VHF Radio SE-412/K, VRC-12 resp. VRC-43; Transceiver RT-264, manufactured by Associated Industries.
In the late sixties, American VHF radios were acquired with the purchase of the American armored personnel carrie M113: the system AN/VRC-12 with the transceiver RT-524A later found a widespread use.
The variant RT-264 with ten electomechanical frequency presets and motor tuning was originally not used in Switzerland. Only when the tank 87 „Leopard II“ was introduced, the set RT-246 was introduced as SE-412/K.
The VHF radio covers the military VHF range in two bands (30 - 52.95 and 53 - 75.95 MHz) in 50 kHz steps, the transmitter output power can be varied, in position POWER LOW, with an output power of 1 - 3 W the communication range is approx. 5 km, in position HIGH, with an output of approx. 35 Watts, the range is increaded to 20 - 30 km when the standard whip antenna is used.
On the front panel of the transceiver, the lamp CALL in the left upper corner signals an incoming radio call when the squelch is opened. Below it, the motorized frequency selectors for the MHz and the kHz digits are located, the operation frequency is displayed in the small window of a mechanical digital display.
The SQUELCH switch is located in the lower left corner of the front panel: in the SQUELCH OLD mode, the receiver is activated by an incoming signal, in NEW position by a 150 Hz audio subcarrier from another set of the SE-412/227 family. Right next to it, the volume control.
In the middle of the front panel, the band switches for the two VHF ranges A and B (30 - 52/53 - 75 MHz) and automatic switchover from the remote control in the AUTO position are loacted; below is the operation switch with the positions for low and high transmitter output and REMOTE operation.
To the right, the push-buttons for the ten channel presets are located, the frequencies are preset electromagnetically for each button.
In the right upper corner is the antenna socket. The automatic antenna tuner is connected to the ANT CONT(rol) socket.
For mechanical presetting of the frequencies, the lid of the keypad is folded down. To preset a frequency, press the appropriate frequency button, then press and hold the TUNE button (not too long, due to the risk of overloading coil L 301), with the tiny switches at the left (upper row) or at the right of the frequency buttons (lower row, channels 6 - 10), the band A or B is selected and then, the frequency is adjusted by turning the frequency adjustment screw of the corresponding channel. After releasing the TUNE key, you can change to another channel and select the preset channel again; the unit should return to the preset frequency.
With a C-2724 channel selectorc onnected to the REMOTE connector, the ten channels of the RT-264 can be remotely controlled. The X-MODE connector is provided for connection of a voice encryption device SVZ-B.
In the RT-264 sets manufactured after 1.1.1983, all solid state modules were used, these are only partially compatible with the ones in older sets.
The RT-264 frequency-modulated VHF radio was developed by the American Avco Corporation and was launched in the US around 1965.
Only in 1984, when the tank Leopard II was equipped with SE-412/K radios with its electromechanical frequency presets, the RT-264 was installed for the first time in a Swiss Army vehicle.