[Collins] Mic output levels

[Dr. Gerald N. Johnson]

On Tue, 2006-10-10 at 11:46 +1300, Dave Brown wrote:
>  I note that Collins mics are typically specified as having -50 dB 
> output but what is the reference voltage level and is the mic output 
> specified open cct or loaded-if so, with what?
> 
> 73
>  Dave, ZL3FJ
> 
That's probably power with respect to 1 milliwatt and so the
corresponding voltage depends on the impedance the microphone is
made/connected/set for and while the microphone is loaded with its rated
impedance whether its a 600 ohm dynamic microphone or a 1 megohm crystal
microphone.

Looking at the tests for a 32S-3A, the microphone input gets 35
millivolts, to a 100K load. 12 nanowatts. And that is -49.118 dBm.
-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer