Time for initial tests

A project log for Shortwave Crystal Radio - A blast from my past

Building and tinkering with crystal radios goes back to my childhood of the late 1960's and coming round again.

Dr. CockroachDr. Cockroach 02/29/2020 at 12:040 Comments

Well, I have finished the construction of the radio and since I have yet to put up a decent antenna, I want to at least test to see if the tuned circuit and detector will sniff out a RF source of some kind.

I do have a simple crystal test circuit wired up on perf board from years ago and if I have it oscillate at say 7.04 MHZ and modulate the RF, I should be able to hear the modulation in the earphone.

Going old school and brute force method and modulate the Oscillator by placing a small audio transformer in the 9 volt power lead then feed the transformer with a audio source from the laptop. Not the best way to do it but it is what it is :-)

Two Hours Later.......

Success, I was able to generate a modulated RF signal at 6, 7 and 11.155 MHZ and calibrate a rough dial. The tuning was fairly sharp and the variable coupler works like it should as well :-)