How we built the receiver
As I also have work responsibilities, we switched to a two-week appointment system for two lessons. Despite the promise, the premises in the school were again just a classroom without the possibility of any mechanical work. That's why I decided, that we build one receiver, but yes, so that the boys understand the origin of the structure and do at least some mechanical work themselves.
I chose to connect a feedback audio with an integrated NF amplifier. Thanks to Braň, we had manufactured printed circuit boards and some parts. I prepared the mechanical parts, so he cut and bent the sheets on the chassis. Gradually, the boys drilled printed circuit boards and holes in the chassis. Because I don't own a tool rental, work went relatively slowly and that was the main reason, why only the most patient endured.
In total, we completed three receivers at the end of the ring. It's not enough, but at least three boys like – so they mastered the basics of electronics. The receiver has been designed for medium waves, but nothing prevents its use on other ranges. The biggest problem was rotary capacitors, we used them from old transistor receivers with the system of who got what. The result can be seen in the pictures 1 a 2. On the picture. 3 is a diagram of the receiver with a breakdown of the components used, and FIG. 4 a 5 is a printed circuit board and mounting plan.
Miro, OM3CKU
