Cable signal quality issues -- do I need an amp?

[null_pointer_us]

We have the following:

cable line to house

external 2-way splitter

internal 4-way splitter

cable line to Family Room HDTV cable box
cable line to unused Family Room wall jack
cable line to MBR cable box
cable line to Kitchen cable box

internal 4-way splitter

cable line to unused Bedroom 1 wall jack
cable line to Bedroom 2's Hauppauge PVR-150
cable line to Bonus Room's Hauppauge PVR-500 (1)

Tuner #1
Tuner #2

cable line to Bonus Room's Hauppauge PVR-500 (2)

Tuner #3
Tuner #4

We've had signal quality issues for some time now. Certain stations constantly have diagonal lines of varying contrast through the picture. Other stations have a second or two of wildly distorted color before being fully tuned in (and are then normal). However, scheduled recordings would always complete (even if mildly distorted).

When I added the PVR-150 as shown above, we began to have lots of failed or incomplete recordings from the other server w/ the two PVR-500's. Often the first five minutes or last hour and a half -- yes, it's that bad -- will fail to record and be completely "red" in the progress bar. With four tuners, there are no scheduling conflicts.

Watching live TV and changing channels will occasionally show "No Signal" with a black screen in Sage -- but only on certain channels. Which channels appears to be quite random, probably as a result of how Sage is constantly switching to different tuners behind the scenes as I'm hitting the channel changing buttons.

All devices are fine except the two PVR-500's in the Bonus Room server, and of course all devices suffer from some sort of constant visual degradation on certain channels.

So my question is this: is my cable signal being split too much, and do I need a cable amp? I've heard that the cable company normally only supplies enough "signal" for two TVs and that the extra splitters just create problems, but I'd really like to be sure before spending money.

Thanks in advance!

[flavius]

Could you get some one from cable company stop by to take a look? Those amps can be tricky. While they help somewhat for some, they make matters worse for others..

[MeInMaui]

That does seem like an awful lot of splitters. Just by very rough calculation, it looks like you have less than 2% of the original signal strength getting to the tuners in your PVR500's. I use a distrubution amplifier (mine is an OnQ, though there are others) that splits the incoming cable into 6 outputs, each with a gain of 1 (i.e. each output has the same signal strength as the input).

I would recommend placing a distribution amp as close to the source as possible (ideally the incoming, unsplit cable) and distribute the signal with no additional splitters from there. Note that the PVR500 cards internally split the signal between the 2 tuners. That is unavoidable. HTH

Aloha,
Mike

[null_pointer_us]

flavius:

I'd rather not call the cable company. Comcast support reps. are a hassle to work with on technical issues, and they're incapable of communicating with the subcontractors who would be doing the actual work. Case in point: we ordered HDTV service, and the installer showed up with an invoice calling for only SDTV digital STBs. What a mess!


MeInMaui:

Thank you very much!

Cable distribution amps seem rather expensive at the retail sites -- 8-way boxes are going for upwards of $80 w/ shipping -- so I will be bidding on some (new/sealed) amps on eBay. I figure that with an M-to-M adapter, I can eliminate the external splitter and connect one of those cable lines to the 8-way dist. amp. Luckily, both the existing 4-way splitters are sitting in the attic and so will be easily replaced.

[MeInMaui]

Originally Posted by null_pointer_us

MeInMaui:

Thank you very much!

Cable distribution amps seem rather expensive at the retail sites -- 8-way boxes are going for upwards of $80 w/ shipping -- so I will be bidding on some (new/sealed) amps on eBay. I figure that with an M-to-M adapter, I can eliminate the external splitter and connect one of those cable lines to the 8-way dist. amp. Luckily, both the existing 4-way splitters are sitting in the attic and so will be easily replaced.

You're welcome.

Good luck. The price you give sounds about right. I think I got my 6-way amp for ~$80. But when I consider how much the rest of my equipment cost, $80 seems like a small investment to get it all to actually work. Anyway, please keep us updated.

Aloha,
Mike

[stevech]

you'll need an amp for that many splitters.
A $30 amp + separate splitters is the same as one of those expensive distribution amps. Not as elegant.

Be sure to get an amp with a reverse path filter so you cable modem or STB can send its signal out.

Buy a high quality amp so the noise increase is minimal.

[null_pointer_us]

I got an 8-way electroline amp for about $8 on eBay. Of course, the shipping was about *cough* $22.50 *hack* *cough* but it's still a good deal so long as the item really works.

Unfortunately, it doesn't have a reverse path filter, but I could always split the input to the HDTV STB and the 8-way splitter without compromising the signal quality quite as much as it is presently.

Thanks again for the advice, and we'll see what happens in a few days.

[null_pointer_us]

The amp, an Electroline 8-way (model EDA-UG2802), arrived today. Installation was a snap--but still have to ground it!--and it worked properly out of the box with no adjustments available/required.

This distribution amp does have a 10dB reverse path loss, but we're quite happy with our DSL line and have no need for interactive cable stuff, so the loss doesn't matter. On the upside, the signal boost is 0dB directly from the main house input to all 8 cable devices, so there's zero input loss and supposedly little chance of artifacts from excessive boosting.

All devices look great on all channels, with the exception of some crazy red distortion on channel 66; however, this problem was present long before the amp. What the amp did remove was the excessive color noise and minor ghosting that was plaguing the house. I'll keep my fingers crossed as to whether the two PVR-500's "no signal" problem has been fixed.

The picture improvement is excellent--easily the best $30 I've ever spent.

A big thank you for everyone who participated!

[MeInMaui]

Awesome. It's nice to hear a success story every once in a while.