it up in our attic. There's approximately 25 feet of cable from the antenna to the tuners. My SNR is now around 23 without the amp, or 24 with the amp. Most of the time this is stable enough to record the shows I'm interested in, but I still get occasional fluctuations that drop below 20 or so which results in scrambled recordings (usually the shows I'm most interested in.).

For a variety of reasons, I do not want to install an outdoor antenna, but I do not have space for a DB4 style antenna, or a larger directional style in the attic. Is there any way to add a second DB2 style antenna (aimed in the same direction) and combine the two antennas into a single feed? Would this boost my signal any, or would it just introduce more noise issues?

Would adding a higher gain amplifier be of any use? What about adding a second amp inline with the first?

I also have Comcast cable coming into the house, but unfortunately my HVR-1600's won't tune that reliably either (QAM needs even stronger signal strength?).

I've tried about every recommendation I could find, but nothing really seems to make much difference in my signal. The DB2 antenna in my attic with an amplifier only gives a couple of points higher SNR than a piece of wire laying on the floor and jambed into the coax connector. :) Something just doesn't seem right to me.

I have a different tuner on order to see if it's just the tuner's fault, but in the meantime I'd like to investigate what other options I have left for improving my signal.

Thanks,

Anthony

Have you tried 2 antennas for 2 tuners and leave them separate from each other ie don't combine the signal?

I've tried one antenna with one tuner (i.e. no splitters). No difference. Same SNR levels.

According to TVFool, I should have about -45DB signals in my area. As a general rule, they say anything above -70DB should be strong enough for a desktop antenna. But I can't seem to get a strong enough signal for my tuners even with an attic antenna and an amplifier.

Anthony

I'm still looking for ideas...

Can I combine a second DB2 antenna (pointed in the same direction) with my existing DB2 antenna to boost the signal? Or would that just cause further problems.

I don't have the height for a DB4 antenna, but there is plenty of room for DB2's lined up side by side.

Anthony

Oops, I need to make a correction regarding my setup. I kept thinking I had a DB2 antenna, but I took another look and I actually have a Channel Master 4221 I bought from Amazon that is rated for 45 miles. That's more like a DB4, correct?

All of my stations are less than 22 miles away, with no major obstructions in the way.

My cables are all new with nice solid connections, I've tried with and without a Motorola 10DB amplifier, and I've fine tuned the aiming of the antenna a few different times (I use a remote desktop software to take my laptop right to the antenna and can watch the SNR levels as I adjust the antenna).

I just can't get anything more than about a 23 SNR average, which is OK "most" of the time, but it occasional drops below 20 and my recordings end up scrambled.

What am I doing wrong? How can I improve my signal?

Thanks,

Anthony

Cut down the trees (or if they're not your trees, hey fires happen all the time). :D

On a more serious note. You shouldn't be having that much trouble at only 20 miles away unless the stations are still at low power or the trees really are in the way.

The ultimate solution would be a big outdoor mast to get you above the trees. But since you don't want to do that (which I completely understand since I have a similar situation)...

The only other thing I can think of (assuming all the stations are UHF) is to try a Yagi instead. I used this one because it was cheap ~$35 (the 3020 might be a better choice for you):

http://www.pctinternational.com/channelmaster/0612/3018.html

And since it comes in three pieces, so I was able to just throw away the two-piece VHF part and just use the UHF Yagi part which makes it a lot easier to fit in an attic.

Trying a Yagi will be a bit of a crapshoot. It should give you a little bit more gain and especially some better directionality which might help you get a more consistant signal through the trees. But it probably won't have as flat a passband as the 4221, so it might make some channels worse. :(

Mac,

Thank you for your response.

Nope, cutting down trees is not an option. That's one of the reasons we chose to live where we do. I'll lose the TV before I lose the trees.

I agree, I shouldn't be having this much difficulty being only 20 miles from the transmitters. According to TV Fool, most of my local stations are 1000KW, with a few 750KW.

And like I said, I'm not really getting any better signal with the antenna than I did with a basic piece of wire.

I'm really starting to suspect the tuners themselves are at fault. I have a different tuner coming on Wednesday, so I hope that'll help me diagnose things a little further.

