Question about Cobra 29 LTD CB Radio

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High swr ch. 1- 5 and ch. 40 - 5 - Cobra 29 LTD CB Radio

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What?

"Sometimes the CB will put out more power on a channel than is needed?" Perhaps true, but in 99.9% of situations, the problem is being caused by an impedance mismatch. And this impedance mismatch is being caused by the antenna being out-of-tune (for the frequency of transmission), OR perhaps the antenna has a very low "Q", or bandwidth. This ("low bandwidth antenna" may be the case mentioned by paularenee1, as the SWR seems to be increasing at both the lowest and highest frequencies of the CB).

Given that... Tune the antenna for lowest SWR on your "home channel" (or the channel upon which you most converse) and forget about it...

Happy modulating!

Remember: (for copper, anyways) length in feet of 1/2 wave antenna = 468/freq in MHz.

Posted on Mar 20, 2009

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  • Contributor
  • 66 Answers

This is a common problem in CB's. You can either get the radio tuned properly or tune the antenna. Sometimes the CB will put out more power on a channel than is needed and this could end up in a damaged radio. You can get the radio tuned to prevent the RADIO from high SWR, or you can tune the ANTENNA so tha antenna will better suit your CB's power.

Hope this helps!

Posted on Jul 01, 2008

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ButtFuzz
  • 463 Answers

SOURCE: iv got a problm with mt swr i have a magnett mount

What sort of antenna are you using? Wilson, K-40, etc? Also, is the antenna right near any metal or perhaps you have heated rear glass (which means you have thin strips of copper in close proximity to your antenna).

Any of these things can cause enough impedence mismatch to cause your VSWR to rocket skyward.

Posted on Mar 06, 2009

  • 7 Answers

SOURCE: high SWR

the problem is in the antenna cable. the lenth of a antenna cable must be divisable by 3. try replaceing cable with a 18 foot cable that should fix the problem.

Posted on Apr 22, 2009

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1 Answer

How do I fix SWR spikes?


For CB radio that operates in a relatively narrow bandwidth, you should be able to obtain "perfect" SWR readings for all 40 channels. That would be a reading of 1.1 : 1 or less.
The rule of thumb goes like this: if SWR is HIGHER on HIGHER FREQUENCY (Ch. 40 is higher than Ch. 1) then the antenna whip is too HIGH (too long/tall) therefore it must be shortenned. And vice versa.
Trimming the length requires patience especially when the reading has reached 1.5 : 1 or lower/better. Make a 5mm trim each time and then measure SWR then continue trimming until you are satisfied with the results.
The spike must be contributed by faulty electronic components inside the radio. The radio must be checked by a technician. But before you do that, trim your whip first and see what happens. Ideally, the length of the coax cable must be trimmed as well. But, since we don't live in an ideal world, we can ignore that for the time being. Goodluck. es

Jun 10, 2013 | CB Radios

Tip

How to tune your SWR on your CB Radio.


It is important to tune your CB radio antenna to the proper length. The length must exactly match the wavelength of the frequency you transmit on. Or be really really close.

All Cb antenna's have a way to adjust the length of the antenna. If it's a mag mount, the metal whip can be slid in and out of a metal collar. Usually a set screw. If its a fiberglass whip, the way to tune it is on top. It either has a small metal rod with a set screw to adjust the length, or it threads in and out to adjust length.

Either type you have it will need to be adjusted for proper length. Here is how to tune the antenna to lowest SWR.

Some radios have a built in SWR meter. Some do not. If yours doesn't have an SWR meter, then you have to use an external SWR meter. Radio shack carries one, and you can find them cheap on ebay.

If you have a built in SWR meter or external, the procedure is the same:

1. Turn the radio to CH 20.(This is the center of the band.)
2. Switch the meter switch to CAL. (CAL stand for calibrate.
3. Key the radio. (Important. Do not talk while keying the radio.)
4. turn the CAL knob up until the meter hits the CAL mark.
5. Now while still keying the radio flip the meter switch to SWR.

Where the meter falls after that point is you SWR reading. If its above 3, that is real bad. 2 is not gonna kill your radio but its not the greatest. 1.5 and under is a good place to be, but the lower the better.

