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QRP Station => Builder's Corner => Topic started by: vu2nan on August 19, 2019, 16:26:18 UTC

Title: A Chance Crystal Radio Project
Post by: vu2nan on August 19, 2019, 16:26:18 UTC
A vintage unmarked inductor/transformer had been lying neglected in my junkbox for decades and I had to resurrect it.

Resistance checks showed that 2 windings, with a tap each, are terminated in its 6 pins. One measured 70 Ω with a 5 Ω tap and the other less than 1 Ω. A threaded core, with a movement of 5 mm is situated at the top of the unit.

The 70 Ω winding appeared to be suitable for a crystal radio. It was wired up as per the schematic shown below.

More details at