Behold, Bob Monaghan signalled from keyed 4-1000A filament:

snip

my $.02 ;-)

bobm

Very well put Bob!

Ah, yes. Growing up to Forrest Mims books was the cat's meow of DIY of
the time :-)

--
Gregg t3h g33k
"Ratings are for transistors....tubes have guidelines"
http://geek.scorpiorising.ca