[TowerTalk] Station Ground

[Tom Rauch]

> The classic example is a mobile rig, with the -12V wire
going to the
> battery, and the rig grounded to the car chassis at some
point via the
> antenna coax. The chassis bonding  gets corroded, so now
there's a
> potential difference between parts of the chassis due to,
for instance,
> headlights or starter.  The radio becomes a low impedance
connection
> between the two parts of the chassis.

Headlights aren't that high in current.

Starters and alternators ALWAYS ground to the engine block,
as does the battery.

Vehicle chassis are almost always unibody.

You can avoid ANY issue with a ground by ground the radio to
the chassis and NOT the battery. Grounding to the battery
post is dumb.

Houses generally don't have a battery, alternator,
headlights, and starters. If they do, the real solution is
proper wiring, not adding ground resistance.


> There are also scenarios where the starter motor has an
explicit ground
> wire that comes loose.  Likewise, the alternator.

Not true. Alternators and starters NEVER have ground wires.
They are commoned to the engine block via mounting brackets,
and the battery high current lead is grounded to the block.

Bad wiring techniques are not corrected by installing an
intentionally bad ground. After all, radios require
feedlines and the shield is BIG and it should be well
grounded.

73 Tom