[Boatanchors] How did they "pinpoint" frequencies way back when?

[Robert Nickels]

> There was a reference to some kind of mechanical engine for making BC-221
cal
> books on a list (perhaps this one) a couple of months ago.

Well my friend John is correct, as a simple Google search would have proven
before I opined to the list. So for those who also wondered how the BC-221's
were calibrated, prepare to be impressed!  Thanks to Philco for figuring
this out, and to Jerry Proc for making it available:

http://webhome.idirect.com/~jproc/ve3fab/bc221.html

73, Bob W9RAN