Anthony

What kind of building materials are you receiving through? Roof or gable end? Is there anything metallic involved?

If there is anything metallic surrounding your attic - give up and put the 4221 outside (I didn't even try putting my antenna in the attic when I saw the metallic sheathing). You could also consider a preamp (I'm also using one of them - a 19 dB Winegard knocked down by an attenuator). The Preamp makes up for cable losses.

FWIW - I'm also in the trees, at 22 miles or so to the antenna farm, and I get superb reception doing that.

Raouliii,

Just the wood roof structure (rafters and sheathing), nothing metallic in the way.

I tried multiple locations around the house before installing the antenna in the attic, and didn't notice any difference in signal strength. Like I said, a piece of wire on the floor did just about as well.

Scooper,

I'm already using a 10db preamp with the antenna (mounted in the attic, just after the antenna). Still, my SNR is only about 1 point higher with the amp than it is without it.

Thanks,

Anthony

Raouliii,

Just the wood roof structure (rafters and sheathing), nothing metallic in the way.

I tried multiple locations around the house before installing the antenna in the attic, and didn't notice any difference in signal strength. Like I said, a piece of wire on the floor did just about as well.

Scooper,

I'm already using a 10db preamp with the antenna (mounted in the attic, just after the antenna). Still, my SNR is only about 1 point higher with the amp than it is without it.

Thanks,

AnthonyIf your antenna is providing the same gain as a piece of wire on the floor, there is a problem. When the preamp is inline, how is it powered? Are your connections tight with no internal shorts? Check your cabling and connections to the antenna thoroughly. Make sure the antenna is deployed correctly and pointed in the correct direction (dipoles facing the transmitter).

Raouliii,

> If your antenna is providing the same gain as a piece
> of wire on the floor, there is a problem.

Not the same, but not as much of a difference as I would think.

When I first got my HVR-1600 tuners, the only "antenna" I had available was a piece of wire. I didn't have the SNR meter available then, but most channels still came in fairly well, other than the frequent stuttering and dropouts.

I took that as a sign I had a fairly strong signal in my area, and quickly bought a Philips desktop HDTV antenna and was getting SNR levels around 21 on average. But it was still skipping badly.

So, I bought a Motorola 10db amplifier to boost the signal. That brought my SNR up to about 22 on average. Stuttering was less, but still way too frequent.

Next, I upgraded to a Channel Master 4221 antenna in the attic (without the amp). SNR was up one more point to 23 or so, but still too many errors in the signal.

So, I added the amp from my first antenna to the 4221, which brought me up to my current SNR of 24. Like I said, "most" of the time this is fine, but I still get too many errors which corrupt the recordings.

I've gone over the connections multiple times in the process, and used a variety of different cables, so it's unlikely to be a cabling issue. The thing most surprising to me is how insignificant each step of the process has improved the signal. Generally only 1 point at best, when I'd really like to bring the SNR up 5-6 points. I would have expected a much larger gain between a desktop antenna and a larger amplified antenna.

As for aiming the antenna, I've made the full 360 degree swing to determine the optimum direction for the antenna (watching the SNR levels as I adjust). I also double-checked my final position with a compass and it correlated with the directions listed on antennaweb.org.

The only remaining weak link I can see are the tuner's themselves.

Anthony

Are there any analog UHF stations on the same tower as the stations you're interested in?

If yes, then it's time to plug that antenna into a regular old analog TV and see what it looks like. Maybe then we can figure out what's going on. Oh, you should probably remove the amp first since if you aren't blocking the power properly that would destroy the reception and you really shouldn't need it anyway.

..... Oh, you should probably remove the amp first since if you aren't blocking the power properly that would destroy the reception and you really shouldn't need it anyway.Good point. You must remove the amp if you are not providing power to it.

I apologize for not being more clear. My amp DOES have power, and it does raise my SNR by about 1 point. So for now, it seems to help more than it hurts.

As for analog UHF stations on the same towers, I'm not sure. I don't have a TV available near the tuners, so I would need to do some cable swapping on my tuner cards to test that out.

However, my OnAir GT tuner is supposed to be here Wednesday, so I'll probably just wait and see how that performs before making any other changes.

