Antenna Whine?
 

I drive a 9900 International. I am getting a loud whine in the CB speaker,
but not in the radio speakers, even though they share the dual antennas. The
whine increases and decreases with the rpms of the motor. After
disconnecting the coax from the CB transceiver the whine is gone. Does this
mean the coax or antennas are definitely the problem? ... or are they just
picking up on a problem with the alternator? The coax will be extremely hard
to replace, maybe impossible since this is a company truck. The alternator
would probably be easier to repair.

Any help to eliminate or even reduce the whine would be greatly appreciated.

"Randy" wrote:
I drive a 9900 International. I am getting a loud whine in the CB
speaker, but not in the radio speakers, even though they share the dual
antennas. The whine increases and decreases with the rpms of the motor.
After disconnecting the coax from the CB transceiver the whine is gone.
Does this mean the coax or antennas are definitely the problem? ... or
are they just picking up on a problem with the alternator? The coax will
be extremely hard to replace, maybe impossible since this is a company
truck. The alternator would probably be easier to repair.

Any help to eliminate or even reduce the whine would be greatly
appreciated.

Sounds like not enough ground on your antenna. How's your swr?

--
http://www.allpar.com/mopar.html

In , "Randy" wrote:

I drive a 9900 International. I am getting a loud whine in the CB speaker,
but not in the radio speakers, even though they share the dual antennas. The
whine increases and decreases with the rpms of the motor. After
disconnecting the coax from the CB transceiver the whine is gone. Does this
mean the coax or antennas are definitely the problem? ... or are they just
picking up on a problem with the alternator? The coax will be extremely hard
to replace, maybe impossible since this is a company truck. The alternator
would probably be easier to repair.

Any help to eliminate or even reduce the whine would be greatly appreciated.


What brand/model radio are you using?





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"Steveo" wrote in message
...
"Randy" wrote:
I drive a 9900 International. I am getting a loud whine in the CB
speaker, but not in the radio speakers, even though they share the dual
antennas. The whine increases and decreases with the rpms of the motor.
After disconnecting the coax from the CB transceiver the whine is gone.
Does this mean the coax or antennas are definitely the problem? ... or
are they just picking up on a problem with the alternator? The coax will
be extremely hard to replace, maybe impossible since this is a company
truck. The alternator would probably be easier to repair.

Any help to eliminate or even reduce the whine would be greatly
appreciated.

Sounds like not enough ground on your antenna. How's your swr?

--
http://www.allpar.com/mopar.html


swr is ~ 3

I am just learning about CB radios. I know the antennas are using plastic
inserts to keep them from being grounded.
I am using Firestik II antennas and have not tried adjusting them yet. I
thought I needed to eliminate the whine first.
This International has a fiberglass top making for a bad ground plane, from
what I have been reading.

That is about all I know of my situation.

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

I drive a 9900 International. I am getting a loud whine in the CB
speaker,
but not in the radio speakers, even though they share the dual antennas.
The
whine increases and decreases with the rpms of the motor. After
disconnecting the coax from the CB transceiver the whine is gone. Does
this
mean the coax or antennas are definitely the problem? ... or are they
just
picking up on a problem with the alternator? The coax will be extremely
hard
to replace, maybe impossible since this is a company truck. The
alternator
would probably be easier to repair.

Any help to eliminate or even reduce the whine would be greatly
appreciated.


What brand/model radio are you using?




I am using a Cobra 29 NW right out of the box.

Antennas are 4' Firestiks II

swr ~ 3

"Randy" wrote:
I am using a Cobra 29 NW right out of the box.

Antennas are 4' Firestiks II

swr ~ 3

swr - 3? you got problems and dual antenna's suck. Try using
just one of them.

--
http://www.allpar.com/mopar.html

"Randy" wrote:
"Steveo" wrote in message
...
"Randy" wrote:
I drive a 9900 International. I am getting a loud whine in the CB
speaker, but not in the radio speakers, even though they share the
dual antennas. The whine increases and decreases with the rpms of the
motor. After disconnecting the coax from the CB transceiver the whine
is gone. Does this mean the coax or antennas are definitely the
problem? ... or are they just picking up on a problem with the
alternator? The coax will be extremely hard to replace, maybe
impossible since this is a company truck. The alternator would
probably be easier to repair.

