QAM, HVR-1600, Amplifier?

[Anthony]

It helps to know that I might do better with OTA than QAM. I'll do some research on DB2 antennas (I haven't looked at OTA much). I am on Comcast, so that was good info, too. Perhaps there is some patch or upgrade for the 1600 to deal with QAM on Comcast.

If you decide to try OTA, you may want to visit http://www.antennaweb.org. You can plug in your address and it will tell you the distance and directions of all the stations available in your area.

Mine are all between 20 and 22 miles away in nearly the same direction. I bought a Channel Master 4221 from Amazon.com that works great for my situation. For what it's worth, I first tried the 4221 in my attic, but due to signal distortion from the building and wiring the reception was horrible. It was like night and day when I mounted it outside. Perfect signal after that.

Take care,

Anthony

[dennit]

I've got a service call in now.

Well, they came out and told my wife "the signal strength is fine." No actual numbers were provided and they couldn't tell me when I called.

I think I posted my current config - split immediately and send half the signal to the HVR-1600, one quarter to the digital TV tuner and the remaining quarter through the amp to the analog tuners.

I optimized signal strength at the HVR-1600 with the Hauppauge digital strength meter and have all channels except one at or above 30 with most about 32. I did find one other issue - my default mpeg decoder was causing stuttering, which I initially thought was poor signal strength. The system is running pretty good now, but what does this tell you:

While debugging the signal strength and stuttering issue, I decided I wanted the max signal strength so I took out the splitter and sent 100% of the signal to the HVR-1600 again. SNR dropped from 32.9 to 32.4. This was consistent with two different in-line connectors used to replace the splitter. I get better SNR with the splitter in place. WTF?? I know it's a small difference, but still?

Any comments on what I'm seeing here? I'd appreciate reports from anyone who has measured SNR ratios on an HVR-1600, or tested splitters or amplifiers.

[Anthony]

they came out and told my wife "the signal strength is fine."

Yep, that tends to reflect my own experience as well. I couldn't get any specific values out of the tech to research it further, only that it was "better than most".

my default mpeg decoder was causing stuttering, which I initially thought was poor signal strength.

I rarely watch Mpeg files on my computer, as I stream recordings over my network to a Tvix M-4000P in my living room. It works great as long as the Mpeg files are not corrupted.

The video card in my computer has hardware Mpeg decoding built-in for watching videos, so that's rarely a problem if I watch them that way either.

In my case, I could "watch" shows from Comcast QAM cable OK, but recordings always ended up scrambled. Sound was fine, but the picture was just random pixels everywhere. Pretty, but not real watchable.

I took out the splitter and sent 100% of the signal to the HVR-1600 again. SNR dropped from 32.9 to 32.4. This was consistent with two different in-line connectors used to replace the splitter. I get better SNR with the splitter in place.

I suppose it's possible your cable signal is actually too strong and overloading the HVR-1600 when connected directly. Try changing your splitter arrangement so the HVR-1600 gets even less signal and see if the SNR goes up or down.

More likely though, it's just a normal variance in SNR, or an issue with the cabling or connectors. Try wiggling the cables around while you watch the SNR and see if it changes any.

It sounds like you're having better luck that I ever did. Congrats!

Take care,

Anthony

[whurlston]

32.*db is a pretty good signal. I run at about 37db but mine is at the upper limit of the acceptable range. If I boost the signal any more, it overloads the HDHomeRun and I get errors in the stream. The reason you are seeing a drop in signal dbs when removing the splitter could be because of the splitter introducing noise.

When it comes to QAM, signal quality is actually more important than signal strength.

[dennit]

32.*db is a pretty good signal. I run at about 37db but mine is at the upper limit of the acceptable range. If I boost the signal any more, it overloads the HDHomeRun and I get errors in the stream. The reason you are seeing a drop in signal dbs when removing the splitter could be because of the splitter introducing noise.

When it comes to QAM, signal quality is actually more important than signal strength.

