Tell me about microphone cable?

[arudlang]

Hey all quick question. Let's say I am feeling clever and I want to take a stock 4 pin standard mic and crack it open and start adding buttons for additional features. Maybe channel changers up/down, for example.

Just assume I have modified the radio side connector to match, maybe I changed it to a 6 pin connector at the back of the radio..

What kind of wire do I have to seek out to replace the stock coiled microphone cable? I need something with more conductors inside for my buttons I added to the mic.

I see I can buy a replacement mic cord with 6 wires in it for about $12, is that the way I have to go for proper shielding and whatnot? Or... Could a person use something way cheaper like cat5e networking cable?

Sorry for the ignorance, as you can see I kinda can already guess the answer but I'm more looking to understand the what & why of it.

 

[mmckenna]

Ideally, you want the microphone circuit shielded. Failing to do that can sometimes result in unwanted RFI getting in and impacting audio.
PTT and simple switch closures for controls don't need to be shielded.



-Disclaimer-
Yes, someone is bound to come along and tell you that CAT5 works just fine for them, they talk more skip, get more swing, talk DX all day long and run full stereo hi-fi audio….. In short runs, you could probably get away with it, but longer runs, you don't. Kenwood had a ham radio that had a silly setup where it had a remote head, but the microphone plugged into the radio body. Some would use a simple CAT5 cable to run from the radio in the trunk up to the dashboard. Often they complained of audio issues.

Your choice, but shielded is what you'll find in the stock mic cable for a reason.

 

[arudlang]

Same kind of question for an extension. Suppose I have a decent spot for a radio on top of the dash of a car but I don't want the mic cable to hang down over all the infotainment and hvac controls. I'd like to create an extension cable to relocate the mic jack to the lower part of a dash panel.

Is there a source where I can buy that 6 wire cable with the shielded pair? I don't need it to be coiled, I just want to be able to make a short extension and possibly a device in the middle that adds something like scanning, roger beep, audio amplifier circuit, etc. Just ideas I have floating around.

Finding the right 6 pin connectors online was cheap and easy, I already have a bunch, but now trying to figure out where to get proper cable to use with them.

 

[mmckenna]

Any of the large online electronics dealers should have what you need, but buying cable that way can be expensive.
Probably easier to just buy a pre-made CB mic extension cable and modify it to do what you want.

 

[arudlang]

So throwing something like this over cat5e would not quite cut the mustard?

Amazon.com

 

[mmckenna]

The challenge is shielding the low level microphone audio signal from everything else. That can include any noise on the circuits for your PTT, channel change, etc. Usually the radio microphone cables have a circuit for the microphone that is shielded from everything else in the cable. Simply putting a shield over the entire cable won't necessarily solve the issue.

But, give it a try. If it's simple contact closure for PTT and your channel change, and the cable run is short, you might get away with it and no one will notice.

 

[Cognomen]

I recently replaced a mic cable on a CES 600L DTMF mic that had a disintegrating rubber casing (anyone remember those?). I used an 8-wire mic cable from an Kenwood KMC-35 commercial mic. Your local 2-way radio shop probably has a bin full of used mics, and you can probably find one with a decent-looking (non-stretched) coiled cord that you can get cheap or free. You don't even need the mic head.