K7AAY wrote:
With a Yaesu VX-5 powered from a Radio Shack car cord attached to the
console cigar lighter socket, I get rapidly repeating noise likened by
others to spark plug noise; but, no spark plugs on a diesel. Removing
the card cord and transmitting on battery eliminates the problem.

I'm about to switch from the VX-5 HT to a Kenwood TM-V7A; how may I
avoid this problem when installing the mobile transceiver.


Thank you in advance for your on-topic suggestions.

73s & best regards,

K7AAY


Fuel injectors are the most likely source of the noise.

First, use a direct connection to the battery terminals. Second, twist the
connecting wires 2 or 3 twists per foot from the battery to your radio. Third,
get a GOOD chassis ground connection for the radio.

If noise persists talk with the CRD service techs regarding slightly slowing
down the rise time of the fuel injectors or adding a suppression diode across
the fuel injector coils [it is unlikely you will get any support in this area,
but worth a try]