A little help...CB Install
 

I installed a CB in my Jeep Rubicon for use when my buddies and I go trail
riding. I mounted a *ahem* 48" Radio Shack fiberglass whip on a right angle
antenna mount directly to the rear bumper. I ran a 20' Radio Shack 50 ohm
cable from the antenna to the transmitter mounted under the seat (Cobra 75
WX ST).
Power is supplied by a 4 ga. wire directly from the battery. I scraped off
paint under one of the seat mounting brackets and bolted the wire to that to
get a good ground.

The problem I'm having is calibrating the SWR meter. When key and hold down
the mic, I turn the meter's calibration knob all the way to the right and
the needle is still short of the calibration mark.

Any suggestions would be greatly appreciated.

Rob Kulp

In , "Rob"
wrote:

I installed a CB in my Jeep Rubicon for use when my buddies and I go trail
riding. I mounted a *ahem* 48" Radio Shack fiberglass whip on a right angle
antenna mount directly to the rear bumper. I ran a 20' Radio Shack 50 ohm
cable from the antenna to the transmitter mounted under the seat (Cobra 75
WX ST).
Power is supplied by a 4 ga. wire directly from the battery. I scraped off
paint under one of the seat mounting brackets and bolted the wire to that to
get a good ground.

The problem I'm having is calibrating the SWR meter. When key and hold down
the mic, I turn the meter's calibration knob all the way to the right and
the needle is still short of the calibration mark.

Any suggestions would be greatly appreciated.

Rob Kulp


Could be lots of things. First, check the radio and antenna on a friend's
vehicle to make sure they work. Check the coax to make sure there isn't a short
from the center conductor to the shield. Check the entire length of the coax to
see if there are any nicks, crimps or sharp bends. If so, or if you are using
foam coax (RG-xx/F), throw it away and get some good stuff. Wind your excess
coax in a figure-8, not a loop. Keep your ground lead as short as possible. Make
sure the antenna mount isn't shorted. Check your SWR meter to make sure you have
it set for the correct range. The meter could be bad, so test your installation
with a different meter. Check your DC voltage at the radio when you key up -- if
the voltage drops you might have a weak connection somewhere.

If all that fails to reveal the problem, seek a local expert.







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"Rob" wrote in message
om...
I installed a CB in my Jeep Rubicon for use when my buddies and I go trail
riding. I mounted a *ahem* 48" Radio Shack fiberglass whip on a right
angle
antenna mount directly to the rear bumper. I ran a 20' Radio Shack 50 ohm
cable from the antenna to the transmitter mounted under the seat (Cobra 75
WX ST).
Power is supplied by a 4 ga. wire directly from the battery. I scraped off
paint under one of the seat mounting brackets and bolted the wire to that
to
get a good ground.

The problem I'm having is calibrating the SWR meter. When key and hold
down
the mic, I turn the meter's calibration knob all the way to the right and
the needle is still short of the calibration mark.

Any suggestions would be greatly appreciated.

Rob Kulp


Have you hooked up an actual swr
meter? If so, what was it's reading?

Landshark


--
Hard things are put in our way,
not to stop us, but to call out our
courage and strength.

On Tue, 30 Mar 2004 01:07:55 GMT, "Rob" wrote:

I installed a CB in my Jeep Rubicon for use when my buddies and I go trail
riding. I mounted a *ahem* 48" Radio Shack fiberglass whip on a right angle
antenna mount directly to the rear bumper. I ran a 20' Radio Shack 50 ohm
cable from the antenna to the transmitter mounted under the seat (Cobra 75
WX ST).
Power is supplied by a 4 ga. wire directly from the battery. I scraped off
paint under one of the seat mounting brackets and bolted the wire to that to
get a good ground.

The problem I'm having is calibrating the SWR meter. When key and hold down
the mic, I turn the meter's calibration knob all the way to the right and
the needle is still short of the calibration mark.

Any suggestions would be greatly appreciated.

