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[AMPS] Bandswitch ramblings...

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Subject: [AMPS] Bandswitch ramblings...
From: (Radio WC6W)
Date: Wed, 5 Sep 2001 13:55:19 -0700
Hi everyone,
  I've been contemplating the bandswitching for a new amplifier project
with a Pi-L output network and I'm just not enthused by the traditional

  The input will also be tuned with a 9 position switch coupled to the
output tuning so, the output switch will also need to have 9 positions
even though 6 or 7 taps will suffice to cover all the bands. 

  A (actually two) big rotary switch(es) with a nest of straps just seems
so cumbersome.

  Plus, I've been thinking that it would be nice to connect all the
unused portions of the coils to their respective ends.

  My solution of the moment is to make a scaled up version of the cam &
leaf arrangement used by Tektronix in some of their test equipment of the
1970-80's.   If you haven't seen the insides of one of those, it
resembles a music box mechanism.  And if you haven't seen the insides of
a music box, I'm out of analogies.

  A feature of this arrangement is that the contacts are all arranged in
a line which may be placed adjacent to the Pi (or L) coil for short
direct connections.  And by proper shaping of the cams, all the unused
coil sections may be connected simultaneously.   A shaft and index
section from a "standard" rotary switch affixed to the end of the cam
will provide detents.
   Has anybody ever seen like this in an amplifier?  Thoughts? 
Suggestions??  ... Criticisms???  :-)

  Marv  WC6W  


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