X Lock

[Yorkie]

Seems you get a built kit for £33.

Been used in several SW receivers http://www.cumbriadesigns.co.uk/x-lock_solutions.htm but prob solid state

Gary

They're amateur radio transcevers, and with the exception of the excellent Elekraft US K1 kit transceiver, are from the late 70s/early 1980s, several of which - though employing a lot of solid state devices, have valve power amplifiers on the transmitting side, usually consisting of a driver valve, typically 12BY7A, and a pair of 6146Bs. Good in their day, but due to the heat generated by the valves, noted to drift. That wouldn't matter iif it was just the receiver side as it's no big deal to just tweak the tuning knob to sfollw the received signal, but of course, the transmit frequency drifts too, so anyone in contact would have to follow the signal up and down the band, so frequency stability bcomes an issue.

Cumbria Designs is a well know and well regarded firm in the amateur radio 'QRP' (low power) fraternity, (the last refuge of 'homebrewers' in amateur radio), and their units often features in homebrew designs in 'SPRAT' , (G-QRP Club quarterly magazine - an acronym for Small Power Radio Amateur Transmitting'), as it get over the challenge of building a stable VFO. It seems that owners of older hybrid transceivers are also employing this keenly priced module to good effect.