> Whenever I transmit my tacho goes off the scale - obviously an RF issue - it
> goes back again when I stop transmitting. I thought about replacing the wires
> to the tacho with shielded wires but thought why not simply wrap aluminum
> foil/tape around them. I probably wouldn't earth the tape.
>
> Do you think this would do anything to help?
From my fiddling with this stuff using a handheld comm, there seems no
rules for these problems. It depends upon the nature of the circuit
affected, length of wiring involved vs. frequency, and even its
orientation (polarization).
I think not grounding the foil is least likely a fix and would start by
grounding at the engine end before other permutations. A shielded
twisted pair may also work better. It also may not be the signal wire
at all. So other approaches are a small capacitor (say .1uf) across
ground and and 14V at the instrument. Try running the ground wire to a
different place; try making 14V and ground a twisted pair.
Regards,
Fred F.
|