The channels at 32 db are pretty good. They are the lower frequency channels. I have some higher frequency channels that are about 29.5 - 30 SNR. I haven't really spent a lot of time recording or watching them since I fixed the mpeg live TV problem, so they may be OK now. They seemed to be marginal before, with some breakup or stuttering, but perhaps I was seeing a decoding problem.

Do you mind if I ask what you used to test your "boost the signal?" Was it an ordinary amp? I can't seem to use any sort of amplification before the two digital receivers (TV and HVR-1600) without hurting the digital signal. I'd like to be able to distribute the signal directly from the entrance to the house.

BTW, whurlston, thanks for MceEpg2XmlTv - I've been using that very reliably since Schedules Direct died for my standard def Tivos, but I'm now moving into HD recording and setting up GBPVR. (This isn't the place, but I'm having trouble with MceEpg2XmlTv on my second HTPC, which pulls the digital lineup, so I'm temporarily running yapi2xml - which also is a bit flaky. The first HTPC, which pulls another lineup, is still running great. You may see me in the MceEpg2XmlTv forum at some point though )

[dennit]

Try wiggling the cables around while you watch the SNR and see if it changes any.

I did try this - it's solid and the SNR doesn't fluctuate at all. I tried it three or four times with two different inline connectors. I'm thinking about putting in a variable attenuator, just to see what happens.

[whurlston]

The channels at 32 db are pretty good. They are the lower frequency channels. I have some higher frequency channels that are about 29.5 - 30 SNR. I haven't really spent a lot of time recording or watching them since I fixed the mpeg live TV problem, so they may be OK now. They seemed to be marginal before, with some breakup or stuttering, but perhaps I was seeing a decoding problem.

Yeah, that's about the low end of the acceptable range. If you could boost the signal, you might see and improvement. If your cable company sells a signal amp, I would recommend trying it. Mine sells a good one and they will split it up across 3 months on the bill.

Do you mind if I ask what you used to test your "boost the signal?" Was it an ordinary amp? I can't seem to use any sort of amplification before the two digital receivers (TV and HVR-1600) without hurting the digital signal. I'd like to be able to distribute the signal directly from the entrance to the house.

Any amp that will do up to 950/1000Mhz (1Ghz) should work, see above comment though. I use a two way splitter at the main feed taking one to my cable modem and one to the 4 channel amp. It over amps my signal slightly but I then use splitters to cut it back down before connecting to each device. NEVER amp your cable modem. You can burn it up pretty easily.

BTW, whurlston, thanks for MceEpg2XmlTv - I've been using that very reliably since Schedules Direct died for my standard def Tivos, but I'm now moving into HD recording and setting up GBPVR. (This isn't the place, but I'm having trouble with MceEpg2XmlTv on my second HTPC, which pulls the digital lineup, so I'm temporarily running yapi2xml - which also is a bit flaky. The first HTPC, which pulls another lineup, is still running great. You may see me in the MceEpg2XmlTv forum at some point though )

YW. I'm working on a C# version of YApi2XML since Oz is away serving our country and unable to respond to issues at the moment. I've just been pretty short on spare time lately.

[dennit]

YW. I'm working on a C# version of YApi2XML since Oz is away serving our country and unable to respond to issues at the moment. I've just been pretty short on spare time lately.

Wow, you get your data from Schedules Direct and still support two alternative grabbers! The community certainly owes you a debt.

I said that I was having trouble with MceEpg2XmlTv and yapi2xml was flaky, but what I probably wasn't clear about was that yapi's problem was on Yahoo's end, not yapi's, while the trouble with MceEpg2XmlTv was on the Media Center schedule grabbing side, not MceEpg2XmlTv (something to do with time synch, which I think is sorted now).

[whurlston]

Several of us started working on the alternative grabbers before SD was an option. Development on them is pretty much over though. I'm only rewriting the YApi2Xml because I now know more about the problems on Yahoo's end and it's easier for me to rewrite it than go back and learn VB6 again (it's been too long since I used it). If Oz were able to work on it, he could fix it pretty quickly.