[TenTec] Low Pass Filter

JAMES HANLON knjhanlon at msn.com
Tue May 20 19:04:08 EDT 2008


Doug,

Wow, if I understand you correctly your neighbor is experiencing TVI from a 160 meter station that is 70 miles away.  That is, to say the least, very unusual.  I also understand that your 160 meter signal gets into her set, but not into yours.

My best guess is that it is a case of the 160 meter signal, which is within the passband of the video amplifier in the TV set, getting in directly to that video amplifier.  

That could be a difficult problem to correct for your own transmitter where the 160 meter signal is strong in the vicinity of the set.  You might try a "wavetrap," a series tuned circuit resonant at your 160 meter frequency, placed directly across the antenna terminals of the TV set.  When it is tuned to the frequency of the offending signal it will present a very low impedance to that signal and "short it out" so to speak.  The problem is that it may effect the TV signal as well, but nothing ventured, nothing gained.  It's likely that the wiring inside of the TV set itself is enough to pick up your nearby signal, but you might at least be able to attenuate the signal coming from north of Belfast with a trap like that.  

Have you considered trading TV sets with your neighbor so that she could watch her programs while you are on the air?

Jim, W8KGI



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