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Old 07-07-2016, 6:55 PM
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prcguy prcguy is offline
Join Date: Jun 2006
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I haven't had an old Motorola hand mic apart in ages but I don't think they had any Shure parts inside. Since the 1960s they used a dynamic element and transistor preamp fed with a bias voltage that emulated a carbon mic back to the radio.

The controlled magnetic reluctance mic element is simply another kind of dynamic mic and would by itself not be compatible with the input of a Motorola radio. At the minimum you would have to cap couple the element if DC bias was on the mic audio leads and a dynamic element without a preamp would come up short on drive level for a Motorola. Any modern preamp CB/ham mic will work fine.

On the mic pictured by the OP, oh my, that belongs in a museum and not on a modern radio. I just checked my Mocat radio and when you remove the mic receive audio goes away. That means any mic for that series needs a set of contacts that closes during receive and opens during transmit, in addition to the contacts that close during transmit for PTT. If your ancient mic has the needed contacts it will certainly work on your Motorola CB, but I would be embarrassed to tell anyone I was using it.

The most awesome thing you can do for your Motorola radio is get the "L" mic I listed in a previous post, they are cheap and sound fantastic on these radios. I can also give you pinouts from the mic body to the connector because I have one working now on an Mocat.

Originally Posted by Dawn View Post
The desk mic shown in the picture is from the consolette series and desk remotes and designed for carrier squelch only. Inside the housing is a Shure Bros. controlled reluctance microphone unless this one is different for some reason or someone replaced the original element. These mic elements were developed as a direct replacement of a carbon button microphone with similar high output and nominal impedance. They also use the bias voltage that the carbon mics used to power the controlled reluctance element unlike a dynamic mic found on most CB's. If I take the above to be correct, then there is already a source of voltage that may be enough to power the mic element.

While I understand that the OP wants to use this mic with the station, Pcrguy is correct in recommending one of the "L" mics if that is what the link refers to.

The Mocat housing and design is much the same of the Maxar/Moxy/Flexar stations and similar remotes and some Nautilus marine coastal stations. These all used the white/dark gray L mics for fixed station use.

Another caveat regarding the above mic. If you do decide to use it, do not use the mic cord attached to it and remove the connector. It will be a disaster as there is 50+ year old tinsel cord inside. Even when new, you could not solder it to a mic connector without using special crimps that dug into the cord in between the interwoven fabric and copper wire. Even if you had the special crimps, probability is that the copper in the tinsel is already very oxidized and probably couldn't make a good "bite" inside the wire.

Last edited by prcguy; 07-07-2016 at 7:06 PM..
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