If an SWR meter will not calibrate, there are 3 common reasons for
this (and a whole list of uncommon ones).
The first is an obvious lack of transmitter power. If your radio isn't
putting out at least a watt or 2, chances are you won't be able to
calibrate the meter.

The second is a radical fault in the antenna/feedline system. If the
cable or antenna mount is shorted, it can prevent the meter from
calibrating. One way to check this is to switch to the SWR position.
If the meter stays at the same point, you have a short.

The third common reason is a simple one. Is the meter hooked up
backwards? If you reverse the input and output connections, the meter
will not work properly, and you are actually trying to calibrate on
the reflected power (Which should be low). Again, a check for this
would be to switch to the SWR position. If the meter now pegs hard,
chances are you have it backwards.

Oh, and I just thought of a 4th reason. Are you sure you're on the
calibrate position?

Dave
"Sandbagger"
http://home.ptd.net/~n3cvj

On Tue, 30 Mar 2004 01:07:55 GMT, "Rob" wrote:

I installed a CB in my Jeep Rubicon for use when my buddies and I go trail
riding. I mounted a *ahem* 48" Radio Shack fiberglass whip on a right angle
antenna mount directly to the rear bumper. I ran a 20' Radio Shack 50 ohm
cable from the antenna to the transmitter mounted under the seat (Cobra 75
WX ST).
Power is supplied by a 4 ga. wire directly from the battery. I scraped off
paint under one of the seat mounting brackets and bolted the wire to that to
get a good ground.

The problem I'm having is calibrating the SWR meter. When key and hold down
the mic, I turn the meter's calibration knob all the way to the right and
the needle is still short of the calibration mark.

Any suggestions would be greatly appreciated.

Rob Kulp


First check what Frank and Dave suggested, then try this:

(hopefully your antenna is one of Radio Shacks adjustable ones)

1. Find out which channel gives you the lowest forward calibration
reading (1 or 40)

2. Note that reading

3. flip the switch to check the reverse reading.

4. Note that reading.

5. Change to the channel that gave you the highest forward calibration
reading.

6. Adjust the reading to same level as step 2.

7. flip the switch to check the reverse reading.

8. This will give you a "relative" SWR reading.

9. Depending on which channel gave you the lowest "relative" reading:
If your lowest reading was on channel 1, your antenna is too long.
If your lowest reading was on channel 40, your antenna is
too short.

Adjust your antenna.

On Tue, 30 Mar 2004 13:48:06 GMT, Lancer wrote:

On Tue, 30 Mar 2004 01:07:55 GMT, "Rob" wrote:

I installed a CB in my Jeep Rubicon for use when my buddies and I go trail
riding. I mounted a *ahem* 48" Radio Shack fiberglass whip on a right angle
antenna mount directly to the rear bumper. I ran a 20' Radio Shack 50 ohm
cable from the antenna to the transmitter mounted under the seat (Cobra 75
WX ST).
Power is supplied by a 4 ga. wire directly from the battery. I scraped off
paint under one of the seat mounting brackets and bolted the wire to that to
get a good ground.

The problem I'm having is calibrating the SWR meter. When key and hold down
the mic, I turn the meter's calibration knob all the way to the right and
the needle is still short of the calibration mark.

Any suggestions would be greatly appreciated.

Rob Kulp


First check what Frank and Dave suggested, then try this:

(hopefully your antenna is one of Radio Shacks adjustable ones)

1. Find out which channel gives you the lowest forward calibration
reading (1 or 40)

2. Note that reading

3. flip the switch to check the reverse reading.

4. Note that reading.

5. Change to the channel that gave you the highest forward calibration
reading.

6. Adjust the reading to same level as step 2.

7. flip the switch to check the reverse reading.

8. This will give you a "relative" SWR reading.

9. Depending on which channel gave you the lowest "relative" reading:
If your lowest reading was on channel 1, your antenna is too long.
If your lowest reading was on channel 40, your antenna is
too short.

Adjust your antenna.

And if this works as described, when you are done, take your radio to
a local tech to determine why your power out is so low....

