[Collins] Mic output levels

[Dave Brown]

Tnx Jerry.  Interesting they seem to have used the 1mW reference 
although they didn't quote the levels as dBm.
Was the 'test' figure meant to be a typical mic output level?   I 
don't suppose you have a test figure for the KWM-2?   I see that while 
the 32S-3 has 100k with 220pf in parallel at the mic input,  the 32S-1 
and the KWM-2 both have 1meg in parallel with the 220 pF.

73
Dave, ZL3FJ



----- Original Message ----- 
From: "Dr. Gerald N. Johnson" <geraldj at ispwest.com>
To: <collins at mailman.qth.net>
Sent: Tuesday, October 10, 2006 3:48 PM
Subject: Re: [Collins] Mic output levels


> 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
>
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