Appreciate what was said about wire. The battery ground and
radio ground may be same to 12 volts DC. But they are
completely different to RF - your static noise. Grounding the
antenna to the battery would only worsen the problem.
Grounding the antenna to the battery suggests you are not
learning the underlying principles posted by others. Battery
ground and radio ground are different - as far as the antenna
is concerned.

Antenna ground must be to radio ground. A previous post
also about how coax ground wire must not contact other ground
such as chassis was making the same point. The radio ground
is connected to ground directly at the base of the antenna -
for same reason. And again, the antenna coax wire connector
may 'look' connected to radio antenna socket - and yet still
not be connected.

Even possible that the antenna socket inside the radio has a
cracked solder joint - therefore the antenna ground is not
connected to radio.

Again, you still have not specifically listed what is
installed from factory and what is after market - only making
it more difficult for every reply to be helpful. Where did
that amp come from? How is it grounded?

Of course you already have the Jeep's wiring diagram. You
cannot be locating this problem (easily) without a wiring
diagram.

For example, along with what hrhofmann posted: is it an
electric fuel pump? Fuel pump is not always on. You should
have learned that by now in you search for the noise source.
For example, pump often turn on only for a few seconds after
key goes to on. Then if no engine requirement for fuel, the
electric fuel pump turns off. Does the noise go on and off
with fuel pump?

Pull the fuse that is only for alternator regulator. Does
noise disappear? Same for engine computer. To accomplish
anything from this trick, again, that wiring diagram is
necessary since even some disconnects may not fully remove
power as you assume. You cannot assume anything. The vehicle
has many computers - not just an engine computer. Any one
could be a noise source. Vehicle has something like 50
motors. Which motor is always on only when noise is created.

The transistor radio idea also works as long as you don't
assume a linear relationship between volume of noise on radio
and amplitude of noise. You have not even told us if noise is
radiated, if it is common mode, or if it is differential mode
on AC wires. Just another part of breaking the problem down
into parts.

Don't even try to fix anything. You are too far away from
even considering a solution. As hrhofmann posted, "once you
find the trouble, it will be obvious what is going on."
Again, break the problem down into parts. Your only concern
first is 'source of the noise'. You don't even know if the
noise is radiated or carried via 12 volt wires. Any attempt
to solve a problem with your current 'no information' is
equivalent to spinning tires in quicksand. Your only concern
is to identify the noise or its incoming path - not solve it.
Trying to solve it would only make the problem more difficult.

wrote:
Since my last post, I have tried a number of things to try to isolate
the issue. I connected a new (non-electric) antenna, and grounded it
directly to the battery. I had the radio on w/lots of static and pulled
each fuse (including fuel pump) one by one. I had a jumper cable on the
battery ground and conected it to the alternator, engine computer,
sound amp and radio ground itself.

None of these made any improvement.

I'll try grounding the fuel pump as I could not easily locate it
yesterday.

As to other questions posted here...nothing else in the vehicle seems
to correlate with less or more static. But it is worse sometimes than
others. Which may be a result of the weather or other conditions making
for a better or worse ground connection somewhere.

I'll keep tyring!