If your SWR is high, Here is how to find out if your antenna is too long or too short.

1. Turn to CH 1
2. Repeat SWR procedure. You must calibrate every time you do it.
3. Remember the SWR reading.
4. Turn to CH 40.
5. Again repeat SWR procedure.
6. Compare the reading between CH 1 and CH 40.

Now if the SWR is higher on channel 1 then channel 40 your antenna is too short. You must make it longer.

If the SWR is longer on channel 40 then on channel 1, then the antenna is too long, you need to make it shorter.

Make height adjustments about an eight inch at a time, and take reading each time.

once the SWR is significantly lower and the reading on channel 1 and 40 are about the same, you a about matched. At this point turn the radio to the center of the band, channel 20 and take an SWR reading.

You should now have a low SWR reading, 1.5 or under. If you are 1.5 or under, you are good to go.

If you cannot get the SWR to an appropriate level, there may be an antenna problem.

on Sep 08, 2010 | CB Radios

1 Answer

It says cb atanna warning when i key the mic. i have a new cable and new atannas as of 20 min ago. what is the problem


The problem is you need to tune the antenna.



It is important to tune your CB radio antenna to the proper length. The length must exactly match the wavelength of the frequency you transmit on. Or be really really close.

All Cb antenna's have a way to adjust the length of the antenna. If it's a mag mount, the metal whip can be slid in and out of a metal collar. Usually a set screw. If its a fiberglass whip, the way to tune it is on top. It either has a small metal rod with a set screw to adjust the length, or it threads in and out to adjust length.

Either type you have it will need to be adjusted for proper length. Here is how to tune the antenna to lowest SWR.

Some radios have a built in SWR meter. Some do not. If yours doesn't have an SWR meter, then you have to use an external SWR meter. Radio shack carries one, and you can find them cheap on ebay.

If you have a built in SWR meter or external, the procedure is the same:

1. Turn the radio to CH 20.(This is the center of the band.)
2. Switch the meter switch to CAL. (CAL stand for calibrate.
3. Key the radio. (Important. Do not talk while keying the radio.)
4. turn the CAL knob up until the meter hits the CAL mark.
5. Now while still keying the radio flip the meter switch to SWR.

Where the meter falls after that point is you SWR reading. If its above 3, that is real bad. 2 is not gonna kill your radio but its not the greatest. 1.5 and under is a good place to be, but the lower the better.

If your SWR is high, Here is how to find out if your antenna is too long or too short.

1. Turn to CH 1
2. Repeat SWR procedure. You must calibrate every time you do it.
3. Remember the SWR reading.
4. Turn to CH 40.
5. Again repeat SWR procedure.
6. Compare the reading between CH 1 and CH 40.

Now if the SWR is higher on channel 1 then channel 40 your antenna is too short. You must make it longer.

If the SWR is longer on channel 40 then on channel 1, then the antenna is too long, you need to make it shorter.

Make height adjustments about an eight inch at a time, and take reading each time.

once the SWR is significantly lower and the reading on channel 1 and 40 are about the same, you a about matched. At this point turn the radio to the center of the band, channel 20 and take an SWR reading.

You should now have a low SWR reading, 1.5 or under. If you are 1.5 or under, you are good to go.

If you cannot get the SWR to an appropriate level, there may be an antenna problem.

Aug 10, 2011 | Cobra CB Radios

1 Answer

The light for high swr keeps coming on. replaced antenna and coaxle. how do i go about lowering the swr. is there a nob or switch for this. thank you


You cannot lower the SWR via the radio. it has to do with the antenna. The length of the antenna is essential to transmitting properly. It must match the transmitting frequency.

To check SWR tune to ch 20. Flip the meter switch to CAL. Key the radio without talking into the radio. Turn the CAL knob up until the meter needle is at the CAL mark. Unkey the mic. Flip the meter switch to SWR. key the radio again, and the meter will show your SWR. We already know it is high because you are getting antenna warning, but we will have a base line now to work on.

What you did was calibrate the meter for that channel. that is necessary to check the SWR. So you must calibrate for each channel you check.

