K3 Microphones

[kd1na]

Hay Elecrafters,

Got a question for you.

Why does only certain microphones operate the VOX properly? I have the most recent firmware (downloaded yesterday) installed.

I have 2 different microphones. One is an EF Johnson (manufactured by Shure) which is dynamic and an ICOM desk mike which requires bias to operate.

 Both mikes operate normally in SSB mode with the mic gain around 40 for the dynamic and 30 for the ICOM.


Using the ICOM the VOX works wonderfully. one of the best VOX I have ever used.(VOX Gain set about 40).

Using the dynamic mic with the bias off, despite the fact that I get good audio reports and driving the rig quite well I have to set VOX gain to 100 and have to really shout into the mic to get the VOX to trip.

Any ideas?

Thanks and 73
Dave KD1NA
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[KK7P]

> Why does only certain microphones operate the VOX properly? I have the most recent firmware (downloaded yesterday) installed.

If the MIC GAIN is set such that you are getting 4 to 5 bars of ALC, the
VOX should work consistently.  At least, it has in my testing with three
different dynamic mics and two different electret mics, as well as the
LINE OUT from my PC.

It may be that you have enough audio drive from your dynamic mic to
adequately drive the transmitter but not enough to get 4 to 5 bars of
ALC, in which case the VOX is being under-driven (or perhaps the
anti-VOX is being over-driven).

If this is not your problem, please email k3support and they may have
further insights for you.

73,

Lyle KK7P

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