Dwight,
An interesting problem, especially since I heard recently that some
community CATV systems are planning to run digital video on CAT-5 lines
around town. That's a truly scary thought. I have heard of one system in
another town that is working, but they did use SHIELDED CAT-5E cable
(verified by visual inspection by hams). In your case, a few questions
come to mind:
1. What is the orientation of this one problem set relative to your
antennas?
2. What is the connecting device between the TV and the phone lines? Is
it a passive balun or an active device "converter" box?
I saw K9YC's reply to your inquiry. Read and heed the info from his web
site. The grounds you have are very nice and good for system protection
from lightning damage, but this is strictly an RF overload problem
somewhere. If the TV was good on an outside antenna before, it is
probably not the set that is the problem now. You should concentrate your
efforts on the interface between the TV and phone lines, and don't forget
that if you use ferrites, be sure they are appropriate for the frequency
bands you are using.
Please keep us informed on your progress, and best luck.
73, Dale
WA9ENA
DGB <blueheron@Bayland.net>
Sent by: rfi-bounces@contesting.com
03/31/2008 07:18 PM
To
rfi@contesting.com
cc
Subject
[RFI] Digital TV Problems
I've recently had subscribed to a service thru the fone lines that
include TV and Internet. I've had the internet thru it for a long time.
I have 4 tv's in the house hooked to this system.
My shack is in a separate building but still about 30' from that problem
tv. I've a good single point grounding system that is all connected to
the tower, the service here in the shack, and the house's service. It's
all connected undergnd with 2" copper and gnd rods every 16' (over 30
rods).
Recently I've been getting into the TV when xmtg but just one of the
tv's. My signal scrambles the digital image, like tiling.
I never had that problem when the tv had an outside antenna, even when
running legal limit. I've put several clamps-ons on the problem tv. I
also have a cat5 and telephone cable coming out here to the shak
underground and have clamp-ons on them as well.
Where do I start?
Thanks ... 73 Dwight NS9I
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