You should at least be under 2 swr. Ideal is 1.5 or under. the lower the better.

If your SWR is high, your antenna is either too long or too short. To find out here is what you do:

Check the SWR on ch 1 and ch 40 calibrating for each channel. Compare the difference of the SWR between 1 and 40. If the SWR is higher on 40 then 1, your antenna is too long. If your SWR is higher on 1 then 40 your antenna is too short. All CB antennas have a way to adjust the length.

If its a mag mount, its usually a set screw you loosen to raise or lower the whip. Fiberglass antenna's usually have something under the cap at the tip to adjust. It will either be like the mag mount, with a set screw and a small rod to raise or lower it, or a screw, that you screw in or out to make it longer or shorter.

make small adjustments. 1/8th or a 1/4 of an inch at a time. Each time you make a change, take an SWR reading on 1 and 40 again and compare the difference. The difference should be getting less. Do this until there is very little or no difference between 1 and 40.

Then you go back to 20, because it is the center channel and check the SWR there. It should now be low. If you did a good job it will be under 1.5 and you are good to go.

Aug 07, 2011 | Galaxy Radios DX-93T Base CB Radio

1 Answer

How do i set up, calibrate my cb


Your wanting to calibrate your ANTENNA. put on ch1 change switch to SET, key mic adjust cal knob to edge of red in meter should have a lil arrow. then change switch to SWR it should show the SWR of the ANtenna system. You'll want SWR to be 1.5 or less under the 2 in the green. Do the same on ch 40 and compare readings. remeber ch 1 is a longer wavelength than ch 40..

so if its good on ch1 and high on ch 40 make it shorter
and vice versa, bad on 1 and good on 40 make longer
Then try to get them balanced ..... or have the cb shop in templetx do it they will normally do it for free except for parts to fix any problems.

Dec 13, 2010 | Cobra 29 LTD CB Radio

2 Answers

I have a swr meter and i would like to no how to ues it


Goto channels 1 20 and 40 and do the following.... this a generic calibrate all swr meters have different buttons different style of meters etc...
set meter too the set/cal/fwd position. key mic adjust the meters needle to cal spot should have an arrow or red line etc. then change switch to swr/rev too show your reflected swr.

ch 1 is longer wavelength than ch 40.
if ch 1 is good swr and ch40 is high swr-- then make antenna shorter
if ch 40 is good swr and ch 1 is high swr-- then make antenna longer.
then try to get a good balance between the lowest freq and the highest freq./ch.
-- anymhz(dot)com ---- Radio Shop

Dec 06, 2010 | CB Radios

1 Answer

I just got a cobra 29ltd army edition and i cant get the SWR right


Takes some time to get it down if you are new to it. Here is a step by step instruction on setting it.....



It is important to tune your CB radio antenna to the proper length. The length must exactly match the wavelength of the frequency you transmit on. Or be really really close.

All Cb antenna's have a way to adjust the length of the antenna. If it's a mag mount, the metal whip can be slid in and out of a metal collar. Usually a set screw. If its a fiberglass whip, the way to tune it is on top. It either has a small metal rod with a set screw to adjust the length, or it threads in and out to adjust length.

Either type you have it will need to be adjusted for proper length. Here is how to tune the antenna to lowest SWR.

Some radios have a built in SWR meter. Some do not. If yours doesn't have an SWR meter, then you have to use an external SWR meter. Radio shack carries one, and you can find them cheap on ebay.

If you have a built in SWR meter or external, the procedure is the same:

1. Turn the radio to CH 20.(This is the center of the band.)
2. Switch the meter switch to CAL. (CAL stand for calibrate.
3. Key the radio. (Important. Do not talk while keying the radio.)
4. turn the CAL knob up until the meter hits the CAL mark.
5. Now while still keying the radio flip the meter switch to SWR.

Where the meter falls after that point is you SWR reading. If its above 3, that is real bad. 2 is not gonna kill your radio but its not the greatest. 1.5 and under is a good place to be, but the lower the better.

If your SWR is high, Here is how to find out if your antenna is too long or too short.

