Re: CB radio noise (No Audi stuff)

["Kurt Wesseling" <kwessel@enm.maine.edu>]

> Try a SWR meter sold at a RADIO CRAP "shack", to match your annt to your
> radio.
> 
> Chewy
> FCC aproved
> 

Beg to differ with these suggestions.  Matching the antenna to the 
load will do virtually nothing to eliminate electrical noise.

Instead, determine where the noise is coming from.  If it is line (DC 
power) noise, you will still have it when the antenna is 
disconnected.  If that's the case an inline (series) inductive filter 
(coil) on the positive lead and an electrolytic capacitor across 
(parallel positive to negative, red to black) may reduce the noise.  
you can get these at rat shack, as well.

If the noise is much worse with the antenna connected, that's a 
tougher problem to resolve.  Make sure you are using resistive spark 
plugs for noise supression, and that you have no loose metal to metal 
connections in the engine compartment or anwhere else.  Even loose 
muffler and exhaust connections can generate considerable electrical 
noise.

With the engine running, turn the radio on and note the noise level.
Now, get out and lift the hood.  Is the noise worse?  If so, most of
your noise is probably coming from under the hood.  If not, it may be
coming from somewhere else.  

If you have enough antenna lead, you can sit in the car (while it is
running) and have a friend walk around the car holding the antenna a
foot or two away from the car taking note of where the noise is
worst.  I suspect it will be worst at the front of the car,
especially if the hood is open.

There are other things that can be done, but suggest you try these 
first.  BTW, you  _should_ match your antenna with an SWR meter.  Try 
for a match of 1.5:1 or better.  That will improve your transmission 
efficiency, but *not* lower noise.

--Kurt
1987 5KCSTQ



______________________________
Kurt Wesseling
Technical Support Center
The Education Network of Maine
800-696-4357
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