[Milsurplus] NAF 68304 Nay Beam Filter

[Bob Camp]

Hi

If you take a look at the "state of the art" for generating audio  
tones back then - an ac motor driven ac generator was a very common  
answer to the question. A direct coupled shaft would have been the  
first choice.

Bob


On May 31, 2007, at 11:15 PM, Al Klase wrote:

> D C *Mac* Macdonald wrote:
>> I am not absolutely certain, but I believe that the tone
>> frequency used was actually 1020 Hz, supposedly because
>> research had shown that a tone of that frequency gave
>> the strongest response in the average human ear for a
>> given actual sound pressure.
>>
>> Mac, K2GKK/5
>> Oklahoma City
>
> I don't know about that, but 1020 is an even multiple of 60Hz  
> making it easy to calibrate from the AC line frequency.
>
> Al
>
> -- 
> Al Klase – N3FRQ
> Flemington, NJ
> http://www.skywaves.ar88.net/
>
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