I heard again about the 'silent key', and was reminded that an Electronics instructor of mine in a local college was a fan of the paddle key as a Ham radio operator.   I'm left wondering and on a mission to find out if he is 'silent key' or still alive.  This graduating class was 30 years ago (1995), and he also taught me to use the 8080 processor assembler, which the chip could only be re-written after erasure from exposure to a UV light.