[TenTec] RF gets into computer

John T. Fleming W3GQJ at earthlink.net
Thu Oct 26 10:23:45 EDT 2006


I used to have trouble with a CO detector going off then I was on 20 meters.
The resolution was to route the A/C power lead differently.  Try a keyboard
that plugs into the keyboard socket instead of the USB port.  Also pick up a
ferrite power cord donut that splits in half and see if wrapping several
turns of the computer cord eliminates the signal from the 80 meter antenna.

Years ago a friend had trouble when he operated 75 meters AM running 1 KW.
His neighbors attic lights would turn on from the picked up RF energy!  It
took a while before they realized that the ham neighbor was "turning on and
off" the light.


-----Original Message-----
From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
On Behalf Of John K Gotwals
Sent: Thursday, October 26, 2006 9:56 AM
To: tentec at contesting.com
Subject: [TenTec] RF gets into computer

When I operate on 75 meter SSB with my Orion, my computer beeps and 
disconnects/reconnects my USB connected keyboard. Note that I do not have 
this problem on 40 meter SSB. My computer is located on the second floor of 
a brick house, and one end of my dipole is about 15 feet from my shack.

>From comments made by others on this list, I may have to put RF filters on 
the cables and wires connected to my computer. I am contemplating the use of

Amidon FT-240-77 ferrite toroids, which have an I.D. of 1.4 inches and cost 
$9 each. If I buy in quantities of 10, is there a cheaper source for this 

Any comments or suggestions on this problem would be appreciated. 

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