I went to very interesting IET meeting last night entitled ‘Enigma & Friends’ given by John Alexander. He is a private collector of encryption machines; the bulk of his collection is currently house in the Block-B exhibit at Bletchley Park and is open to the public.
The difference between going to the museum and seeing his presentation is threefold. Firstly the you get his extensive knowledge of the subject, but I think even more interestingly hear of the adventures it takes to obtain what must be remembered were (or still are) top secret machines. And finally you get a chance to handle the machines, probably something I will not get the chance to do again.
So what did I learn - Russian cold war cypher machines are improbably heavy, and you can buy anything on eBay!