Pulled out my dummy load tonight

Press image for a better view of the dummy load

Testing a transmitter means the use of a dummy load. Trying to be considerate, I don't want to cause unnecessary interference with my signals. So when I want to test my Ultimate 3 QRSS/WSPR kit I also pull out one of my dummy loads.

It measures just 9-10 mm across and is the size of a BNC connector. It is simply one of the many Ethernet terminations that I have lying around. Its built-in 50 ohm resistor is rated at something like 0.25 W. Considering that the kit outputs something like 200 mW that should mean that there is enough margin and no forced air cooling or liquid cooling is required.

Bletchley Park, Enigma, and GB3RS

Enigma (Photo: R. Holm)

Bletchley Park, northwest of London (between Oxford and Cambridge), is one of the best known British sites from WW2. Its fame goes back to the breaking of the legendary Enigma cipher machine and its successor, the Lorenz cipher machine.

In order to perform this work a large effort in the development of early computers took place here. They include the mechanical Bombe for breaking the Enigma, and the valve-based Colossus for breaking the Lorenz.

The Bombe was reconstructed through a 13 year effort that resulted in an Engineering Heritage Award in 2009.