Since I also have work obligations, we switched to a system of meetings once every two weeks for two teaching hours. Despite the promise, the school premises were again just a classroom without the possibility of any mechanical work. Therefore, I decided to build one receiver, but in such a way that the boys would understand the construction and do at least some of the mechanical work themselves.
Zvolil som zapojenie spätnoväzobného audiónu s integrovaným NF amplifier. Thanks to Braňa, we had printed circuit boards and some of the components made. I prepared the mechanical parts, i.e. cut and bent the sheets on the chassis. Gradually, the boys drilled the printed circuit boards and holes in the chassis. Since I don't own a tool rental shop, the work went relatively slowly and that was the main reason why only the most patient ones lasted.
In total, we finished three receivers at the end of the group. It's not much, but at least three boys somehow mastered the basics of electronics. The receiver was designed for medium waves, but nothing prevents its use on other ranges. The biggest problem was the rotating capacitors, we used them from old transistor receivers with the system of who got what. The result can be seen in pictures 1 and 2. In picture 3 is the diagram of the receiver with a breakdown of the used components and in pictures 4 and 5 is the printed circuit board and the mounting plan.
Miro, OM3CKU