(This applies to my radio, green circuit board US export version but possibly identical to all the other clones....
From the internal microphone plug:
RED wire- Direct to ground for PTT, in series with 2.2K resistor for Channel Down, in series with 3.9K for Channel Up. Manufacture used precision resistors here for UP/DOWN. For mic mods I'm sure you'd be fine with 5% resistor tolerance.
BLUE wire- Ground, can be clipped internally on the radio to reuse for other purposes.
WHITE wire- Mic, also supplies around 6-7v to electret microphone. Use bypass capacitor here for dynamic mics.
Post by HighMountainRadio on Mar 4, 2018 8:00:40 GMT -6
Thanks Kage !
This is good to know as I am not particularly thrilled with the stock mic audio quality .. I will have to look around for a good alternate mic.. Any suggestions ? Thanks very much ! Spooky..
"Knowledge Is Always Made More Valuable By Sharing It With Others !" Always Remember To Be Kind ! True Greatness Often Has Very Humble Beginnings ! Help A Kid Out Today ! *** High Mountain Radio *** "Broadcasting From Somewhere High In The Remote Appalachian Mountains"
Any amplified mic will work with a little conversion. You will need to place a capacitor, say 1uf, between the mic amp board output and the radio mic input since the radio itself is designed for an electret mic.
If you find a normal electret mic for another radio it should work fine with this radio as is, just needs rewiring. Even the microphone that comes with this radio can be modded by taking the electret capsule out and replacing it with something a little better but YMMV.
I think I said this elsewhere but a good mod is to open the original plastic mic hole a little with a small drill bit or dremel tool, take the spring out from the PTT button since the switch itself has its own spring to ease up the button press and springy noise it makes releasing it. I've already used my old Courier BTM-4 amplified desk microphone with this radio, only conversion needed was the capacitor to convert from electret to dynamic or amplified mic types and on air checks confirm it gives the radio a little more umph for modulation. Only issue is mics without a channel up/down button will need the buttons added, but with a little modification it's not terribly hard to do.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
