Super-regenerative FM receiver with tubes

Construction example - fun project

Super-regenerative receiver rised a revolution in the reception of VHF waves in the time of its introduction, around 1920. It soon became obsolete. Will it be of any use today?

From its history - Armstrong's Super-Regenerative Circuit

All the main components - tubes, sockets, power and output transformer, come from the remains of a defunct tube TV. The tuning capacitor and speaker come from the remnants of an old transistor radio. No historical electronics were destroyed because of this project :)

The circuit was taken from proven available online sources. I have added only a few minor changes to improve the performance. Due to miniaturization, the filament and B+ voltage is obtained from a single small transformer 31V / 380mA. The B+ voltage of 65V is obtained by a simple diode multiplier from the filament winding. Due to the all-metal miniature design, the use of a higher voltage would be dangerous.

The idea and circuit was taken from following sources:

• https://www.cool386.com/12v_6BL8/12v_6BL8.html
• https://www.cool386.com/6dx8/6dx8.html

Design

Copper cube box with edge of 94 mm. All mechanical elements, box, chassis, tuning mechanism, buttons, were home-made by hand.

 

 

Super-regenerative FM receiver with tubes | copper cube - video of the project on YouTube

 

Please comment on YouTube

 

Super-regenerative FM receiver with tubes | tjprofil.php5.sk, 2020