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Old 07-06-2016, 9:27 AM
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Nonsense. The Motorola Mocat series uses the same type of mic as the commercial FM radios which is an electret condenser capsule and a little preamp board. There is 8V or so on the mic cable from the radio to power the preamp.

The stock mic puts out a bit more voltage than a typical dynamic mic, so you would not be able to replace with one of those but a common preamp CB mic works great on these radios. I've wired a number of mics to these radios but forgot which ones since its been 35+ years ago but it would have been a preamp D104 or Turner +3 or SuperSidekick, etc.

I think the Mocat series uses electronic switching between transmit and receive and you can test this by unplugging the mic and see if the receive audio goes away. If so the mic must have a secondary switch that closes to complete a path on the receive side and the mic you pictured may not work in this case.

Probably the best mic you can put on the radio is an actual Motorola base mic from a Spectra or similar radio. These are a direct match to the radio and have an internal gain control you can crank up and they sound great on these radios. Here is one example and you can sometimes find them for $5 used.
New in Box Motorola Desk Microphone TMN1005B | eBay

Originally Posted by KC2GIU View Post
Your radio is basically the famous MOCAT 40 CB. Once the mic dies, it's nearly impossible to replace since Motorola doesn't have any replacement parts and there isn't any 3rd party knock-offs in existence today.

BUT ...

The problem is, the pre-amp is in the radio on the MOCAT 40 T4000 series radios, not in the mic. Thus a power-mic will not work.
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