[Milsurplus] NAF 68304 Nay Beam Filter

[D C *Mac* Macdonald]

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



----Original Message Follows----
From: Bob Camp <ham at cq.nu>
To: w1eof at hamnutz.com
CC: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] NAF 68304 Nay Beam Filter
Date: Thu, 31 May 2007 21:42:34 -0400

Hi

Back before there was dirt, they had a navigation system that put a  1Kcps 
tone on an AM signal. The signal also carried voice information.

The filter went between the radio and the headphones. You could  switch it 
to "beam" for the navigation signal (band pass), to "voice"  for the 
information (notch) or to "both" (pass).

Bob
KB8TQ


On May 31, 2007, at 9:07 PM, Mark W1EOF wrote:

>Navy Beam Filter NAF 68304
>
>Anyone got any info on this? Where it was used? Purpose? Where can  I 
>locate a book or at least a schematic on it?
>
>Thanks guys!
>
>Mark W1EOF
>