Bad channel

[ricecrazy]

My card works great, except for I've got one channel (channel 2, CBS in Los Angeles at 54 MHz) that has really bad horizontal lines.  Unfortunately, the sole purpose of setting up a PVR for me was to record episodes of CSI.  

Example of CBS:
http://www.rightonbro.com/gbpvr/bad.jpg

Example of a clean channel:
http://www.rightonbro.com/gbpvr/good.jpg

This happens on any PVR software I try (GBPVR, Hauppauge's WinTV2000, and BeyondTV when I tried that joint out a few weeks ago).  Hauppauge tech support says try a new coax cable (I did, no change) or a signal booster (haven't tried yet).  Are horizontal lines indicative of a weak signal?

My cable connection is as follows:
* Cable modem vs. TV on the first splitter
* TV is split - first goes to digital cable box, second goes to PVR
* Cable provider is Comcast (I'm on their digital starter package)

So technically I'm only pulling in analog cable and the PVR is receiving certain stations only (the public stations like CBS, NBC, and FOX), which is fine with me.  I might get an IR blaster and just use the PVR to record from the cable box, but I'd like to watch TV and record a different channel at the same time.

System is WinTV PVR-250 on an Athlon 2200+, 1 gig RAM, ATI Radeon 9800 Pro.

thanks,
mdj

[tieke]

Just a few fault-finding suggestions:

From what I understand from your description, you're using the unencoded free-to-air stations which are carried in on your cable alongside the normal digital ones.

The first thing to do would be to rule out problems with your setup - what does this station look like when you connect the cable currently going to your PVR directly to your TV instead? - if you're still getting the lines, try connecting to the TV before the splitter and see if that's causing it (splitters usually cause a signal drop of a few dB). If you are still getting inteference, see if you know someone else with Comcast to try doing the same thing to find if it's just you, or whether it's the general transmission.

[ricecrazy]

Quote[/b] (tieke @ Aug. 22 2004,18:46)]Just a few fault-finding suggestions:

From what I understand from your description, you're using the unencoded free-to-air stations which are carried in on your cable alongside the normal digital ones.  


The first thing to do would be to rule out problems with your setup - what does this station look like when you connect the cable currently going to your PVR directly to your TV instead? - if you're still getting the lines, try connecting to the TV before the splitter and see if that's causing it (splitters usually cause a signal drop of a few dB).  If you are still getting inteference, see if you know someone else with Comcast to try doing the same thing to find if it's just you, or whether it's the general transmission.

Quote[/b] ]From what I understand from your description, you're using the unencoded free-to-air stations which are carried in on your cable alongside the normal digital ones.

Yes, that is the case.

I forgot to mention that previous, the cable was going into a VCR, and the picture was fine. Only when I unplugged the cable from the VCR and into the PVR-250, do I have the problem.

I've been trying to research the issue, and it sounds like one of two things (forgive me if these are wildly inaccurate):

a) The Comcast tech told me that their setting for CBS is 54 MHz, which isn't standard. I tried tuning the pic in WinTV2000 and it indeed looks the best there. Maybe there is some sort of interference (from the computer or whatever) at 54 MHz, and a filter that eliminates everything under 54 MHz would do the trick?

b) He also mentioned something that the picture might actually be two frequencies competing with each other, or something like that. Like, the over-the-air version is conflicting with the cable version.

Any of this sound reasonable? Or should I just get a USB IRT and run the PVR-250 through my digital cable box? It would suck not being able to watch a different channel while taping...but then again, I hardly watch TV anyway, and the point of setting up the PVR was to record channel 2.

[ricecrazy]

Oh - forgot to mention that if I do plug in the cable that's going into the digital cable box, into the PVR instead, I get the same problem.

One thing I haven't tried is bypassing the splitter that splits the cable modem and the TV, thereby directly pluggin my apartment's cable into the PVR. But I can't unscrew the cable, and I don't have a wrench.

[JaxChris]

Whenever you have a problem with weak signal, the first thing Comcast will usually ask you is if your lower channels are clear. If you are pulling TV and internet on the same lead (lead = primary line off the box outside) then you're dropping your signal strength. Signal strength affects UHF channels, VHF channels and internet speed before it affects digital channels. You should try running your cable line straight to the PVR card first. If that does work then you will need a booster on that line if you want to continue using internet and TV on the same line. Comcast charges 50$ for the booster and install it free. They even warranty the booster as long as you keep service with them. Also, as for signal affects... the lowest channels are affected first, primarily channels 02-08 are the first affected. Channel 01 is not affected usually because 01 is an emulated digital channel recognized by your cable box. You can have Comcast come out on a service call, just tell them you are have problems with picture clarity on the low end channels, and they will meter your signal strength. Make sure it's between 5-7 right before that splitter, if it is, ask them to replace that splitter with one from their truck. The cable guys will usually help you get your signal worked out. But if all of this fails.... try returning your PVR card on warranty and see what happens... the card may have a problem.