The legendary czech military receiver of the sixties. Primary designed as a part of "Třinec" radio set, this receiver was very wide spread in the Czech army in those years. The receiver is a classical superheterodyne model, based on not very special tubes 6F31. It has a tuning range 1,5 - 12,5 MHz, good sensitivity, variable IF bandwidth, tunable BFO and can drive headphones, speaker and 600ohm line.

The power supply is in a separate box, the first version uses dynamomotoric voltage changer, the newer ones use a transistor SMPS. I both versions, there is a possibility of mains (220V) supply, the mains transformer and 6Z31 rectifier tube is included.

In a real traffic, the tuning is slightly rough, thus, it needs som patiency at the weak signals. The BFO works in additive mixing, thus, CW reception is flawless, but SSB reception is a matter of trick. There is a mod available to rearrange the BFO mixing form additive to multiplicative, allowing much better SSB reception.

There is some support information, concerning this receiver, on my web, too. Feel free to enjoy it:

All photos are © OK1UHU, 2011