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Monday, June 13, 2016

Inside a Millen 61455 IF Transformer


I found this in my junk box.   I've put it in my old Mate for the Mighty Midget receiver, in the place of the Toyo  CM455 crystal-mechanical filter (which I found to have excessive insertion loss).  I think its very cool how they squeezed two variable caps into that little can.  Designed in 1956.  Works great.  Note the promised passband: 4.7 kc at 6 db down.  Not bad for an LC device.
Here is the spec sheet:


 

2 comments:

  1. neat! Wondered what 'other' tech might be found in them things. Most seem to be permeability-tuned. There's fine design and engineering in those too, e.g. split tapered threaded studs with lock nuts. My eyesight was never good enough to determine which was tapered - the stud or the nut :), most likely the nut. there were cheaper ones too - Philips tended to spring-wire whisker for enough friction to allow initial tuning (and incidentally avoid the need for threading the can), then 'Loctite' or wax to (sort of) seal it.

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  2. Cool Bill! That's truly an RF "can".

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