[Collins] Using an AStatic D-104 with Collins rigs

[Barockteer at aol.com]

It's a simple matter of impedance matching...

The D-104 crystal element nominal output impedance is very high, above 1 
Megohm. This should have driven the high input impedance of various Collins rigs 
fine, albeit with some rolloff.

The HC-5 mic element has an impedance of 2K ohms nominal. This means it will 
not produce enough signal into the high input impedance of the Collins rigs.

I would suggest you replace the element in the D-104 with a direct 
replacement. You're looking for an MC-320 element. Then, if you want to improve the 
response, increase the input resistor of the rig to 1 Meg or better. 

The best thing I've found is to get a T-UG8 amplified stand. Add a series 
resistor on the input of 1-2 Meg, and carefully adjust the amplifier gain so as 
not to overdrive the rig. I use this and it sounds great, especially with the 
KWS-1 or 32V which have wider bandwidth.You may also be able to use the 
amplifer with the HC-5 element. Or, try to find an audio impedance step up 
transformer.

73,

-Tony