On 9/10/2011 6:23 PM, Mike Morrow wrote: > Plus, an LM or SCR-211 frequency meter would be essential. There > is no real calibration data provided for the TA-12 and RA-10. Bendix sold a frequency meter that they called an IF-12, which looks suspiciously very, very similar to a BC-221. The same thing in a rack mount was called an IF-9. Jack Antonio WA7DIA/4