"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.

--
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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

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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Frank Gilliland wrote:
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).

Don't see many of those in these parts, but it might work.

--
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In , Steveo
wrote:

Frank Gilliland wrote:
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).

Don't see many of those in these parts, but it might work.


It's not real popular, but I'm seeing it more and more -- probably due to the
increasing number of plastic tractors on the road.





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Frank Gilliland wrote:
In , Steveo
wrote:

Frank Gilliland wrote:
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).

Don't see many of those in these parts, but it might work.

It's not real popular, but I'm seeing it more and more -- probably due to
the increasing number of plastic tractors on the road.

See any on pickup trucks yet?

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

In , Steveo
wrote:

Frank Gilliland wrote:
In , Steveo
wrote:

Frank Gilliland wrote:
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).

Don't see many of those in these parts, but it might work.

It's not real popular, but I'm seeing it more and more -- probably due to
the increasing number of plastic tractors on the road.

See any on pickup trucks yet?


Just on the back bumper, and not too many of those. Seems everyone is so
paranoid about resale value these days that they are afraid to drill holes even
in the bumper. My Dodge has a 9' whip mounted dead center on the roo-guard right
above the winch, but I'm strange that way.




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Frank Gilliland wrote:
In , Steveo
wrote:

Frank Gilliland wrote:
In , Steveo
wrote:

Frank Gilliland wrote:
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).

Don't see many of those in these parts, but it might work.

It's not real popular, but I'm seeing it more and more -- probably due
to the increasing number of plastic tractors on the road.

See any on pickup trucks yet?

Just on the back bumper, and not too many of those. Seems everyone is so
paranoid about resale value these days that they are afraid to drill
holes even in the bumper. My Dodge has a 9' whip mounted dead center on
the roo-guard right above the winch, but I'm strange that way.

They don't call em' power-wagons for nothing! I had one on the
back of my gmc for a little while, but it turned out to be a
pain in the ass, so I went to a center roof mount Wilson. I
can reach and un-screw it if I need to. It handles 300 watts
nicely.

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