[aprssig] APRS (Fire) In A Car

Curt, WE7U archer at eskimo.com
Tue Jan 24 10:42:03 EST 2006

On Tue, 24 Jan 2006, Wes Johnston wrote:

> If you want to protect your radio from car starting, put a 20A fuse in
> the neg lead of the radio.  Of course another solution is to run the
> negative lead of the radio to the - battery terminal and don't ground
> your rig to the car chassis.

However, your antenna will usually provide that ground, so trying to
isolate your radio from the car chassis won't work unless you're
using some sort of fiberglass boat antenna that doesn't need a

I've had similar trouble to that described, twice, years ago.  Both
instances can be attributed to not fusing the ground lead from the
radio.  In both cases a wire got so hot as to burn off all the
insulation, filling the cars with smoke.  No fires resulted but
easily could have.  In fact my parents car was disabled from this as
the hot wire burned into a bundle of other wires.  I can be thankful
I had understanding parents (I was in high school at the time).

I'll keep that wire-too-small-to-blow-fuse thing in mind too, that's
good advice.  Another good piece of advice that came across is to
check your grounding straps from the engine to the chassis, battery
to chassis.  I suspect that both times when I had trouble it was due
to poor grounding in the cars:  The starting current tried to go
through the radio.  All the smoke was let out while starting the

Curt, WE7U.   APRS Client Comparisons: http://www.eskimo.com/~archer
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