1. Turn to CH 1
2. Repeat SWR procedure. You must calibrate every time you do it.
3. Remember the SWR reading.
4. Turn to CH 40.
5. Again repeat SWR procedure.
6. Compare the reading between CH 1 and CH 40.

Now if the SWR is higher on channel 1 then channel 40 your antenna is too short. You must make it longer.

If the SWR is longer on channel 40 then on channel 1, then the antenna is too long, you need to make it shorter.

Make height adjustments about an eight inch at a time, and take reading each time.

once the SWR is significantly lower and the reading on channel 1 and 40 are about the same, you a about matched. At this point turn the radio to the center of the band, channel 20 and take an SWR reading.

You should now have a low SWR reading, 1.5 or under. If you are 1.5 or under, you are good to go.

If you cannot get the SWR to an appropriate level, there may be an antenna problem.

Nov 12, 2010 | Cobra 29 LTD CB Radio

1 Answer

I lost my manual and I don't know how to calibrate my CB its a cobra 29Ltd chrome edition


It is important to tune your CB radio antenna to the proper length. The length must exactly match the wavelength of the frequency you transmit on. Or be really really close.

All Cb antenna's have a way to adjust the length of the antenna. If it's a mag mount, the metal whip can be slid in and out of a metal collar. Usually a set screw. If its a fiberglass whip, the way to tune it is on top. It either has a small metal rod with a set screw to adjust the length, or it threads in and out to adjust length.

Either type you have it will need to be adjusted for proper length. Here is how to tune the antenna to lowest SWR.

Some radios have a built in SWR meter. Some do not. If yours doesn't have an SWR meter, then you have to use an external SWR meter. Radio shack carries one, and you can find them cheap on ebay.

If you have a built in SWR meter or external, the procedure is the same:

1. Turn the radio to CH 20.(This is the center of the band.)
2. Switch the meter switch to CAL. (CAL stand for calibrate.
3. Key the radio. (Important. Do not talk while keying the radio.)
4. turn the CAL knob up until the meter hits the CAL mark.
5. Now while still keying the radio flip the meter switch to SWR.

Where the meter falls after that point is you SWR reading. If its above 3, that is real bad. 2 is not gonna kill your radio but its not the greatest. 1.5 and under is a good place to be, but the lower the better.

If your SWR is high, Here is how to find out if your antenna is too long or too short.

1. Turn to CH 1
2. Repeat SWR procedure. You must calibrate every time you do it.
3. Remember the SWR reading.
4. Turn to CH 40.
5. Again repeat SWR procedure.
6. Compare the reading between CH 1 and CH 40.

Now if the SWR is higher on channel 1 then channel 40 your antenna is too short. You must make it longer.

If the SWR is longer on channel 40 then on channel 1, then the antenna is too long, you need to make it shorter.

Make height adjustments about an eight inch at a time, and take reading each time.

once the SWR is significantly lower and the reading on channel 1 and 40 are about the same, you a about matched. At this point turn the radio to the center of the band, channel 20 and take an SWR reading.

You should now have a low SWR reading, 1.5 or under. If you are 1.5 or under, you are good to go.

If you cannot get the SWR to an appropriate level, there may be an antenna problem.

Oct 21, 2010 | Cobra 29 LTD CB Radio

1 Answer

I am showing a antenna issue with both my galaxcy and the new cobra cb i bought i replaced the wire with a 18in but still didnt solve the problem


Did you try adjusting the antenna for lowest SWR? If so, the problem could be your antenna. It might be a poor antenna.



It is important to tune your CB radio antenna to the proper length. The length must exactly match the wavelength of the frequency you transmit on. Or be really really close.

All Cb antenna's have a way to adjust the length of the antenna. If it's a mag mount, the metal whip can be slid in and out of a metal collar. Usually a set screw. If its a fiberglass whip, the way to tune it is on top. It either has a small metal rod with a set screw to adjust the length, or it threads in and out to adjust length.

Either type you have it will need to be adjusted for proper length. Here is how to tune the antenna to lowest SWR.

Some radios have a built in SWR meter. Some do not. If yours doesn't have an SWR meter, then you have to use an external SWR meter. Radio shack carries one, and you can find them cheap on ebay.

