Hare,Ed, W1RFI w1rfi@arrl.org
Thu, 23 May 2002 13:40:40 -0400

Cool!  Maybe you could consider writing this up and submitting it to QST
Hints and Kinks.  They will actually pay you a token amount! :-)  I can't
speak for the editor, but it looks like good information.

Ed Hare, W1RFI
225 Main St
Newington, CT 06111
Tel: 860-594-0318
Internet: w1rfi@arrl.org
Web: http://www.arrl.org/tis

> -----Original Message-----
> From: David Jordan [mailto:wa3gin@erols.com]
> Sent: Wednesday, April 17, 2002 9:35 AM
> To: rfi@contesting.com
> HI folks,
> I was getting some RFI on the sub-woofer of the Ford Sport Trac stereo
> from my 40m HF antenna mounted at the left rear of the truck bumper.
> The RFI would deminish when I stepped on the brakes so I 
> presumed I was
> getting RF pick-up on the wires feeding the rear brake lights.
> The bed of the Sport Trac is made from composite so there is no sheet
> metal to interfer with the antenna but also no sheet metal to 
> shield the
> wiring of the brake lights.
> I decided to place a few ferrite clam shells on the wires feeding the
> rear brake lights.  Well, the RFI to the sub-woofer dis-appeared.  The
> wires must have been picking up the HF signal and super-imposing it on
> the other wires in the wiring harness feeding the rear of the truck.
> The other wires included the dc power for the fuel tank pump and the
> sub-woofer, etc.
> To my surprise the noise from the fuel pump on the FT-900 transceiver
> has also dis-appeared.  Apparently, the fuel pump RFI was being
> super-imposed on the wires in the harness and re-radiating along the
> wires all the way back to the location of the antenna, where it was
> picked up by the 40m HF antenna and fed to the FT-900.
> Who would have thunk it,
> dave
> wa3gin
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