[mythtv-users] OT: Signal-to-noise ratio

Allen Edwards allen.edwards at oldpaloalto.com
Fri Aug 29 03:25:43 UTC 2008

On Thu, Aug 28, 2008 at 7:26 PM, Bob <mythtv at cox.net> wrote:
> Allen Edwards wrote:
>> The kind of coax you use can make a large difference in a cable system
>> because cheap coax will let OTA signals in and they will look like
>> noise to the cable signal.  Cable companies use RG6U Quad Shield Coax
>> for this reason. Typical Radio Shack Coax will give the problem you
>> are seeing.
>> Allen
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> Thanks for the tip.  I am using quad shield RG6, I know because I put it
> in myself.
> More mysteriously, I friend that lives 15 miles north has an HD-3000
> card with less signal strength and less SNR and it recording OK.  Not
> sure what to make of it.
The other thing to check is the ground connections.  If for some
reason you didn't get a good ground connection on one of the
connectors, either on the connection you made or on what you are
connecting to, that will also turn your cable into an antenna.

If there is any way you can disconnect the cable or the feed from the
cable company you might be able to connect an analog TV up to your
cable and see if you have a strong signal there.  Of course, you
should have no signal at all if you terminate the end of the cable.
You can take a barrel connector and put a normal size paper clip in
the center conductor and wrap it in aluminum foil to terminate the
end.  It would be ideal if you could disconnect at the pole, but as
far away from your TV set will at least tell you about that part of
the cable.


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