CDM1250 Static from Mic

[ssfc1832]

Hello, I recently installed a Motorola CDM 1250 Low Band 42-50 in my truck. It came with a cat-5 dummy plug w/ground jumper to plug into the front mic. jack in place of a mic. When plugged in, it scans normally and stops only when someone keys up on any of the channels. When I remove the dummy plug and install a standard Motorola microphone, it hangs on the CSQ channels. Unfortunately the main dispatch channel in our county doesn't use a PL tone, so that channel must be set for carrier squelch. This occurs when the mic is on the hook, it does exit monitor mode, but still hangs on CSQ. This was not an issue on my old Maxtrac mobile.

Wondering what the problem is. Do I need to ground the mic. clip? I'm trying to avoid drilling holes for that purpose as there is no good place to put the mic. clip. I've been using heavy duty double-sided sticky tape and it's been working well on the mic. clip, but without the screw, the clip itself is not grounded. I have tried bending the clip for a more snug fit (and consequently better ground) for the two contacts on the back of the mic but it still seems to hang on the CSQ channels. If I have the mic. off the hook and in my hand, I seem to be enough to ground it out, the static disappears, and scan resumes. Placing the microphone off the hook and on the seat next to me causes the radio to hang on the CSQ channels.

Would a remote head help or hurt? I was planning on converting it to a remote head radio in a few weeks anyway.

Any thoughts would be appreciated on this manner. Thanks.

[Bill_G]

What model of mic are you using? Is it factory, or has it been modified? Have you tried grounding the back of the mic to the car or the CDM chassis with a piece of wire?

Scan enable should not be affected by PL or CSQ. It should only pay attention to the mic being on or off hook, and I think the CDM can be prog'd to ignore the hook switch.

[ssfc1832]

I switched from a black Motorola mic. made in Malaysia to a spare white Motorola HMN1056D and the problem went away. Don't think the microphones were modified in any way, although I'm not the original owner of either one.

Thanks for your reply.

[Bill_G]

You're welcome.

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