diy IF transformers: first attempt.

[Ed_Dinning]

Hi Amie, I recently repaired an IF for a battery valve set. These were both wave wound but only about 8mm dia. They sat inside a ferrite cup that had the" base" threaded to accept an adjuster. The centerpiece was stepped (small/large/ small) and also of ferrite and the whole lot was glued together with wax.
The whole lot fitted inside a conventional 1/2" square can.

I have seen (I believe US origin) IFTs that had the 2 winding bobbins at right angles to each other, but I think these used an additional coupling winding (and trimmers for tuning)
There are many weird and wonderful ways to make a tuned filter, if you have the time Electronic Engineering from the 40's has some articles on IFT design and details of coil/ can spacing.
There was also lots of work done in Wireless Engineer in the 30's and the patent office library will have quite a bit of detail on this (not sure how accessible that is these days.

I have plenty of IFs of various sizes if you need any to experiment with.

Keep up the good work and innovative thinking

Ed