Richard Clark wrote:
....

I've calibrated these too (Boonton, I think, also built them, but as
Boonton was acquired by HP, it isn't a remarkable difference).


Errrk?? From Boonton's web site:

"In July 2000 we became a member of a larger family as we were acquired
by Wireless Telecom Group, Inc. (doing business as Noise Com). Being a
wholly owned subsidiary of Wireless Telecom Group, Inc. has enabled us
to further our product development and customer service initiatives."

See http://www.boonton.com/2002/about-history.html