Why does my volume/squelch suddenly drop out?

It could be one of several things, RPP. If you are in a truck stop or otherwise in close proximity to others who might be transmitting on CB or nearby frequencies with strong signals, your receiver may be experiencing de-dense, whereby your receivers sensitivity will drop tremendously while they are transmitting. Scan up snd down the band when this happens and if you find a really strong signal on another channel, de-sense may be your culprit. Notice if it comes and goes and the duration of its presence. Is it like the pattern of a normal keydown(s) for someone conversing? That might be another clue that it is de-sense.

Another possibility might be dirty volume and/or squelch pots on your radio. Cobras are notoriously bad for this problem as they must use the cheapest pots on the planet for volume, squelch, and other controls such as "SWR Calibrate". If the problem comes and goes in time with you running your volume and/or squelch up and down, this is likely your problem. Aerosol contact cleaning sprays may give you some relief for a while. I would gladly pay another $20-50 for a radio that used quality pots for volume and squelch controls, just to avoid this problem. Cobra, are you listening?

One other thing to check is your microphone connector and cable. If your radio uses the old style of electronic switching, you will hear nothing through the speaker if the mic is not connected. If such is the case with your radio, you might have a short or open connection in your mic, mic cord, or connector.

Finally, don't forget to check your antenna system for bad connections. Is the PL-259 tight on the back of your radio? I've lost count of the times this simple problem has caused friends or myself grief.

Good luck in diagnosing and fixing your problem.

 

Interesting! The de-sense would almost definitely occur to either radio, while transmitting on the other, in such an arrangement, if on different channels. If only receiving at the time on both radios, it is not likely to be a problem. Of course, if transmitting on one while receiving on the other, while both are on the same channel, you might get anything from bad feedback (squealing) to damaged components on the receiving radio.

 

How does a squelch drop out?

If you are using a radio with a squelch, it's purpose is to silence the audio below a specific signal level.

 

turn down your rf gain. Some signals may still overload the radio. If as someone mentioned you are listening to one while transmitting on the other just turn one off.

 

Neverready covered the answer very well! Dropping your rf gain may help if you are getting the de-sense from nearby truckers or others while on the road or in a truck stop. I don't think it is within the realm of feasibility to not get de-sense while transmitting on one CB radio and receiving on another CB when both are in the same vehicle.

Usually, if I'm getting de-sense and the source is on one of the standard 40 channels that my radio has, I'll flip around the band until I find what channel they're on and monitor them at least until we are far enough apart that they no longer de-sense my radio. Of course if you are sitting in a truck stop and they are also, this could be quite a while.