If you have a built in SWR meter or external, the procedure is the same:

1. Turn the radio to CH 20.(This is the center of the band.)
2. Switch the meter switch to CAL. (CAL stand for calibrate.
3. Key the radio. (Important. Do not talk while keying the radio.)
4. turn the CAL knob up until the meter hits the CAL mark.
5. Now while still keying the radio flip the meter switch to SWR.

Where the meter falls after that point is you SWR reading. If its above 3, that is real bad. 2 is not gonna kill your radio but its not the greatest. 1.5 and under is a good place to be, but the lower the better.

If your SWR is high, Here is how to find out if your antenna is too long or too short.

1. Turn to CH 1
2. Repeat SWR procedure. You must calibrate every time you do it.
3. Remember the SWR reading.
4. Turn to CH 40.
5. Again repeat SWR procedure.
6. Compare the reading between CH 1 and CH 40.

Now if the SWR is higher on channel 1 then channel 40 your antenna is too short. You must make it longer.

If the SWR is longer on channel 40 then on channel 1, then the antenna is too long, you need to make it shorter.

Make height adjustments about an eight inch at a time, and take reading each time.

once the SWR is significantly lower and the reading on channel 1 and 40 are about the same, you a about matched. At this point turn the radio to the center of the band, channel 20 and take an SWR reading.

You should now have a low SWR reading, 1.5 or under. If you are 1.5 or under, you are good to go.

If you cannot get the SWR to an appropriate level, there may be an antenna problem.

Oct 18, 2010 | Cobra CB Radios

1 Answer

WHEN I TAKL HAVE DISTORTION MY COBRA IS CB COBRA 19 ULTRA 111 BUY NEW. SOME PEOPLE SAY YOUI ARE OUT OF FQ.


your not out of frequency. Your antenna is not tuned.

It is important to tune your CB radio antenna to the proper length. The length must exactly match the wavelength of the frequency you transmit on. Or be really really close.

All Cb antenna's have a way to adjust the length of the antenna. If it's a mag mount, the metal whip can be slid in and out of a metal collar. Usually a set screw. If its a fiberglass whip, the way to tune it is on top. It either has a small metal rod with a set screw to adjust the length, or it threads in and out to adjust length.

Either type you have it will need to be adjusted for proper length. Here is how to tune the antenna to lowest SWR.

Some radios have a built in SWR meter. Some do not. If yours doesn't have an SWR meter, then you have to use an external SWR meter. Radio shack carries one, and you can find them cheap on ebay.

If you have a built in SWR meter or external, the procedure is the same:
  1. Turn the radio to CH 20.(This is the center of the band.)
  2. Switch the meter switch to CAL. (CAL stand for calibrate.
  3. Key the radio. (Important. Do not talk while keying the radio.)
  4. turn the CAL knob up until the meter hits the CAL mark.
  5. Now while still keying the radio flip the meter switch to SWR.
Where the meter falls after that point is you SWR reading. If its above 3, that is real bad. 2 is not gonna kill your radio but its not the greatest. 1.5 and under is a good place to be, but the lower the better.

If your SWR is high, Here is how to find out if your antenna is too long or too short.

  1. Turn to CH 1
  2. Repeat SWR procedure. You must calibrate every time you do it.
  3. Remember the SWR reading.
  4. Turn to CH 40.
  5. Again repeat SWR procedure.
  6. Compare the reading between CH 1 and CH 40.
Now if the SWR is higher on channel 1 then channel 40 your antenna is too short. You must make it longer.

If the SWR is longer on channel 40 then on channel 1, then the antenna is too long, you need to make it shorter.

Make height adjustments about an eight inch at a time, and take reading each time.

once the SWR is significantly lower and the reading on channel 1 and 40 are about the same, you a about matched. At this point turn the radio to the center of the band, channel 20 and take an SWR reading.

You should now have a low SWR reading, 1.5 or under. If you are 1.5 or under, you are good to go.

If you cannot get the SWR to an appropriate level, there may be an antenna problem.

Jun 21, 2010 | Cobra CB Radios

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