You should be able to remove the plastic inserts where the antennas are
mounted. You may also have a problem with the splitter that allows the
stereo and TV to use the same antennas. Maybe you can use one antenna for
the CB and the other for everything else. As for the whine, I agree with
everyone else. Once the antennas are working properly, it may go away.

Chris
"Randy" wrote in message
...

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

snip
I thought that because the whine went away when I disconnected the coax
that
the problem was not related to the power supply and one of those noise
filters would not be of much use.


You said the noise is not present on your broadcast radio, which tells
me
that
the noise isn't coming from the antenna. If the noise goes away when you
disconnect the coax then it must be being picked up by the coax shield.
If
the
coax shield were grounded then the CB would not hear the noise. Since
the
coax
shield is connected to the chassis of the CB, that means the CB isn't
grounded
(by 'grounded' I mean an RF ground). The radio should be grounded by
mounting it
directly to the metal chassis and using a very short negative power
lead.
The
noise filter helps prevent noise from any possible ground-loops or other
RF
feedback paths.


My biggest obstacle is that this is a company truck. The CB, radio and
TV
are all using these antennas thru some kind of combiner.


.....yikes!


Running new coax
would mean drilling holes in the cab. I am not sure how my boss would
feel
about this. If it were my truck I would rip it all out and start from
scratch but I must do the best I can with what I have.


Your boss wants you to deliver the payload in the shortest amount of
time
with
the least amount of hassles. To do your job well, local communication
with
a
good CB is -extremely- helpful, and almost essential for a long-haul
driver.


The antennas are mirror mounts. I have been reading about grounding. I
thought that two antennas actually were better on the fiberglass
vehicles
because they could create a ground plane between each other. My
antennas
use
a plastic insert to keep them from being grounded to the mirrors. If I
ground them would this short out the transmitter?


Dual antennas have no practical advantage over a single antenna in a
mobile
installation. They do not create a ground plane between them, nor do
they
work
as a counterpoise to each other. They do look cool, but if I were you I
would
just use one and avoid the hassle.

As for the antenna mount, the shield of the coax should be -well-
connected to
the chassis (ground-plane), and the center conductor to the antenna. The
plastic
insert is used to keep the two apart. If you disconnect the coax at the
radio
and check it with an ohmmeter (center conductor to the shield), it
should
be
wide open; i.e, -not- shorted.


I appreciate your feedback Frank, I know that it is difficult to
diagnose
something from a distance but I am willing to try anything except
routing
new coax.


Don't spend -your- time or money -- convince your boss that you need a
CB
radio,
then get him to have his contracted radio shop do a proper installation.
That's
what most trucking companies do, and I'm suprised your's doesn't.




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?

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!

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.

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

"Chris" wrote in message
nk.net...
You should be able to remove the plastic inserts where the antennas are
mounted. You may also have a problem with the splitter that allows the
stereo and TV to use the same antennas. Maybe you can use one antenna for
the CB and the other for everything else. As for the whine, I agree with
everyone else. Once the antennas are working properly, it may go away.

Chris

If I remove the plastic inserts from the antenna mount, will that create a
direct short when I am transmitting?

I believe the splitter could be the problem also, like I said earlier if
this my truck I would rip it all out and start from scratch. I did a little
work ... swr @ 2.1. I just transmitted 9 miles. Whine still there ...
might be louder.

I am still wondering what is actually causing the whine i.e. alternator,
fuel pump ....... maybe I need to look at the source of the whine rather
than the ability to filter it out?

The mounting bracket should be grounded to the truck and attached to the
coax sheild. There SHOULD be an insulator between the antenna and the
bracket so leave it there.

Chris
"Randy" wrote in message
...

"Chris" wrote in message
nk.net...
You should be able to remove the plastic inserts where the antennas are
mounted. You may also have a problem with the splitter that allows the
stereo and TV to use the same antennas. Maybe you can use one antenna
for
the CB and the other for everything else. As for the whine, I agree with
everyone else. Once the antennas are working properly, it may go away.

Chris

If I remove the plastic inserts from the antenna mount, will that create
a
direct short when I am transmitting?

I believe the splitter could be the problem also, like I said earlier if
this my truck I would rip it all out and start from scratch. I did a
little
work ... swr @ 2.1. I just transmitted 9 miles. Whine still there ...
might be louder.

I am still wondering what is actually causing the whine i.e. alternator,
fuel pump ....... maybe I need to look at the source of the whine rather
than the ability to filter it out?