[Collins] WTB: 51S1 bottom plate cover and FL-1 transformer

[Dr.Gerald Johnson]

I don't have any 51S-1 information to go on but I can guess.

Good cores were just beginning to be available when the 51S-1 was made 
and some that gave good RF results failed with power applied. The line 
current saturated them and then they didn't filter RF. So coreless filters were 
used, requiring larger capacitors for adequate filtering. And today those larger 
capacitors probably draw enough current to annoy GFCI circuits. Those filters 
with cores may not draw so much ground current but its a matter of individual 
design.

I remember in the early to mid 60s, that ferrite cores were rapidly improving in 
all characteristics and the 51S-1 was designed before I began working with its 
designers.

One time in the lab, my boss caught me drooling over a 51S-1. I told him I was 
in the market for a receiver. He told me he was in charge of the design of that 
radio and that a 75S-3B with a crystal pack was a superior receiver. That I 
shouldn't spend my money on the 51S-1. So I did buy a 75S-3B later that year 
and the crystal pack a few years later.

73, Jerry, K0CQ

-- 
Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.