This was the first czech, officially made "everyman's radio" - CB. In those years, about 1965, there appeared first foreign cheap CBs, mainly from Japan and HongKong. The political direction in the former Czechoslovakia was "sustain comparable", thus, TESLA became a development order for such a radio. The main design criteria was a low price and conformity with the comms regulation of those times in CZ (AM, up to 1W, single rod antenna no longer than a 1,5 meter).

The design result was not very good, even poor, if I can say. The only one noticeable design result is the outfit design, in "warm colour plastics" combined vith high-polished metal - the style of the sixties (Brusel era). At the other hand, the circuit design is as cheap, as possible and the performance is relative to that. The only one germanium HF transistor works as a crystal controlled solo oscillator at transmit, and as an LC tuned regenerative receiver at receiving. Next, there is an ordinary three stage AF amplifier with an output transformer, used both at transmit and receive. The output transformer is used as a modulation choke, too. The radio power output is no more than 100mW, 20 mW typically. The sensitivity of the receiver for a "readable" signal is about 10uV, but, the RX frequency stability is very poor and can vary in hundreds of kHz.

At a practical use, the performance was very poor, the maximal achievable range was some hundreds of meters. The regenerative reciever was directly coupled to the antenna, thus, produced very strong parasite radiation while receiving. The mutual influence of the radio's regenerative recivers made them unusable, if located closer, than about a twenty meters each other. But for those years and for young boys, it was a famous dream ...

All photos are © OK1UHU, 2013