[Elecraft] K2 Experience with SM-8 and Heil HM-I Microphones

[Don Wilhelm]

Doug,

You must decide how you want to wire the K2's microphone configuration 
header.

If you choose the Icom configuration, your Icom SM-8 microphone should 
work fine - just plug it in.  If you choose the Heil mic (any of the 
Heil mics), order the adapter that matches the way you have the K2 
microphone header wired - in other words, if you have the K2 wired for a 
Kenwood mic, order the Kenwood adapter, if you have the K2 wired for an 
Icom mic, order the Icom adapter, etc.

Whether you need a bias resistor from 5 volts to the AF pin depends on 
the mic element.  If it is a dynamic element, no resistor should be 
installed, but if it an electret element, you will need the bias resistor.

The two conditions - mic header wiring and the bias resistor are two 
separate issues - the wiring (except for the bias resistor) depend on 
the mic plug pinout, the bias resistor depends on the mic element type.

Most Heil mics for the Icom (-iC suffix) are electret types.  If you are 
not certain, an email to Bob Heil can clarify the element type.  For 
element types of the other transceiver manufacturers, your best resource 
is to ask the manufacturer of the microphone about the element type - we 
can guess, but guesses leave a degree of uncertainty.

73,
Don W3FPR

Doug Person wrote:
> I'm just about complete with KSB2. I'm thinking of setting the K2 up 
> for either the Icom SM-8 or the Heil HM-I mics.  Looking at the chart 
> on page18 of the assembly manual - neither are listed.  Does anyone 
> know if the setup for these mics is the same as the other Icom mics 
> shown in Table 2?
>
> Doug -- K0DXV
>