Question about Cobra 29 LTD CB Radio

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My swr are high with proper calibration - Cobra 29 LTD CB Radio

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  • stevencazun
    stevencazun Feb 20, 2012

    I just got a new cascadia. I pluged in my radio and lined up the red calibration line. when I move the switch up to SWR it shoots to 3 and over.

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You may need to retune the antenna system if the coax has not been kinked or damaged. If you simply moved it over from the old rig, the antenna was tuned to that layout and the groundplane was the shell of the truck and chassis. The Cobra can tune it somewhat, but the best results are achieved with a baseline adjustment of the antenna. But check the coax for damage first, then check the connections to the antennas. If you are using a baseloaded whip, there is actually an inductor wound that attaches to chassis/coax ground, and it may be corroded. As may the center conductor terminal at the antenna.

If those sheck out okay Check to see if your SWR is higher on 40 than on 1, or if it is higher on 1 than on 40.

if it is higher on 40 than on one, shorten the antenna slightly, first and see how it looks.

If it is higher on 1 than on 40 try lengthen it slightly and see how it looks.

If you are running with dual whips, that complicates matters a little bit due to phasing.

I had set up a radio to be portable from vehicle to vehicle and found changing tuning length was always required when I moved it to a new vehicle. What made matters worse was I chose a cheap Walmart baseload and it had lousy quality coax.

Posted on Feb 20, 2012

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1 Answer

When my calibration needle is all the way in the area my swr is really high


When your needle is all the way in the RED, your swr IS really high. That's what the meter is telling you. You need to clean all of the antenna connection points and adjust the length of the antenna to reduce the SWR (standing wave ratio) which is basically resistance to transmitting signals.

Oct 15, 2013 | Cobra 29 LTD CHR CB Radio Chrome Special...

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 | Radio Communications

1 Answer

Cobra 29XL: SWRs to high after calibrating according to the manual


tune your antenna not you radio. sounds like you don't have it grounded properly. new radio,new coax,and new antenna is the only way to do it right.make sure your antenna is at least 40" and it is adjustable with a set screw.

Dec 06, 2012 | Cobra Radio Communications

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

I have full power but no white noise as they call it.it wont calibrate either.when useing swr or calibrate switch.


Turn your RF gain all the way up. There is no need to turn it down. Make sure the squelch is down. Also, some days it's just really quiet out. You can turn the radio on some day and hear nothing. Or you could have a problem with the mic.

As for the calibrating. You do not calibrate the radio. that is for calibrating the meter to read the SWR of the antenna. Here is how to tune our 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.

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

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 Radio Communications

1 Answer

My antenna light stays on even after I have realeased the mike


Try checking the SWR's on channel 1, 20, and 40. The SWR's will change from the low channels to the mid channels to the high channels. The key is to make sure that the SWR's are around 1 or less at all three points. If the light goes out when checking one of them, then the problem is most likely the SWR's. If the light stays on when checking these channels, the issue might still be the SWR's but I would look at the grounding on the antennas. When holding the talk button on the mic and switching from calibrate to swr, can give a false reading. This is due to the calibrate circuit remaining open until you release the talk button. Take the SWR reading by releasing the Talk button on the mic after calibrating then pressing the talk button again after switching back to SWR. This will be the most accurate reading. From everything you described, I would be looking for a grounding problem with the antennas or coax, possibly even a rub though on the coax somewhere in the dash.

Dec 20, 2009 | Cobra 29 WX NW ST 40-Channels Base CB...

1 Answer

Cobra 29 NW LTD Classic wont calibrate and red antenna light keeps coming on


The calibrate knob only calibrates the radios SWR meter, the owners manual will show you the procedure for that. If your ANT light is coming on, it is telling you that your SWR is to high, and may cause damage to the radio from reflected power. You should purchase an in line meter as the radios internal meter may be somewhat unreliable. You need to tune the antenna to the lowest SWR possible. Typically anything under 2.0:1 is acceptable. Radio Shack sells a meter for about $50, and is pretty accurate. Antenna mounting can also cause high reflection if it is to close to other objects. Google "CB antenna tuning" or read the instruction manual for you antenna, and you should be able to figure out how to properly tune the antenna.

Jul 07, 2009 | Cobra 25 NW LTD 40-Channels Base CB Radio

1 Answer

John Q president cb


Hi,

If by calibration, you are referring to the check if your antenna is tuned, below information may be of help.
S/RF/SWR/CAL SWITCH. When in the S/RF position, the meter swings
proportionally to the strength of the received signal. When transmitting,
the meter indicates relative RF output power.
When in the "CAL" position, the SWR meter can be calibrated by adjusting
the "SWR CAL" control to the "CAL" mark on the meter face.
When in the "SWR" position, the standing wave ratio is measured.

SWR METER. Measures standing wave ratio of the antenna system.
Used to properly adjust the length of the antenna and to monitor the
quality of the coaxial cable and all RF electrical connections. If there is any
degradation whatsoever in any of the foregoing, due to humidity, salt
spray, vibration or corrosion, the SWR meter reading will rise, thereby
indicating that a problem exists.
To calibrate, switch to the "CAL" position, transmit by pressing the mike
switch, and adjust the SWR control to the "CAL" mark on the meter; then
switch to "SWR" position for the SWR measurement.

If however you are referring to the internal calibration or tuning of the transmit and receive sections, you would need several instruments/equipment such as RF generator (0-30Mhz with 1Khx modulation), Spectrum Analyzer, Modulation Scope, Dummy Loaded Wattmeter, Frequency Meter and some others. These of course are not readily available to the average user.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards.

Thank you for using FixYa.

Jun 12, 2008 | Cobra 29 LTD CB Radio

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