[Elecraft] Need Pinout for Heil HMM "icom" hand mic

[Don Wilhelm]

Rick,

Grab the KSB2 instruction manual and look at the wiring for Icom 
microphones.
Since you are using a Heil mic (with an Icom adapter), you only need to 
be concerned about the AF pin, the PTT pin, the AF Ground and the PTT 
Ground - connect those pins on the K2 microphone configuration header - 
Heil mics only implement those 4 signal lines.

Since the Icom rigs apply bias to the AF pin, you need a bias resistor 
from +5 volts to the Mic jack AF pin.  Usually a value between 5.6k and 
10k will work, but if you need the best value, contact HeilSound and ask 
for the recommended value for the Icom element from a +5 volt rail.
If I assume that the Icom element in that mic is the same as in the 
Elecraft ProSet K2 or MH2, then 5.6k is the best value, the that is one 
assumption too many - best to ask HeilSound about that.

73,
Don W3FPR

Rick Tavan N6XI wrote:
> I need to connect a Heil HMM "for icom only" mic to a K2. The KSB2 and Heil
> Website don't mention this mic. The pinout is not the same as the
> Heil-manufactured Elecraft MH2. The mic has a handwritten label "PTT 5&6"
> and I have confirmed that this is correct. How do I jumper the mic pin block
> for audio (pin 1?) and 5V? What value bias resistor should I try?
>
> Thanks,
>
> /Rick N6XI
>   
>