SEM 35

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SEM 35
Technical specifications
Frequency range 26.0-69.95 MHz
Frequency deviation +/- 3.5 kHz
Number of channels 880/50 kHz grid
Transmission power 1 W / 150 mW (switchable)
control Grid switch
modulation FM
Bandwidth 15 kHz
sensitivity 0.5 µV with a signal / noise ratio of 20 dB
measurements and weight
height 359 mm
width 270 mm
depth 125 mm
Weight 8.4 kg without batteries
Further data
Manufacturer Standard electrical system Lorenz
Application area armed forces
Factory price € 8057.-

The SEM 35 mobile transmitter / receiver is a two-way radio device that is still used in part by the Bundeswehr alongside the newer SEM 70 and SEM 80/90 devices .

The SEM 35, which is the portable version of the SEM 25 , but only with switchable 1 W or 150 mW, can be used with its more economical power management and the removable battery box as a portable two-way radio or as a relay station and with a vehicle mounting kit (mounting) / base plate. The mobile carrying unit consists of a transmitter-receiver housing including a battery case and weighs 8.4 kg without batteries. In addition to the backpack bag, the supplementary set includes a short and a long antenna with the respective antenna feet and a handset, usually the H-33F / PT from the H-33 series, as is the case with the SEM 25. The base plate for vehicle installation with the dimensions 222 mm × 298 mm × 365 mm weighs another 7.71 kg. When installed, the device is operated via the 24 V truck electrical system and not, as in the case, with 18 V batteries (battery box with twelve mono dry batteries = size D). Commercially available dry batteries with an average capacity of 16 Ah allow the device to be operated for six days in standby mode (approx. 110 mA) with the squelch closed. The consumption with low power is 390 mA or with high power (1 W PEP) 560 mA, which corresponds to a theoretical continuous operation (according to TDv this should be <10% of the standby time) of two or one day. The SEM 35 is vibration-resistant and watertight.

It can be used stationary or in the vehicle with a fixed antenna. As with the SEM 25 , there is an antenna coupler "AGAT" that detects mismatches using capacitance "C" or inductance "L" (adjustable using a 2.5 mm square key , see large clock key size 1 ). The AGAT, connected to the base plate, is set to the set frequency by means of a control cable, the usual antenna base is the MP-65, on which rods with the respective length of 1 m or 50 cm are inserted. For radio operation on the 10-meter and 6-meter bands , 3 × 1-m rods for lambda / 4 and lambda / 2 are suitable. The AGAT should be set to the bands used in 1 MHz steps using an SWR meter. Portable, set up or in a knapsack, there is a flexible antenna base (22 cm long) onto which a flexible leaf antenna can be screwed (75 cm long) or a long plug-in antenna (2.66 m) for more range with a semi-rigid, springy antenna base (22 cm long). These antennas are resonant for the entire frequency range. The range is about 30 km when stationary (plug-in antenna with high performance).

There is an optional DF attachment for the SEM 35. For the training there is the radio interference simulator ECM / FSS 209, which can be switched between the handset and the microphone input of the transceiver or a training system. The LF connection is a U-127-U-specified NATO plug, assigned as follows:

– A = Empfangston (Rx +), geregelt von Lautstärkeeinstellung
– B = Empfangston (Rx −)
– C = Mikrofon (Tx +)
– D = geschaltete 6-V-Stromversorgung für Kohlemikrofon
– E = 6-V-Spannungsausgang für Kohlemikrofon
– F = PTT (TX = auf Masse)
– H = Masse
– J = unbelegt (ausschalten bei 24 V bei SEM 25)
– K = unbelegt
– L = Empfangston, ungeregelt (unabhängig von Lautstärkeeinstellung)

B and H can also be connected together

Handset H-33, wiring diagram

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