[Milsurplus] BC-221-J vs BC-221-T or what?

[Hubert Miller]

Somewhat re the recent het freq meter discussion, i was just randomly 
pawing thru U.S.N. 'Electron' from 1948, and i read,
14% of transmissions from Navy ships were beyond the 0.02% frequency 
tolerance expected. At 10 MHz, that's more than
2 kHz off. The recommendation is to be sure your frequency meter is 
calibrated against the WWV standard.
-Hue Miller