[David G4EBT]

As mentioned in post #7, Dr David Tong, (now professor David Tong) formerly of the long since defunct company Datong, is very much alive.

He's a quantum physicist and Cambridge Professor.

As such, as economists put it, you should 'maximise your comparative advantage' and I guess that has been his direction of travel in his stellar career. So if you're a brain surgeon, get a gardener to mow your lawns - don't do it yourself and squander your talents. Given his talents, it would make little sense in terms of productive use of his time, or in income terms, to be designing and marketing ancillary products for the very limited amateur radio market. The Datong Morse Tutor was an excellent device, but of course, for the few who bother these days, there are online Morse tutors such as the excellent G4FON Morse Trainer, so little market for a hardware tutor.

It's intellectually-challenged long since retired old buffers like me who can indulge in the luxury of tinkering around from one day to the next, on time-consuming trivialities restoring old radios and woodturning, in an effort to enjoyably while away as much of what's left of my life as possible.

Even back in the 1999 RSGB Year Book, (the most recent one that I have), David Tong's call sign had lapsed, but his wife's was still there, and indeed, on just checking the Hamcall Database, it's still listed at an address in West Park Leeds, though her data, like mine, hasn't been updated in the last five years so I assume that she's inactive on air. (Same applies to me - a 'RHINO', Radio Ham In Name Only', last on air in 2003).