[Heath] IG -57A schematic received

[G3OOU at aol.com]

In a message dated 19/03/2012 17:19:12 GMT Standard Time,  
donley.dn at comcast.net writes:

I am  intrigued by your stated project - 'a "high-performance" crystal 
tester  
and evaluator'. I have been searching for the ultimate, all-encompassing,  
all-frequency crystal tester. I would appreciate any information you could  
share on this project. Most testers that I have found have holes in the  
frequency ranges that they  test.

73
Richard
kc9ub



Hi Richard
 
I use a Type 193a Crystal Activity Meter for fundamental parallel resonance 
 crystals which dates back to WWII and does fairly well. I have made 
several  attempts to do a solid state equivalent but none work as well as the  
original.
 
STC in the UK made a series resonant test set many years ago but I  have 
never managed to get my hands on a circuit diagram.
 
73

Bob

Bob F Burns
C Eng,  FIET, MSE
Amateur Radio Callsign: G3OOU
Registered RSGB  Instructor
G-QRP Member No: 6907; Zone: 14, QRA: IO91WH; WAB:  TQ25
Secretary of Crystal Palace Radio & Electronics Club: _www.g3oou.co.uk_ 
(http://www.g3oou.co.uk/) 
Technical web site: _www.qsl.net/g3oou_ (http://www.qsl.net/g3oou) 
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