[RFI] Noise

[Hare,Ed, W1RFI]

If the noise manifests itself as a buzzy signal about every 15.75 kHz, for
antenna connected TVs, try a high pass filter at the TV set and a
common-mode choke (about 10 turns of the TV feed line onto a Palomar
F-240-43 core) on the feed line and a similar choke if necessary on the TV's
ac line cord.  For cable connected TVs, the high-pass filter is not needed. 

If the noise is a broadband hash, it is probably coming from a switch-mode
power supply.  In that case, try an ac-line filter (Radio Shack catalog
#15-1111 or Industrial Communications Engineers - see
http://www.arrl.org/tis/tisfind.html) first, and the common-mode chokes
second.

73,
Ed Hare, W1RFI

-----Original Message-----
From: kmarch [mailto:kmarch@ix.netcom.com]
Sent: Monday, October 16, 2000 9:01 PM
To: rfi@contesting.com
Subject: [RFI] Noise



One of the noises I have tracked down is coming from a TV set of my
neighbors.  I will have to quiet the radiation from it on the 160M ham band.
Anyone have any dood recommendations of how to keep the RF confined to the
set when it of course has other things connected to it, like outside
antennas?
    BTW.  I found one strong noise source eminating from a new Gateway
Computer monitor located about 1000 feet from my QTH.  A power line filter
cleaned it up nicely. One down. 5 to go.  Bob
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