[Elecraft] Astatic D104 mics

[Don Wilhelm]

Steve,

The amplified D-104 should work just fine as long as the gain 
potentiometer is set correctly.  The K3 ALc display should be helpful in 
arriving at a setting that will work with the K3 mic gain set for a 
mid-setting.

The answer for the unamplified D-104 is "it all depends".   The 
frequency response of the D-104 crystal or ceramic mic elements depends 
on the load resistance, and the design response needs a 50k to 500k load 
resistance - the K3 provides a nominal 600 ohm impedance, so the D-104 
will sound 'tinny' if connected directly.

There are those who say that a series 100k resistor in the AF line is 
all that is needed, but I have not tried that.  The D-104 microphone 
that I use has an FET in the base with a 470k resistor across the gate 
to load the microphone and a sufficiently low output impedance to 
provide a good mic gain range for the K3.

73,
Don W3FPR

On 10/7/2013 7:15 PM, Steven Bertsch wrote:
> I have a friend who is getting two D104 mics. One is an amplified mic (9 volt battery in the bottom), and the other is not. Will they both work with the K3/0? Do any changes need to be made in the MENU settings? He will be using them to remote into my K3/100.
>
> Any suggestions would be greatly appreciated.
>
>