[HBR] Frank Jones' Super Gainer

[Ron Barlow via HBR]

Hi Brian,
 Thank you very much for the .pdf Super Gainer article copy!
 Like you, I have always found the Super Gainer to be an interesting concept!

 My guess regarding the reason for the mediocre AM performance, would be insufficient overall gain, preceding the (second) detector stage. 
 This 1957 version includes both an RF and IF amp, as opposed to the early (1930s) versions that include neither.
 That said, the grounded grid triode RF amp wouldn't provide much gain, and the triode mixer would not provide as much gain as a pentode mixer. The older versions used regeneration in the frequency converter first stage, which may yield more overall gain than the non regenerative mixer stage, plus grounded grid RF stage, that is used in the 1957 version??

 I suspect that altering the method of switching off the crystal filter, for AM use, may improve the AM performance. Utilizing the entire IF transformer secondary winding, instead of only 1/2 of it, when receiving AM signals, would increase the signal voltage applied to the IF amp control grid.

 Another possibile improvement would be to make the IF stage regenerative. I believe that this would be easier to use, than a regenerative mixer, as the regeneration level would not change, when the receiver was tuned across the band, or switched to another band, as would be the case with a regenerative mixer.

 GL with your project, Brian!!
                               73 de Ron  n4gjv

  
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On Sun, 9/14/14, Brian Burns <brian at lessonsinlutherie.com> wrote:

 Subject: [HBR] Frank Jones' Super Gainer
 To: "'HBR Receiver List'" <hbr at mailman.qth.net>
 Date: Sunday, September 14, 2014, 3:16 PM
 
 Hello All,
 
  
 
 I've been attracted to Frank Jones' "Super Gainer" that's in
 the November
 1957 issue of CQ. It was his last version of that popular
 simple superhet
 design. I've been searching the literature of the period for
 a couple of
 years looking for a CW-AM receiver design that's actually
 useable on the
 air, and this one comes close to being within my pay-grade
 as a builder. The
 only thing stopping me is Frank's caution that AM
 performance is mediocre.
 
  
 
 Would anybody have suggestions for improving its AM
 performance? I can email
 you a .pdf of the article, if you don't have it.
 
  
 
 Cheers,
 
  
 
 Brian Burns