Dave
"Sandbagger"
http://home.ptd.net/~n3cvj

I hate to admit it, but the meter was hooked up backwards.
Thank you for the help.

On another note, on channel 1 my SWR is 2 and on channel 40 it's 3. The
antenna is a 48" Fiberglass whip from Radio Shack and is adjustable. I'm
guessing that I need to shorten the antenna?

Thanks again,

Rob Kulp

"Dave Hall" wrote in message
...
On Tue, 30 Mar 2004 01:07:55 GMT, "Rob" wrote:

I installed a CB in my Jeep Rubicon for use when my buddies and I go
trail
riding. I mounted a *ahem* 48" Radio Shack fiberglass whip on a right
angle
antenna mount directly to the rear bumper. I ran a 20' Radio Shack 50 ohm
cable from the antenna to the transmitter mounted under the seat (Cobra
75
WX ST).
Power is supplied by a 4 ga. wire directly from the battery. I scraped
off
paint under one of the seat mounting brackets and bolted the wire to that
to
get a good ground.

The problem I'm having is calibrating the SWR meter. When key and hold
down
the mic, I turn the meter's calibration knob all the way to the right and
the needle is still short of the calibration mark.

Any suggestions would be greatly appreciated.

If an SWR meter will not calibrate, there are 3 common reasons for
this (and a whole list of uncommon ones).
The first is an obvious lack of transmitter power. If your radio isn't
putting out at least a watt or 2, chances are you won't be able to
calibrate the meter.

The second is a radical fault in the antenna/feedline system. If the
cable or antenna mount is shorted, it can prevent the meter from
calibrating. One way to check this is to switch to the SWR position.
If the meter stays at the same point, you have a short.

The third common reason is a simple one. Is the meter hooked up
backwards? If you reverse the input and output connections, the meter
will not work properly, and you are actually trying to calibrate on
the reflected power (Which should be low). Again, a check for this
would be to switch to the SWR position. If the meter now pegs hard,
chances are you have it backwards.

Oh, and I just thought of a 4th reason. Are you sure you're on the
calibrate position?

Dave
"Sandbagger"
http://home.ptd.net/~n3cvj

Don't buy Rat Shack junk!
Dave!

On Tue, 30 Mar 2004 01:07:55 GMT, "Rob" wrote:

I installed a CB in my Jeep Rubicon for use when my buddies and I go trail
riding. I mounted a *ahem* 48" Radio Shack fiberglass whip on a right angle
antenna mount directly to the rear bumper. I ran a 20' Radio Shack 50 ohm
cable from the antenna to the transmitter mounted under the seat (Cobra 75
WX ST).
Power is supplied by a 4 ga. wire directly from the battery. I scraped off
paint under one of the seat mounting brackets and bolted the wire to that to
get a good ground.

The problem I'm having is calibrating the SWR meter. When key and hold down
the mic, I turn the meter's calibration knob all the way to the right and
the needle is still short of the calibration mark.

Any suggestions would be greatly appreciated.

Rob Kulp




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On Tue, 30 Mar 2004 15:20:20 -0500, Dave or Debby
wrote:

Don't buy Rat Shack junk!
Dave!


You mean don't buy any of Daves junk. You crow about your 25 years of
experience, but how many times have you answered someones question for
help? Why would anyone believe a word you say?

On Tue, 30 Mar 2004 12:23:39 -0500, Dave Hall
wrote:

On Tue, 30 Mar 2004 13:48:06 GMT, Lancer wrote:

On Tue, 30 Mar 2004 01:07:55 GMT, "Rob" wrote:

I installed a CB in my Jeep Rubicon for use when my buddies and I go trail
riding. I mounted a *ahem* 48" Radio Shack fiberglass whip on a right angle
antenna mount directly to the rear bumper. I ran a 20' Radio Shack 50 ohm
cable from the antenna to the transmitter mounted under the seat (Cobra 75
WX ST).
Power is supplied by a 4 ga. wire directly from the battery. I scraped off
paint under one of the seat mounting brackets and bolted the wire to that to
get a good ground.

