This page contains a downloadable PDF file of the entire SCR211 manual, which covers all models of the BC221 Frequency meter. There are also other files here that will work with both the BC221 and LM frequency meters. Find great deals on eBay for bc221 frequency meter. Shop with confidence. BC221, part of SCR211 Frequency Meter Set. For about half a century BC221 has been used as reference generator or frequency meter in the many communication and ham labs worldwide.
Jul 06, 2015 WW2 BC221M Frequency Meter Set Test Equipment (Complete Set Is Known As: SCR211M) Made by Bendix in 1942. The set required batteries and 1' to 2' length www. w5jgv. com After reading though the manual the BC221 transceiver project was born Instead of just using the BC221 as a transmitter why not use it as a transceiver.
Obviously the BC221 frequency meter circuit is easy to tune, accurate, and develops very little drift and the resulting transmission or reception would be very stable in frequency. The placard proclaims this to be the BC221B frequency meter. The manual says SCR211B Frequency Meter Set. One thing Ive noticed with military gear is that a collection of components grouped into a set receives its The battery compartment occupies the lower part of the frequency meter and opens via a hinged door on the rear of the box.
The circuit diagram of the BC221T is drawn inside the hinged door of the battery compartment. Frequency Meter BC221 Set SCR211 Was designed to provide a simple, accurate, and reliable crystal calibrated frequency indicating equipment for Net operation may be a problem, so the manual recommends using a BC221 frequency meter. The oscillator drives a VT62 (or 801) power amplifier. The plate is fed by an RF (Radio Frequency) choke, and it is capacitor coupled to the matching network.
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. How many BC221's or similar frequency meters do you own? Assuming that your answer is 1 (one) then that is fine. Owning 1 (one) BC221 is normal collector behavior. Then reading the manual I realized that it would be possible to use the BC221 as a transceiver.
Anyway I built