Cobra 29 LTD Squelch

[NightRanger3151]

I have a Cobra 29 LTD. The squelch on these radios never completely quiets the radio unless you turn the squelch all the way to the right. Why Cobra did this I'll never know. I know of a lot of people that don't like the way the squelch operates on the 29 LTD's.

Is there a fix for this so it will perform like the squelches on most all other radios?

Thanks.

[Smitty]

RF gain........

[NightRanger3151]

RF gain........

no

[Rick]

If the Cobra 29 is the LTD Classic model, then set the Squelch control on the front of the radio to 12 a clock, then slowly adjust VR3 so the radio just go in to squelch.

[NightRanger3151]

If the Cobra 29 is the LTD Classic model, then set the Squelch control on the front of the radio to 12 a clock, then slowly adjust VR3 so the radio just go in to squelch.

The squelch is working just like it is suppose too from the factory. But when it just goes into squelch you can still hear a faint noise coming from the speaker. My other radios don't do that. They are completley quiet. Talking to other 29LTD owners they apparently all do it. I just want the thing to be quiet like the other radios when it squelches out the noise.

[Pioneer621]

NightRanger3151,
I have experienced that same thing with my Cobra 29 LTD’s, it probably has done it on the few dozen or more I have worked on, they must be designed like that. The noise is strange, it is kind of a muffled up static that is heard through the radios speaker when the SQUELCH is just above its threshold, you can make the noise go away by cranking up the squelch control, however, weaker stations may not break it at such a high point, which is a drawback.

Here is what I have found to reduce or completely eliminate the noise from just experimenting: Solder a 0.1uf (it has 104 on the cap) or a 0.01uf (103) (the 104 works better) ceramic capacitor across the middle pin (collector) of TR12 & the other leg (base) of TR12 towards the front of the radio, I have tried it on newer & older 29’s and it eliminated the noise, & the squelch circuit & the rest of the radio still seemed to function normal. So you just solder a 0.1uf (104) ceramic capacitor to TR12’s collector (middle pin) & TR12’s base (pin towards the front of the radio). TR12 is part of the squelch circuit.

I hope this info helps, again this was just from me experimenting so it may not be the best method, but it works fine for me & does not seem to hurt performance of the radio in any way & the squelch circuit seemed to work more like it is suppose to. Take Care & again hope this helps. Pioneer621

[NightRanger3151]

NightRanger3151,
I have experienced that same thing with my Cobra 29 LTD’s, it probably has done it on the few dozen or more I have worked on, they must be designed like that. The noise is strange, it is kind of a muffled up static that is heard through the radios speaker when the SQUELCH is just above its threshold, you can make the noise go away by cranking up the squelch control, however, weaker stations may not break it at such a high point, which is a drawback.

Here is what I have found to reduce or completely eliminate the noise from just experimenting: Solder a 0.1uf (it has 104 on the cap) or a 0.01uf (103) (the 104 works better) ceramic capacitor across the middle pin (collector) of TR12 & the other leg (base) of TR12 towards the front of the radio, I have tried it on newer & older 29’s and it eliminated the noise, & the squelch circuit & the rest of the radio still seemed to function normal. So you just solder a 0.1uf (104) ceramic capacitor to TR12’s collector (middle pin) & TR12’s base (pin towards the front of the radio). TR12 is part of the squelch circuit.

I hope this info helps, again this was just from me experimenting so it may not be the best method, but it works fine for me & does not seem to hurt performance of the radio in any way & the squelch circuit seemed to work more like it is suppose to. Take Care & again hope this helps. Pioneer621

Pioneer621,

Thanks for info. I agree it's the way the 29 LTD's are designed but I personally don't care for it. I will try what you suggested and let you know the results. Thanks again, your info sure worked out the last time I had a question here.

NightRanger3151

[NightRanger3151]

Pioneer621,

Thanks again! That worked to perfection! I have been annoyed by that ever-so-slight noise everytime it gets real quiet around that radio. I'll enjoy it more now.

You da man!

NightRanger3151

[Pioneer621]

NightRanger3151,

Thanks for the update! I am glad to hear it worked well for you, as it has for me. As I mentioned before, I am not sure if it is the greatest method, but it seems to work well & I cannot see any harm in doing the modification. I try to help out when I can. Take Care & have fun with your radios! Pioneer621