The problem I'm having is calibrating the SWR meter. When key and hold down
the mic, I turn the meter's calibration knob all the way to the right and
the needle is still short of the calibration mark.

Any suggestions would be greatly appreciated.

Rob Kulp


First check what Frank and Dave suggested, then try this:

(hopefully your antenna is one of Radio Shacks adjustable ones)

1. Find out which channel gives you the lowest forward calibration
reading (1 or 40)

2. Note that reading

3. flip the switch to check the reverse reading.

4. Note that reading.

5. Change to the channel that gave you the highest forward calibration
reading.

6. Adjust the reading to same level as step 2.

7. flip the switch to check the reverse reading.

8. This will give you a "relative" SWR reading.

9. Depending on which channel gave you the lowest "relative" reading:
If your lowest reading was on channel 1, your antenna is too long.
If your lowest reading was on channel 40, your antenna is
too short.

Adjust your antenna.

And if this works as described, when you are done, take your radio to
a local tech to determine why your power out is so low....

Dave
"Sandbagger"

A really mismatched antenna could cause a low forward reading on an
SWR meter. Anyway, he did figure out that he had his meter backwards.

With the antenna shortened all the way, my SWR is 2.5 on channel 12 which is
the channel I will be using the most. I'm not sure if I should just leave it
alone, or if there is something else I can do to get a better reading. I
suppose I could replace the Radio Shack feedline I used.

I'm sure my power and grounds are good as I have no engine noise. I've heard
a lot of people with Jeep Wranglers have engine noise issues.

Any other comments or advice would be greatly appreciated.

Rob Kulp


"Rob" wrote in message
. com...
I hate to admit it, but the meter was hooked up backwards.
Thank you for the help.

On another note, on channel 1 my SWR is 2 and on channel 40 it's 3. The
antenna is a 48" Fiberglass whip from Radio Shack and is adjustable. I'm
guessing that I need to shorten the antenna?

Thanks again,

Rob Kulp

"Dave Hall" wrote in message
...
On Tue, 30 Mar 2004 01:07:55 GMT, "Rob" wrote:

I installed a CB in my Jeep Rubicon for use when my buddies and I go
trail
riding. I mounted a *ahem* 48" Radio Shack fiberglass whip on a right
angle
antenna mount directly to the rear bumper. I ran a 20' Radio Shack 50
ohm
cable from the antenna to the transmitter mounted under the seat (Cobra
75
WX ST).
Power is supplied by a 4 ga. wire directly from the battery. I scraped
off
paint under one of the seat mounting brackets and bolted the wire to
that
to
get a good ground.

The problem I'm having is calibrating the SWR meter. When key and hold
down
the mic, I turn the meter's calibration knob all the way to the right
and
the needle is still short of the calibration mark.

Any suggestions would be greatly appreciated.

If an SWR meter will not calibrate, there are 3 common reasons for
this (and a whole list of uncommon ones).
The first is an obvious lack of transmitter power. If your radio isn't
putting out at least a watt or 2, chances are you won't be able to
calibrate the meter.

The second is a radical fault in the antenna/feedline system. If the
cable or antenna mount is shorted, it can prevent the meter from
calibrating. One way to check this is to switch to the SWR position.
If the meter stays at the same point, you have a short.

The third common reason is a simple one. Is the meter hooked up
backwards? If you reverse the input and output connections, the meter
will not work properly, and you are actually trying to calibrate on
the reflected power (Which should be low). Again, a check for this
would be to switch to the SWR position. If the meter now pegs hard,
chances are you have it backwards.

Oh, and I just thought of a 4th reason. Are you sure you're on the
calibrate position?

Dave
"Sandbagger"
http://home.ptd.net/~n3cvj

Not 2.5, but 3.5.

Rob

"Rob" wrote in message
om...
With the antenna shortened all the way, my SWR is 2.5 on channel 12 which
is
the channel I will be using the most. I'm not sure if I should just leave
it
alone, or if there is something else I can do to get a better reading. I
suppose I could replace the Radio Shack feedline I used.

