PQ from "Digital Cable" - how to improve local channel reception? (1 Viewer)

[Vito_Jr]

Hi, I just had "digital cable" from att installed. Most of the channels look great on my 42" plasma, but the local (4,5,7) channels are somewhat grainy. I have to play with the coax cable to get a clearer picture - It reminds me of the old rabbit ears.

Once I have it tweaked the picture is very acceptable - not as crisp as the "digital", but clear enough (no static or grain).

I am suprised that with a coax connection I need to move the cable around for the different channels (4,5,7).
Are there better quality cables and connections that will give me a clear picture without having to play around the cable? I am using the stock coax that came with the cable box - it has the screw-on type connector. And I am feeding the video out from the vcr into the bnc connector on the plasma.


Thanks...

 

[jeff peterson]

I have a similar problem with our local channel 6. I've spoken with the cable tech and apparently it has such a strong signal that the cable itself acts as an antenna. So, the TV gets the cable channel 6 signal as well as a weaker OTA channel 6 signal. I think he said it's more common on the lower channels, too.

 

[Bob McElfresh]

A few things going on:

First, sometimes your local channels arrive at your CATV office via an ANTENNA. Then it gets digitized/compressed and sent through the coax as digital. This may be why these channels are grainer.

Second, moving the CATV cable should not cause any change in the picture unless you are moving it near/away from power cables that could cause interference. And if this was the case, moving the cable away should make all channels better. (I get the impression you move the cable one way to make channel 4 look good, and another way for channel 7).

It sounds to me like you have a loose connection or a bad cable.

Do this:

- Trace your CATV coax into your house. Un-screw every connector and examine the center wire. Is it bright copper or dull-brown colored? Cut the end off and replace every connector if the copper is brown. Also, replace every connector if it looks loose/has strands of wire shield poking out around the ends.

- Tighten every connecter hand-tight, then use a wrench to tighten it 1/4 turn more. Loose connectors are the number one cause of support calls in CATV systems.

- Then, if you still have the problem, replace that final piece of wire with a fresh one from say Radio Shack or Best Buy. DO NOT buy expensive wire, just another piece of pre-made coax and make sure the connectors are tight.

Now, does the picture quality still change when you move your final piece of coax? If so, it's time to call your CATV company. They will come out with some equipment that tests the signal strength for those channels and they will back-trace through your coax out to the stuff they string house-to-house.

When I had a problem that some channels had noise/snow, but others looked fine, they came out and traced all the way back to a pole behind my house. They found a jumper wire at the top that local wild-life had been snacking on. It affected some channels more than others. I suspect you have a similar problem - some stations are marginal and when you move your coax, something pushes the problems over the edge to make them visible.

Try this and let us know what you discover.

 

[Hanson]

I thought that "digital cable" applied only to channels above 100. All other channels are regular analog, which is why you can receive these without a digital box.

This is why I never got digital cable -- 99.9% of my viewing was between channels 2 and 100.

 

[Vito_Jr]

Bob - you were exactly right - loose cables seemed to be the problem.

I started (and ended) with the cables going in and out of my components. First I moved the coax from the cable box into the vcr away from the power cables as much as possible. I then looped the cpoax a bit to keep it from dangling. I then reinserted and tightened each cable connection. The picture quality improved 100% to the point where there is no visible grain or static on any of the local channels.

Thanks for pointing out something that was so simple.

As far as the connectors - the cable guy told me that when I got my plasma (it came 1/2 hour later than the digi cable installation) to call them back as they install "compressed" connectors as opposed to screw on connectors. He purported that the compressed were better - any comments?

Hanson - you may be onto something here. Since I did not have the "regular" cable installed with my plasma I have nothing to compare it to. I also understand that the digi channels are over 100 - but I do have HBO that come in with a digi signal. There are sometimes though the regular HBO looks as good as the digi channels.

At this time I am very happy with the PQ on all the channels. Actually the digi pkg is costing $2/mo less than the regular.

Thanks for all of the good suggestions!

 

[Bob McElfresh]

The Connectors: There seem to be 3 types of "F" connectors:
- Screw on
- Crimp on
- Compression Fit
I would avoid the screw-on type as they depend on having the proper size cable to screw onto. (This is for the tool-challenged).
The Crimp On are some of the easiest to do with a crimp tool. You can get the $20 hex-crimp tool from Radio Shack. Or you can buy a nice ratching crimp tool (called a "Crimp Frame" and a separate die set for either RG6 or RG59. Then you buy the "F" connectors with the built-in crimp ring and go to town.
The Compression type are a ultra-heavy duty connector made from non-reactive cadimum, and they have a rubber "O" ring where the coax shoves into the plug. These are ment for outdoor use and have a 10-20 year life time. Overkill for indoor use, but if the guy will do it for you, great.
You should have in your tool box:
- A coax cable stripper ~$15 from Radio Shack
- A crimper like I mentioned above
- A "T" handle to shove the connector onto the coax ($4 at Radio Shack)
- A box of F connectors from an electronic supply store. I highly recommend the ones with the built-in crimp ring.
This is another cool tool you can pick up at your local Home Depot:
Ideal Coax Tool
The part number is Ideal 35-046 (makes a great stocking stuffer for about $16).
And I'm serious: trace your coax all the way through your house and check for tighness and dull-brown copper (oxidization). I do this once per year as a part of my "HT Cleaning". And often, just disconnecting and re-connecting the coax and your HT cables can prevent problems.
Glad to have helped.