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:
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.
Thanks for sharing Bill. That is a neat centerpiece for your receiver. I think it would be neat to build a modern transceiver using older technology. I’ve been thinking about rolling my own IF transformers. Now I have the inspiration and a basic design. All I need now I just need a workshop. Please post a video of your receiver working with the transformer. 73’s Dean AC9JQ
Cool Bill! That’s truly an RF “can”.