Short-wave telegraph transmitter Tesla KTV 50 + its power supply

This transmitter could be tuned from 6 to 19 MHz. Such a big band width enabled the use of a suitable frequency depending on the desired direction of connection, the day time and the season of the year. If all the conditions are correctly fulfilled, the short waves make it possible to communicate across thousands of kilometers. This transmitter was placed in Poděbrady and was used to send messages to diplomatic missions, secret spies etc. It was withdrawn in the nineties.

The transmitter is accomodated to easily change the transmitting frequency, which is essential on the short waves. The coils are placed in a carousel that is controlled via the turning dial on the panel. A motor would automatically turn the carousel to the position selected by the staff. You can also see the controlling circuits of the transmitter. The lights show the operation of all the components of the transmitter, such as the filament heating, anode cooling, the state of switches and protection circuits. If any error happened, such as defective cooling, the transmitter automatically switched off. The circuits also checked that all the doors of the cabinets are closed so the staff cannot be harmed by electricity. If the staff needed to manipulate with the components inside the cabinets, they would have to firstly switch off everything and then discharge the capacitors using a shorting rod.

The power supply provided all the necessary voltages ranging from a few volts and several amperes for the filaments to thousands of volts for the anode circuits. The power supply was modified in the seventies - the original mercury vapor rectifiers were replaced with semiconductor diodes. The capacitors are of paper-oil type. If any of the capacitors failed, it would easily explode and start a fire.