Have you checked the SKTF which is on line some where.  Try googling
Smith Kettelwell Technical File 
 


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BRETT WINCHESTER
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208-639-8386
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-----Original Message-----
From: For blind ham radio operators
[mailto:[log in to unmask]] On Behalf Of Jerry Neufeld
Sent: Saturday, August 04, 2007 7:03 AM
To: [log in to unmask]
Subject: circuits for auditory gimmicks

Good morning folks.

I'm looking for detailed circuit descriptions for both relative pitch
and null-producing auditory chopper circuits for obtaining precise
readings of analog meters. The summaries as appeared in recent issues of
QST are insufficient except for the unit used with the MFJ 209 antenna
analyzer. 
Optimally, I could get my hands on the descriptions that appeared in Bob
Gunderson's Braille Technical Press that were first published in the
middle and late 1960's. I would be pleased to purchase the entire
collection or parts thereof if anyone cares to part with them.
Alternatively, I would be very pleased to get detailed descriptions for
the two above-mentioned devices if anyone would care to forward them to
me.

Thanks much for any help here.

Jerry  VE3QSO