[TenTec] RF Getting back into Rig Problem

[Ron Castro]

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 at aol.com 
  To: ronc at 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