[Collins] COLLINS R388/51J-3 SSB CONVERSION OR USE A MODIFIED CE SIDEBAND SLICER?

[Dr. Gerald N. Johnson, electrical engineer]

The CQ articles I referenced from April and December 1968 cover several
mods, including product detector and AGC, and those two appear to be in
the 51J3 I acquired last fall and work very well. I'm working on getting
those articles complete through interlibrary loan at my local library
since I've not held enough good articles in CQ magazine to justify
subscribing or keeping the magazine. These articles are not on the
internet, and the references to them are incomplete. I gave the complete
references with page numbers that make librarians happier hunters.

Apparent frequency error is easily introduced by having the BFO away
from 500 KHz.

The IF output jack is there for using an external product detector
without receiver mods. Most likely a CV-... I don't see any good reason
the CE sideband slicer might not be made to work. Its probably a phasing
circuit so the IF or BFO phase shift will be the critical part to make
it give decent sideband rejection on both sidebands.

I find this 51J3 has adequate SSB selectivity with the crystal in the #4
position and the crystal phasing control set for the best unwanted
reject. Not like a mechanical filter, but it doesn't ring either.

There has been at least one solid state external product detector
available and I have begun to sketch circuits for another, but other
projects will keep it a year or two away.

73, Jerry, K0CQ, Technical Advisor to the CRA
-- 
Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.