[Craig Sawyers]

I missed the AR77. But the main bank of receivers are definitely (currently) AR88's. They have a bunch of old boys there who know AR88's forwards and backwards that keep them going and restore replacements when needed.

They have replicated the "undulator". That produced a printed trace of the incoming morse stream from the intercept. Almost looks like a continuous oscilloscope trace on a long strip of paper. A group of women then interpreted the undulator paper tape and typed out the Baudot punched tape needed for Colossus. All labour intensive - but anything to do with code breaking was tough in one way or the other.

There has long been a suspicion that there are more SZ42's out there. The only known complete ones are the BP one, and one at the National Cryptologic Museum in Maryland USA. The only partial one I know of is the Norwegian one currently on loan to TNMOC. And the suspicion is that they are some in the ex-USSR, probably now owned by rich oligarch collectors. But there never was many made or used. The German standing order was that if you anticipated capture, destroy the machine. Throw it in the sea, or blow it up. So a relatively small number was reduced further.

I have a paper somewhere written by a German comms unit officer. The Russians were just about to take over that area. So he put his SZ42 in a bomb crater, packed it with explosives and lit the fuse. He then has to stop anyone diving for cover into that particular crater!

Craig