I'm sure my power and grounds are good as I have no engine noise. I've
heard
a lot of people with Jeep Wranglers have engine noise issues.

Any other comments or advice would be greatly appreciated.

Rob Kulp


"Rob" wrote in message
. com...
I hate to admit it, but the meter was hooked up backwards.
Thank you for the help.

On another note, on channel 1 my SWR is 2 and on channel 40 it's 3. The
antenna is a 48" Fiberglass whip from Radio Shack and is adjustable. I'm
guessing that I need to shorten the antenna?

Thanks again,

Rob Kulp

"Dave Hall" wrote in message
...
On Tue, 30 Mar 2004 01:07:55 GMT, "Rob" wrote:

I installed a CB in my Jeep Rubicon for use when my buddies and I go
trail
riding. I mounted a *ahem* 48" Radio Shack fiberglass whip on a right
angle
antenna mount directly to the rear bumper. I ran a 20' Radio Shack 50
ohm
cable from the antenna to the transmitter mounted under the seat
(Cobra
75
WX ST).
Power is supplied by a 4 ga. wire directly from the battery. I
scraped
off
paint under one of the seat mounting brackets and bolted the wire to
that
to
get a good ground.

The problem I'm having is calibrating the SWR meter. When key and
hold
down
the mic, I turn the meter's calibration knob all the way to the right
and
the needle is still short of the calibration mark.

Any suggestions would be greatly appreciated.

If an SWR meter will not calibrate, there are 3 common reasons for
this (and a whole list of uncommon ones).
The first is an obvious lack of transmitter power. If your radio isn't
putting out at least a watt or 2, chances are you won't be able to
calibrate the meter.

The second is a radical fault in the antenna/feedline system. If the
cable or antenna mount is shorted, it can prevent the meter from
calibrating. One way to check this is to switch to the SWR position.
If the meter stays at the same point, you have a short.

The third common reason is a simple one. Is the meter hooked up
backwards? If you reverse the input and output connections, the meter
will not work properly, and you are actually trying to calibrate on
the reflected power (Which should be low). Again, a check for this
would be to switch to the SWR position. If the meter now pegs hard,
chances are you have it backwards.

Oh, and I just thought of a 4th reason. Are you sure you're on the
calibrate position?

Dave
"Sandbagger"
http://home.ptd.net/~n3cvj

Try ignoring the cal function on the meter for a minute and just flip
through all your channels 1-40. At some point in the middle, you should hit
a low. If it's lowest point is on channel 1, your antenna is tuned to a
channel lower than 1. You need to shorten it. Many people will argue how low
it has to be but 1.5:1 or lower should be fine. There is one thing to keep
in mind. You said the antenna is bumper mounted. This can create problems
because alot of the vehicle (the antenna's ground plane) is beside the
antenna instead of under it. This is not to say that you can't get decent
performance with a 4 ft. bumper mounted but it depends on the vehicle and
the antenna. You may want to try a 6 ft. whip later.

Chris



I installed a CB in my Jeep Rubicon for use when my buddies and I go trail
riding. I mounted a *ahem* 48" Radio Shack fiberglass whip on a right
angle
antenna mount directly to the rear bumper. I ran a 20' Radio Shack 50 ohm
cable from the antenna to the transmitter mounted under the seat (Cobra 75
WX ST).
Power is supplied by a 4 ga. wire directly from the battery. I scraped off
paint under one of the seat mounting brackets and bolted the wire to that
to
get a good ground.

The problem I'm having is calibrating the SWR meter. When key and hold
down
the mic, I turn the meter's calibration knob all the way to the right and
the needle is still short of the calibration mark.

Any suggestions would be greatly appreciated.

Rob Kulp

"Rob" wrote:
With the antenna shortened all the way, my SWR is 2.5 on channel 12 which
is the channel I will be using the most.

What was your swr on channel 40?

Has anyone trimmed the whip on it? Is it a new cb antenna?

