[RFI] RE: telephone system RFI

J. Bradshaw J. Bradshaw" <ac6tk@cybertime.net
Fri, 30 Jan 1998 14:10:41 -0800

Hello Jeff,

I don't know if this applies, but I had lots of trouble with my Tosh 486
laptop hanging up the phone line to my ISP every time I keyed the radio on
HF.  I suspected the trouble was RF getting into the X-jack pcmcia card via
the phone line.  After trying one of those split common mode ferrites and
shielding, etc., etc., I finally tried larger torroid cores.

Three turns of the phone line jumper (at the computer end) on an unknown
surplus torroid helped on most bands, but wasn't sufficient at 40 and 80m. 
I am using 5 turns on a slightly larger core now, and there is no trouble
at all.  You might just try more and more L with more turns or more
permeability until the trouble goes away.

I realize that your equipment probably wasn't designed for use in RF
fields.  Try focusing on the "antennas" going in and out of the units.

Jim Bradshaw, ac6tk@cybertime.net

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