Any help to eliminate or even reduce the whine would be greatly
appreciated.

Sounds like not enough ground on your antenna. How's your swr?

--
http://www.allpar.com/mopar.html

swr is ~ 3

I am just learning about CB radios. I know the antennas are using
plastic inserts to keep them from being grounded.
I am using Firestik II antennas and have not tried adjusting them yet.
I thought I needed to eliminate the whine first.
This International has a fiberglass top making for a bad ground plane,
from what I have been reading.

That is about all I know of my situation.

There's no stupid questions, Randy. The first thing to make sure of
is your antenna, it's just like any other electrical connection
and it has to be right. Good ground and swr and separation from
the body metal just for starters.

Some of that noise can be from the electric fuel pump on certain
vehicles. Get your swr down to 1.5 or less for starters.

You'll have to process of eliminate for any static after you know
your antenna is working properly. They do sell filters for some
of that noise, it goes on your hot lead.

Longer is better for antenna's..you can un-screw it without
getting out of the truck if you mirror mount it.

--
http://www.allpar.com/mopar.html

In , "Randy" wrote:


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

I drive a 9900 International. I am getting a loud whine in the CB
speaker,
but not in the radio speakers, even though they share the dual antennas.
The
whine increases and decreases with the rpms of the motor. After
disconnecting the coax from the CB transceiver the whine is gone. Does
this
mean the coax or antennas are definitely the problem? ... or are they
just
picking up on a problem with the alternator? The coax will be extremely
hard
to replace, maybe impossible since this is a company truck. The
alternator
would probably be easier to repair.

Any help to eliminate or even reduce the whine would be greatly
appreciated.


What brand/model radio are you using?




I am using a Cobra 29 NW right out of the box.

Antennas are 4' Firestiks II

swr ~ 3


Your SWR is high. High SWR isn't responsible for whine, but it is a good
indicator of other problems. From what you said in your other post your cab roof
is fiberglass, so you don't have any ground plane -at all- for your antenna. But
even that isn't responsible for the whine. I suspect that the radio isn't very
well grounded. The mounting bracket should be bolted directly to the dash or
some other chassis metal, and the negative power lead should be as short as
possible (inches) to the same. You can also try a noise filter on your positive
power lead, and tap the wire as close to the radio as possible. That should
eliminate your whine. It should also get your SWR down below 3.

As for your antenna, you need to find a point on the rig where the antenna can
be mounted directly to the chassis. A mirror mount is ok if the bracket and door
are well grounded. A 9' whip on the front bumper isn't a bad choice either
(don't forget to tie it back a bit so it doesn't flop around). You could also
try one of those 'no-ground-plane' antennas but don't expect great results. Ask
around the watering holes and see what others have done.





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"Steveo" wrote in message
...
"Randy" wrote:
I am using a Cobra 29 NW right out of the box.

Antennas are 4' Firestiks II

swr ~ 3

swr - 3? you got problems and dual antenna's suck. Try using
just one of them.

--
http://www.allpar.com/mopar.html

I had this same setup on another truck of the same year and model without
any whine. That setup also had a fairly high swr but zero whine.

Are you suggesting that because I have high swr that this is somehow
allowing this whine to be picked up by the antennas? .. or maybe causing the
whine? What is actually causing the whine?

"Randy" wrote:
"Steveo" wrote in message
...
"Randy" wrote:
I am using a Cobra 29 NW right out of the box.

Antennas are 4' Firestiks II

swr ~ 3

swr - 3? you got problems and dual antenna's suck. Try using
just one of them.

--
http://www.allpar.com/mopar.html

I had this same setup on another truck of the same year and model
without any whine. That setup also had a fairly high swr but zero whine.

Are you suggesting that because I have high swr that this is somehow
allowing this whine to be picked up by the antennas? .. or maybe causing
the whine? What is actually causing the whine?

I'm suggesting perhaps your transmitting off just your coax, with your
swr being 3. Start with your antenna problems, then fix the whine.

--
http://www.allpar.com/mopar.html