>Does anyone know of the major sources of EI in a '93 or older dakota? I
>just installed a CB and noticed that the interference from the engine is
>near intolerable. I mounted the CB and antenna as far from the engine as I
>could but was surprised at how much it's picking up
>>what kind of cb is it?? some cheap ones will do that...
The antenna location relative to the engine isn't likely to make much
difference. You'll be best off mounting that smack in the center of the
roof, to get the best transmission pattern -- and take the time to tune
it to your radio with an SWR meter (or have a CB shop do it). There should
be instructions with your antenna.
I have a '93 Dak too, and there's a bit of ignition noise, but not too
bad, until my cap & rotor are due for replacement. Then, I get a hail
storm of ignition whine. Also - I was careful to tap the lighting circuit,
not the ignition, for power to the CB, and the ground is on the firewall
near where the engine is grounded to reduce any ground loops. If you
still have problems, I'd put a big (100 microfarad or larger) capacitor,
AND a small (0.01 uF) capacitor, in parallel across the power leads to
the CB, and you could add a ferrite slug (as from computer gear) between
where the capacitors are connected and the CB. The capacitors provide a
low-impedance path for radio frequency noise, and the ferrite bead will
act as an RF choke, without adding any DC resistance. If you still have
problems after that, you need new plug wires etc, or you're running
non-resistor plugs.
Cheap CB's are more susceptible to noise in the power supply than pricier
units. All modern CB's do a pretty fair job of filtering out-of-band
radio interference. Of course, if your ignition system isn't healthy, it
makes a pretty good spark-gap radio transmitter! And the reason those
are only permitted on the air is for Hamfests and historic demonstrations
is because they smear the spectrum with their signal.
If you have any other questions, email. We don't need to clutter the list
with radio (or political) gibberish.
Jim
"There is already a ban on ALL CRIME. It is not working." - Thomas Sowell
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