On Thu, 10 Apr 2008 12:32:56 -0400, Bill Ames wrote:
>One time when I had a noise problem I used a pair of ferrite cores,
My tutorial on RFI and ferrites includes a section on using ferrite cores
to kill noise in mobile applications.
http://audiosystemsgroup.com/RFI-Ham.pdf
The "executive summary" is that while ferrites DO saturate when they see
enough DC, they don't see nearly as much DC on receive as they do on
transmit. So if you use sufficiently robust ferrites (that is, BIG) you can
knock down the noise coupled into the RX on the power wiring.
>one on each leg of the DC power into the rig.
Where are you getting your power? I've gone straight to the battery with
both + and -. W8JI says the neg should come from the frame of the motor.
It IS a good move to wind a bunch of turns of BOTH power leads through a
ferrite core. This will NOT saturate on transmit, and will kill common mode
noise back onto the car's DC system (which can get into one of the car's
computers and cause lots of grief).
73,
Jim Brown K9YC
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