Re: uBITX Mic Wireup

Arv Evans


You are right on.  Since the electret microphone uses a microphone voltage
resistor inside the uBITX or BITX-40 (or any older BITX with electret microphone)
it is possible to sense voltage drop across this resistor (with a MOSFET...?)
and key the transceiver when the microphone circuit is closed.  This is for
those who are wondering how to connect a 2-wire electret microphone with
built-in PTT switch. 

This is particularly useful for those cheap combination ear-buds and electret
microphone that we see in the Dollar Stores. 


On Sat, Mar 10, 2018 at 1:04 PM, Dexter N Muir <dexy@...> wrote:
Fanciful, perhaps, but would it be possible to detect the current drain of the electret as a PTT? Enough resistance in the feed resistor of the rig should take the electret voltage down to mid-supply - detect that.

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