I'm curious. What are the signs of TOO much signal? Does anyone sell a variable attenuator that I could try adjusting the signal strength to see what effect it has?

Also, my cables are all new, but are RG-59. I usually see RG-6 recommended. For a 25' cable, would I really notice any difference by switching to RG-6? It's not exactly an easy installation, so that would be a very last resort.

Thanks,

Anthony

RG-6 is definately preferred over RG-59, simply because it will lose less signal over an equal distance. But I don't think your issue is primarily the RG-59 - a contributing factor, certainly, but not the main reason.

...
I'm curious. What are the signs of TOO much signal? Does anyone sell a variable attenuator that I could try adjusting the signal strength to see what effect it has?

...


There are fancy attenuators, but it's generally cheaper and easier for regular people to just use splitters to attenuate the signal.

.... Oh, you should probably remove the amp first since if you aren't blocking the power properly that would destroy the reception and you really shouldn't need it anyway.

I guess I should clarify this since there seems to be some confusion.

If you're using an amp that gets it power through the coax cable, then you also need a splitter that "blocks" the power on at least one of the outputs. The tuner(s) have to be connected to one of those outputs otherwise the power signal will destroy your reception.

Again, I'd suggest just removing the amp until you get something working since you really shouldn't need it anyway and it makes it more complicated to troubleshoot.

Mac,

OK, I see what you're saying, and no, my amp has it's own power connection separate of the input and output connections.

I took some time this morning to do more testing with my antenna setup. First, I unhooked the pre-amp and took the direct feed from the antenna:

KOIN-DT, 6.1 CBS, 221 degrees, 20.7 miles, Frequency: 40, SNR: 19.1

KPDX-DT, 49.1 MNT, 224 degrees, 21.2 miles, Frequency: 48, SNR: 25.4

KGW-DT, 8.1 NBC, 223 degrees, 20.9 miles, Frequency: 46, SNR: 25.3

KOPB-DT, 10.1 PBS, 223 degrees, 20.9 miles, Frequency: 27, SNR: 26.6

KPTV-DT, 12.1 FOX, 223 degrees, 21.1 miles, Frequency: 30, SNR: 25.0

KRCW-DT, 32.1 CW, 221 degrees, 20.6 miles, Frequency: 33, SNR: 19.3

KATU-DT, 2.1 ABC, 221 degrees, 20.7 miles, Frequency: 43, SNR: 26.4

The readings were actually a little higher than I've seen in the past, but that seems to fluctuate with weather and time of day.

Then I reinstalled my Motorola Amplifier. It's rated for broadband use, and though it was sold as a 10db amp, it has 15db stamped on the amp itself? In any case, I was surprised to find absolutely NO improvement on any station except KOIN-DT. And even that was less than half a point improvement. A few stations even showed slightly lower readings with the amp installed. Weird. So, I removed the amplifier from my setup.

Generally, I've noticed anything below a 20 SNR results in scrambled recordings, At least two of my stations are there now, and I know many of the other stations fall to that level on other days.

Out of curiosity, I tried hooking the tuners up to my Comcast cable feed again and ran a scan of QAM stations. While it found 20 or so channels, none of them had an SNR high enough to lock on consistantly. SNR was generally around 32 on every channel, but that's only good for a yellow bar in the Hauppauge signal monitor. From what I could tell, I would need at least a 34 SNR consistently to maintain a lock on the station. I tried adding the amp here too, again with no change. So, as I knew from past experiences, my cable feed is currently not an option. The antenna seems to work better.

I'm thinking my amp might be toast, as it doesn't seem to have any effect whatsoever on the signals.

Also, someone asked about checking analog stations. I only have two available. Channel 32 had "color ghosting" issues (red and blue distortion around edges of people and objects) and the sound was fuzzy. Channel 49 was mostly clear, though with a slightly fuzzy picture.

My other tuner is supposed to arrive on Wednesday, so I'll see what results I get with it. Since it is a USB style tuner, I should be able to hook it to my laptop and take it directly to the antenna in the attic to experiment with different antenna locations.

Ironically, today seems to be a good day as far as signal strength is concerned. If signals were this strong every day, I wouldn't have any issues. Maybe the amp was dying and causing problems? I'll keep an eye on it and see how the SNR levels hold up.