"Rob" wrote:
Thanks.

I'll see what I can do to improve those 2 things. I'll make it longer and
I'm going to go ahead and change to a better quality coax.

Robert Kulp

"Steveo" wrote in message
...
Your antenna is too short, or something is shorted in it,
or the coax.

Steveo wrote:
Your antenna is too short, or something is shorted in it,
or the coax.

Sun spots.

--
________________________
Pear pimples for hairy fishnuts?

"Steveo" wrote in message
...
Damn, I always get that backwards. :)

"Chris" wrote:
No, it's too long.

Duh!!!!!!


Landshark


--
Courage is what it takes to stand up
and speak; courage is also what it
takes to sit down and listen.

"Landshark" wrote in message
om...

"Steveo" wrote in message
...
Damn, I always get that backwards. :)

"Chris" wrote:
No, it's too long.

Duh!!!!!!


Landshark


--
Courage is what it takes to stand up
and speak; courage is also what it
takes to sit down and listen.


OOPppps, meant Doah!!!! Not Duh!

Landshark


--
The world is good-natured to people
who are good natured.

It's a new adjustable 48" fiberglass antenna from Radio Shack.

Rob

"Steveo" wrote in message
...
Has anyone trimmed the whip on it? Is it a new cb antenna?

"Rob" wrote:
Thanks.

I'll see what I can do to improve those 2 things. I'll make it longer
and
I'm going to go ahead and change to a better quality coax.

Robert Kulp

"Steveo" wrote in message
...
Your antenna is too short, or something is shorted in it,
or the coax.

On 31 Mar 2004 03:29:50 GMT, Steveo
wrote:

Your antenna is too short, or something is shorted in it,
or the coax.

"Rob" wrote:
That is after it is hooked up properly.

I have no problem calibrating now. The SWR readings are 2.5 on channel 1
and about 3.8 on channel 40.

Channel 12 was 3.5, not the 2.5 I had previously posted.



If the SWR is HIGHER on channel 40 than it is on channel 1, then the
antenna is TOO LONG.

Placement of the antenna is important too. I've seen guys with Jeep
setups who mount the whip to one of the "bumpers" within inches of the
vehicle body. This is not the smartest thing to do, and it will likely
affect the SWR.

Adjusting a fiberglass whip is a tricky operation. You can't
practically lengthen it, and if you cut it, and it doesn't help,
you've ruined an antenna.

Dave
"Sandbagger"
http://home.ptd.net/~n3cvj

On Tue, 30 Mar 2004 20:46:25 GMT, Lancer wrote:


Adjust your antenna.

And if this works as described, when you are done, take your radio to
a local tech to determine why your power out is so low....

Dave
"Sandbagger"

A really mismatched antenna could cause a low forward reading on an
SWR meter. Anyway, he did figure out that he had his meter backwards.

I sort of figured that was going to be his problem. A simple problem
that newbies sometimes make.

Dave
"Sandbagger"
http://home.ptd.net/~n3cvj

On Wed, 31 Mar 2004 06:51:27 -0500, Dave Hall
wrote:

On Tue, 30 Mar 2004 20:46:25 GMT, Lancer wrote:


Adjust your antenna.

And if this works as described, when you are done, take your radio to
a local tech to determine why your power out is so low....

Dave
"Sandbagger"

A really mismatched antenna could cause a low forward reading on an
SWR meter. Anyway, he did figure out that he had his meter backwards.

I sort of figured that was going to be his problem. A simple problem
that newbies sometimes make.

Dave
"Sandbagger"
http://home.ptd.net/~n3cvj

Yes, everyone has to do that at least once.

On Wed, 31 Mar 2004 11:34:15 GMT, "Rob" wrote:

Those readings are with the antenna as short as I can get it by turning a
screw head in the top of the antenna. =/

Rob


Its probably due to where you have it mounted. It will work the way
it is. At some point in the future, you might want to look at a
different antenna. One that you can get off the bumper and still
survive branches and trees.