[ARC5] SCR-522 components

[Mike Everette]

Believe it or not, the receivers were much easier to convert than the transmitters.  QST and CQ published articles on doing this during the late 40s and early 50s.  It was not that difficult to make them tunable and bandspread the tuning to cover the 2 meter band.  Notice, I didn't say it was quick and dirty; this did require some disassembly of the equipment and of the receiver front end to avoid breaking the ceramic shafts in the tuning capacitors when removing plates to accomplish the bandspreading. 
My 522 receiver, so converted, had a squelch-opening sensitivity of about one microvolt on AM.  I later grafted an FM bandpass filter, second IF and detector from a Motorola packset receiver into it, using the first 2 stages of the 12 mc IF in the 522 as intended and rewiring the third one into a crystal-controlled converter using a 12SA7 to take that IF down to 455 kc. The result had amazing sensitivity, less than 0.3 uV if I remember right, but was very susceptible to drift from air currents in the room.
Putting the receiver section into a case from a BC-375 tuning unit helped somewhat.
I learned a lot from the 522.
73
Mike
WA4DLF    

      From: Cliff Miller <cliff52 at gmail.com>
 To: ARC5 at mailman.qth.net 
 Sent: Tuesday, August 8, 2017 9:53 AM
 Subject: [ARC5] SCR-522 components
   
I see the second BC-325 transmitter in recent weeks on auction today.  Channel control and jack boxes, even connectors show up regularly.  What happened to the BC-324 receivers?
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