wrote:
You should be aware that each BC-221 and the other heterodyne
frequency meters had its own individually plotted calibration book so
using one from another meter wasn't an accepted practise.

Still, if you don't have any calibration book anything is better than
nothing.

73,

Michael, W1RC

On Sat, 20 Dec 2008 22:49:15 -0500, "Tio Pedro"
There were some articles regarding BC-221 calibration
in the late 40s early 50s QSTs.

There is an excellent article with photos of the original equiupment
used to calibrate the BC221.It appeared in the Christmas 2008, Issue No.
116 of the UK Publication Radio Bygones. (www.radiobygones.co.uk
www.radiobygones.com)

The article is based on a reference in the May 1944 edition of
"Electronics" (U.S. magazine???)by Philco Engineers which described the
calibration procedure in detail

Those people were really clever!!!

Lionel L Sharp