"Frank Gilliland" wrote in message
...
In , "Randy" wrote:

snip

Just so I am clear about one thing .... In all of these articles that I
have been reading, when they talk about grounding the antenna, they are
referring to a RF ground (ground plane) and not a physical ground? If for
some reason the shield is not grounded would this be my problem?


Close. Whine is RF interference from the engine electrical system (and
sometimes
other electrical devices like the fuel pump) and occurs on almost all
vehicles.
The difference is that an engine compartment which is fully enclosed by
metal
will shield the radio and coax from this noise (the noise can also pass
through
the electrical system, but that doesn't seem to be your problem). If you
have a
fiberglass hood, or if your coax passes through the engine compartment,
the coax
must be grounded at the radio end or it will pick up this noise just like
an
antenna.

An RF ground is both an electrical ground -and- a physical ground. It is a
low-impedance path for RF and is very dependent on the physical properties
of
the connection. Usually, a good RF ground is any point where electricity
can
easily take many different directions -- kinda like ****ing into a lake.
Just
about any point on the chassis will be a good RF ground. A single wire to
the
chassis is a better antenna than an RF ground. For example, if your radio
is
grounded with a wire longer than just a few inches it will allow RF
voltage to
develop on the radio chassis, and the radio effectively becomes part of
your
antenna system. That makes it very suseptible to engine noise and other
types of
RF interference that may be picked up by the coax shield (which is
connected
directly to your radio chassis) or passed through the electrical system to
your
power leads. So by RF grounding the radio (and therefore your coax) you
are
shunting all that RF interference to ground so the radio doesn't have to
deal
with it.

Not having a good RF ground at the antenna can screw up your SWR, but
that's
about all. It's much more important to ground that radio!


My boss will not care that this unit has a whine. I am not sure he would
care whether it has a CB or not. I had to take the truck down to the shop
last week to get the steer tires balanced, I had to pay for everything.
He
is not a bad guy ... just cheap!


If it's a business expense it should be paid for by the business.


The unit might not be grounded very good. It sits in an upper header
console, just strapped in not bolted. I will ground the unit and purchase
a
noise filter then adjust my antennas.


The upper header console is a terrible ground if your roof is fiberglass.
I
would recommend mounting it on the dash or the hump, close to the chassis.
That
will require rerouting the coax, but at this point that seems unavoidable.


I tried reading as many articles as I could but they all were saying
the
same things and some of that I could not understand. I thank you for your
time. I will let you know if the problem persist after these changes.

Thanks again





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Actually the header is aluminum and part of the cab, not bolted or riveted.
After working with it today I feel the alternator is the primary problem.
Since I have no ignition and no whine with the key in the ON position (Fuel
Pump), the alternator seems to be the culprit. I have been reading about
installing a micro_farad capacitor between the alternator and ground in
order to steady the voltage thus reducing the whine. I understand the theory
but could use some feedback about the practical application.

I feel this might be my least time consuming and least expensive solution.