[SEDXC] UHF TVI

[Ed Tanton]

I have been asked, as the ARRL's (GA) Technical Coordinator, to look 
into a case of TVI. Here is what I have replied to our GA SCM:
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The 'victim' is a very nice guy-not being the least bit grumpy. There 
are some interesting things about his problem, but I don't think it's 
going to be a ham causing it. The problem is UHF only. Starts about 
CH46. Nothing on VHF at all. I asked him to try and record it for me, 
and told him I would be happy to come look at everything, and see if 
I have any ideas. They do not watch all that much TV, and that's why 
they do not have cable. Still, it sounds like the interference just 
happens to be on channels he does want to watch.

I gave him both my TEL# and email address. I reinforced my interest 
in his problem, and told him I was only interested in solving 
it-regardless of what-or who-is at fault.

This problem only occurs at night (or, they may not really have 
noticed it in the daytime.) It is irregular, consisting of picture 
disruption and sound noise. He did indeed get a new TV, and this has 
been going on for years. He has an indoor (attic) TV antenna, with 
not much more than 30ft of coax. He thinks he grounded the antenna to 
a water-pipe ground. As I mentioned, he's going to try and record 
some of it-though it is clearly not (he said) Morse code-and 
otherwise, the best we will be able to tell would be if there's any 
audible signal ID possible-such as speech or digital signal products.

Very interesting! I explained that it did not sound like it was a 
ham, but that didn't matter to me at all-that I would do whatever I 
could to help him. I'll let you know what I learn.

I may try building him a UHF bandpass filter for starters. Initially, 
I'm thinking some sort of nearby commercial installation mixer 
product-but he said there were no hill/mountain-top antenna clusters 
nearby; no TV, police or fire stations; nor any cell-towers. 
Regardless, I'll see what can be done about it.
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If any of you have any suggestions, I would certainly welcome them.


Ed Tanton

website: http://www.n4xy.com

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