The Frequency Meter Set SCR-211-(&) is a precision instrument designed to measure or radiate radio frequency impulses between 125 and 20,000 kHz. It is portable, completely self contained instrument used mainly to calibrate field radio receivers and transmitters by direct comparison with the calibrated variable frequency oscillator of the frequency meter. Each meter contains a 1,000 kc crystal oscillator circuit with is used both as a source of accurate radio frequency signals at multiples of 1,000 kHz and for calibrating the variable frequency oscillator of the instrument at a number of points. These points of frequency calibration are called "Crystal Check Points".
BC-221-B, -E, -N, -Q, -AA, -AE, -AG
BC-221-A, -C, -D
BC-221-F, -J, -K, -L
BC-221-M, -O, -P, -R, -T, -AC, -AF, -AH
the BC-221 were designed to operate on batteries, however there are several designs for a AC power supply that can be used (RA-133 installs inside the battery compartment.
- TM 11-300
- Frequency Meter Sets
- SCR-211-A, -B, -C, -D, -E, -F, -J, -K, -L, -M, -N, -O, -P, -Q, -R, -T, -AA, -AC, -AE, -AF, -AH, -AJ, -AK, -AL
- 20 July 1944
- Building a Power Supply for the BC-221
- CQ Magazine
- April 1959, PP79