FT-240-43 works for most HF and VHF applications, for the lower end of HF and
BCB use FT-240-77. Same size, different mix. They're not cheap ($9.00 each),
but they cure heavy duty problems that nothing else will touch. I fixed some
nasty RFI in the 5.1 Surround Sound system in the family room that was getting
wrecked on 20 meters. I tried clamp on beads, bypass caps and RFI filters on
the AC and nothing worked. So I wrapped several turns of each speaker lead
(there are 7 speakers, including the rear-center and sub-woofer), the power
cable and the coax from the cable company onto FT-240-43 cores, and that fixed
it. Not a single bit of RFI, no matter what band or power I run or how close
you listen to the 5.1 speakers.
I use the same ones on the mic input to the W2IHY 8-Band and the headphones
wire to the O2. A cheap surplus clamp-on worked on the CW paddles wire, but
the RFI was very slight there to begin with. The torroids will also clean up
RF that gets down the rotator cable and bothers older Telex rotator boxes when
you light up a kW inverted V or sloper on the tower.
Ron N6AHA
----- Original Message -----
From: Kc9cdt@aol.com
To: ronc@sonic.net
Sent: Monday, March 20, 2006 1:01 PM
Subject: Re: [TenTec] RF Getting back into Rig Problem
Ron,
Which particular ferrites from Amidon are you using?
Part Nmber if you have it handy would also help out.
I need a few!
Thanks,
Lee
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