Question about Cobra 29 Lx Full-featured Cb Radio

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Have a new cobra 29lx. Everthing works fine except for the SWR meter. Can't use the meter to adjust SWR. No matter what I do the meter stays the same. Sent to factory but they said nothing was wro

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The SWR cannot be changed by rotating this knob. The SWR function allows you to determine the SWR or "match" of the antenna system and transmitter on a specific channel. The entire process must be performed whenever you want to know what the SWR is on a different channel. The SWR/CAL button toggles the meter between the CALIBRATE and SWR modes.
Set the radio to CH1. Press the SWR/CAL button. The radio CAL(ibrate) mode is now selected. Press and hold the mic PTT (or push to talk) button. Rotate the SWR knob as needed to adjust the meter indicator until it is on the SET mark on the dial. The meter is now calibrated for this channel.

While still holding down the mic PTT, press and release the S/RF SWR CAL button to the SWR setting to read the SWR on the meter.

This entire process should be done for Ch 20 and Ch 40. You must go through the CAL procedure for EACH channel before attempting to read the SWR.

Changing the SWR requires that the antenna be lengthened or shortened until such time that the SWR can be reduced no further. Typical SWR across the band may be:

CH1 - 1.5:1, CH20 - 1.1:1, CH40 1.5:1


CH1 - 2.2:1, CH20 - 1.7:1, CH40 2.3:1

The "dip" in SWR on CH20 is typical, as the antenna is the perfect length on only one channel - it will be come slightly too long or slightly too short as you tune up or down from CH20. The further away from CH20 you go, the poorer the SWR will be. You can "slide" the dip to any channel you prefer - say CH8. If you tune for lowest SWR on CH8, You might see CH1 with a 1.2:1 SWR, CH8 at 1.1:1 SWR and CH40 at 2.5:1. All are acceptable - sort of. Many manufacturers say up to 2.5:1 or even 3.0:1 matches are ok, There's no reason a quality antenna can't be tuned for optimum SWR in the middle of the band (CH20) to have less than a 2.0:1 SWR on CH1 or CH40, unless there is a ground issues or bad cable / antenna / connection somewhere.

You can view the manual here. I hope this helps & good luck!

Posted on Dec 03, 2012


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Posted on Jan 02, 2017

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SOURCE: I installed a browning br-51 cb antenna on my cb radio.

You need to shorten the antenna,adjust the whip all the way down and see what you have and then cut off 1/4" at a time remember this low on 1 high on 40 it needs to be lengthened high on 1 low on 40 it needs to be shortened . I hope this helps and good luck.

Posted on Apr 12, 2009

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SOURCE: Have Cobra 29 LTD Classic, no sound when hooked to

check the squelch by turning all the way both ways. check the external speaker socket. if it is the swicthing type it could be either bad conntact or dry joints. try an external speaker to see if that works. another thing is I believe it wont work if the microphone is not pluged in or connection fault there. Good luck.

Posted on Jul 25, 2010

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SOURCE: Have a cobra 148 gtl cb/ssb. It is brand new. I

Hi, my name is John. Welcome to FixYa. Check your antenna, you need to set it with a real SWR meter, pick one up at any near-by CB shack $10.00. Thanks for choosing Fixya...John

Posted on Nov 23, 2010

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Is there a way to get more range from a cobra 29 ltd? My buddy and I purchased this CB and are having difficulty getting a clear transmission at less than 1 mile apart on the freeway. Need help pleas

Is your buddy able to hear other radio traffic (squelch and RF gain adjusted for maximum reception)?
Is your microphone gain turned all the way up?

Did you follow the instructions for tuning the antenna with the built-in SWR meter? The built-in meter should be 'good enough' to get by with.

Is the antenna a decent brand/length? (Longer is better, the cellphone look-alikes are junk).
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I have tried 3 different antennas 2 magnetic and a k-40 solid mount now no matter what i do the swr is way to high and wont adjust and with 2 of them including the k-40 the antenna light comes on when i...

  • You need an external meter or at least replace the meter in your radio with another one. Even if it appears that meter is working right you need to put another one on there that will respond better. I repaired a Cobra 29 just two days ago with the same issue. The meter responded what looked to be great. Only the SWR was "8" so it said. I knew better. I had just tuned the radio and new better. I put in a new meter and the problem was resolved.
  • I always recommend an inline meter but the one on that CB should work good enough for a simple SWR check provided it is working right.
  • One more thing, not sure if the antennas you are using require you to provide a coax or weather the coax comes on the antenna already but I would suggest trying a new coax if your using the same coax for any of those antennas.
  • You may pop open the CB and make sure all legs of the P0239 antenna connector is solid.

  • Hope this helps and thank you for using FixYa.
  • If you have any questions feel free to ask.

Regards, Tony

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Check SWR with a meter, if its 1.1 to 1.5 then its fine no matter what the light says. The light can be adjusted inside to not light up until its very high(Its adjustable with a Variable knob inside) Get a Cb shop to check it out. I'd go for LIL Wilson 500 or 1000 antennas, I hear they are superb.

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what kind of meter? I would go by what is in the radio unless you are using an analyzer.

You may also be getting common mode current. take 6 to 8 inches of coax and make a tight coil about the same size as a spray paint can. Hold it together with electrical tape.

Use the meter in the LX LE to set the SWR then check with the other meter.

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