To ensure reliable shortwave communications over whole Switzerland, there was a great demand of high power shortwave transmitters and receivers in the years of World War II. The Swiss Air Force technicians re-used shortwave wireless equipment from U.S. bomber aircraft which had made an emergency landing on Swiss ground.

The receiver part of the U.S. Signal Corps SCR-287, the BC-348, the Swiss variant carries a "H Empfänger" (receiver of "H station") typeplate, comes in a black aluminum cabinet (this to remember, the SCR-287 is an airborne station), it's dimensions are 46 x 23 x 22 cm and it's weight 20 kg.

The receiver is a single superhet with an intermediate frequency of 915 kHz. The RF signal from the antenna has to pass two tuned RF preamplifier stages (two valves 6K7 / VT-86) and is fed to the mixing stage (6J7 / VT-91) to generate the intermediate frequency of 915 kHz with the signal from the main oscillator (6C5 / VT-65). After the IF amplifier stages (1st IF: 6K7 / VT-86, 2nd IF: 6F7/VT-70, 3rd IF: 6B8 / VT-93), the signal is demodulated (diode system of valve 6B8 / VT-93) and fed to the AF output stage (41 resp. VT-48, later 6K6GT). The second triode sytem of the 6F7/VT-70 is used for the beat frequency oscillator for CW reception.

Usually, the Swiss H-Empfänger / BC-348 are operated together with a combines mains power supply and AF / voice amplifier made by Zellweger AG, Uster.

The equipment shown in the images makes part of a Swiss private collection. I would be very thankful for further information and images from an operational H-Station.