BC-221

Overview

The Frequency Meter Set SCR-221-(&) 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-AJ, -AL

BC-221-M, -O, -P, -R, -T, -AC, -AF, -AH

Power Supplies

the BC-221 were designed to operate on batteries, however there are several designs for a AC power supply that can be used.

Images

• BC-221-AH
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Reference Files

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