The Russian PR-56A receiver was part of the RION radio set, but was also used on its own. Here you can see the stand-alone version mounted in a special metal frame in a suitcase.

At the beginning of the video, the heater voltage (green mark) and anode voltage (red mark) are checked. The heater voltage should be 1,2 V and the anode voltage 80 V. In the video, the PR-56A receiver is supplied with 1,2 V from a power supply unit and 70 V from several 9 V batteries. This means that the anode voltage is slightly too low, but the receiver works perfectly.

The video shows slow tuning over the 49 m radio band. Many European radio stations can be heard.

Current consumption:
- 1,2 V: 500 mA
- 70 V: 15 mA

The PR-56A receiver is normally operated with headphones. For the video, an active loudspeaker was connected for demonstration purposes.

date: 5th July 2024
time: 20:00 UTC

Links:
PR-56A clandestine receiver: https://www.cryptomuseum.com/spy/rion...
RION spy radio set: https://www.cryptomuseum.com/spy/rion...