... old times as radio amateur, DC3..

Here some pics when still at high school:


All equipment proudly home-designed and built with little more than a multimeter, a soldering iron and a hand-driven drill:


To the left, a 144Mhz SSB transceiver (ca 30W) and a 432Mhz transverter (ca 2W), to the right a transverter to 1296Mhz (ca 1W). Some extra power amplifiers were used for the 432 and 1296Mhz bands (with the tube 2C39BA). That was sufficient for doing satellite communications via OSCAR7.

My special interest was in UHF/SHF microwave stripline circuitry, like low noise preamplifiers: