[ARC5] The not-so humble BC-221/LM-xx frequency meters. - zero-beating with WWV

[Arden Allen]

I'm more interested in Howard's question about frequency standards in 
general.  Just how did NBS come up with frequency standards before the age 
of atomic time standards and digital counters?

Arden Allen
KB6NAX

He who is cruel to animals becomes
hard also in his dealings with men.
We can judge the heart of a man by
his treatment of animals.
—Immanuel Kant