Today I finished building a 50 Ohm/20 Watts dummy load on a perf board using 20, 1 kilo ohm, 1 Watt resistors connected in parallel. I need to search for a suitable diode to use at the output to build a rectifier at the load, so that one could measure the voltage drop across the load with an ordinary multimeter, but I could not find one on my junk box at the moment. Mastodon user "digger AB3XU" pointed me to an interesting but more complicated dummy load design today when I announced my build and it looks very tempting.