Anthony

I noticed 2 things in your last post:

1 -- RG6 is what you should be using for any digital signal; an anolog signal may come through pretty good on RG59, but you need RG6 for digital.

2 -- I talked to Hauppauge Support last Saturday because my WinTV 1600 would find many Clear Qam channels but only display just 4. They said that there is a software problem which prevents their tuner from displaying Comcast Clear Qam. They said the problem should be resolved this week and an updated released. (I checked their website 10 minutes ago -- there is not yet an update.)

escmb,

> an anolog signal may come through pretty good on RG59,
> but you need RG6 for digital.

That's what I've been hearing, but it would be a major undertaking to rewire the house right now. Maybe this summer.

Still, I have no problems anywhere else with RG59, including the internet cable modem and my Samsung plasma TV. It's only the HVR-1600 tuners that won't lock onto the signals reliably.

> They said that there is a software problem which prevents their
> tuner from displaying Comcast Clear Qam. They said the problem
> should be resolved this week and an updated released.

Interesting. Good to know. Thanks for the info. Maybe that will help resolve the cable issues and I can stop fighting with the antenna. We'll see...

Anthony

....

Then I reinstalled my Motorola Amplifier. It's rated for broadband use, and though it was sold as a 10db amp, it has 15db stamped on the amp itself? In any case, I was surprised to find absolutely NO improvement on any station except KOIN-DT. And even that was less than half a point improvement. A few stations even showed slightly lower readings with the amp installed. Weird. So, I removed the amplifier from my setup.

....

Well you might be overdriving or the amp might be bad like you said.

If you have an extra splitter lying around try adding it into the chain and see if a lower signal level actually helps. I'm doubting it will but you might as well eliminate it as a possibility.

> you might be overdriving or the amp might be bad like you said.

I know at one point the amp added a full point or two to my signal level. So I was surprised this morning to see no real change at all, positive or negative. In any case, if the signal is strong without it, that's fine by me. One less thing to worry about.

Anthony

One big thing that blocks reception is moisture. If your roof is covered in snow, ice, and water your attic antenna is likely getting crap for signal. Particularly in winter, your roof may not look like there's moisture but there is snuck under the shingles and killing your signal.

Attic antenna are often only good for dry climates that don't collect snow, moisture, dew, or rain on the roof. Otherwise, in summer one should expect about a 50% signal compared to that of an outdoor antenna. Other than that, you pretty much have the bases covered (antenna, amp, etc.).

I guess I should clarify this since there seems to be some confusion.

If you're using an amp that gets it power through the coax cable, then you also need a splitter that "blocks" the power on at least one of the outputs. The tuner(s) have to be connected to one of those outputs otherwise the power signal will destroy your reception.......My Winegard preamp does not require any extra DC blocking component. My guess is that the power injector blocks the DC within itself, not allowing it pass to the tuner. I believe this to be a very common situation.

I noticed 2 things in your last post:

1 -- RG6 is what you should be using for any digital signal; an anolog signal may come through pretty good on RG59, but you need RG6 for digital.
......HOGWASH. There is NOTHING special about RG6 that makes it a "digital" cable. RG6 does usually have better construction, conductor size and material, and shielding over RG59.

RG6 is sometimes labeled as being "swept" to relatively high frequencies, such as 3GHz. These frequencies are associated with satellite reception equipment but certainly not with UHF/VHF digital broadcast reception.

The biggest issue for this application would be that RG6 tends to have lower attenuation per foot than RG59. Therefore, at relatively long lengths, RG6 would be prefered, especially if a preamp is not used.

My new tuner came today, an OnAir GT USB tuner. It's even worse than my HVR-1600 tuners! Skipping and stuttering badly whether I hook it to my antenna or to my cable connection. So, I'll likely be returning it.

However, I may hook the OnAir GT to my laptop temporarily to experiment with different antenna locations and fine tune the aiming.

I also contacted Comcast cable about my weak signal and they're sending out a tech tomorrow morning to adjust the signal level. So, I'll have to wait and see if that accomplishes anything. Otherwise, I'll have to continue my battle to improve the antenna reception.

Anthony