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Antennen (Antennas)

The SEM system has a number of antennas. The portable SEM 35 is used as a man pack with either a short tape antenna, or a longer sectional whip. If the SEM 35 is mounted on it's own mounting, it uses the same antenna configurations as the SEM 25 system.
As the original SEM 35 antenna's were in short supply in surplus, several traders developed a trick to be able to offer antenna's: they took the AT-272A/PRC antenna - tape antenna and it's flexible mount - and fitted this with a bolt fitting the SEM 35 antenna connector. It works. But it is not original.

The vehicular SEM 25 can be used with a Antenne-Fahrzeugbetrieb SEM 25 (Vehicular Antenna).
The SEM 25 also can be used with the Antenne-Standbetrieb SEM 25/35 (Fixed Antenna).
The receiver only EM 25 has no separate antenna in the schematics found until now - it hooks up to an extra connector on the Antennen-Abstimgerät (Antenna Tuner) that is part of all SEM 25 antenna configurations.

In all configurations except for the man pack SEM 35 they share the same antenna tuner, that must be adjusted for every MHz. using the Antenna Tuner Test Set. The tuner is controlled by the transceiver through a special control cable, adjusting itself for each frequency used.

Antenne-Fahrzeugbetrieb SEM 25 (Vehicular Antenna) Vers.-Nr. 5820-12-139-5229

This consist of the well known combination of Mast Sections MS-116, MS-117 and MS-118, combined with a standard MP-50 or MP-65 Mast Base.
The system uses the vehicle as counterpoise.
This antenna is hooked up to the radio through the Antennen-Abstimgerät (Antenna Tuner).
I suppose there should be a carrying bag for the Mast Sections and actually have seen a number of candidates - but up to now the official documentation has not yielded any positive identification.

Antenne-Standbetrieb SEM 25/35 (Fixed Antenna) Vers.-Nr. 5820-12-149-2543

A complete system, using it's own counterpoise. Cables measure 10 meters, so the antenna can be elevated.
The system comes in three cotton duck bags, holding the cables, the mast sections and the antenna base combined with the antenna tuner respectively.
The antenna tuner is mounted within a protecting housing, keeping out direct rain.
The complete set-up has three long radials, each consisting of two MS-116, one MS-117 and one MS-118. The vertical then would comprise of one MS-116, one MS-117 and one MS-118.

Antenne Fuß / Abstimmgerät Tragetasche (Antenna Base / Tuner Carrying Bag) Vers.-Nr. 5820-12-150-0308

Cotton duck, webbing carrying handle, draw cord closure

Antenne Staben Tragetasche (Mast Sections Carrying Bag) Vers.-Nr. 5820-12-150-0309

Cotton duck (internally rubberised?), webbing carrying handle, tightening strap halfway, flap closure. Main compartment contains 7 each MS-116-A and 4 each MS-117-A, front compartment contains 4 each MS-118-A-K Mast Sections.

Antenne Stab MS-116-A (Mast Section) Vers.-Nr. 5985-00-199-8831

Manufacturers: Telefunken; Telemit; Century Metal; J & H Smith MFG CO; Unknown (Marked D0094, 887)

Antenne Stab MS-117-A (Mast Section) Vers.-Nr. 5820-00-199-8843

Also found with Vers.-Nr. 5985-00-115-7149
Unmarked one sectional tapered
Manufacturers: Telemit; Standard Elektrik Lorenz AG; Unmarked

Antenne Stab MS-118-A-K (Mast Section) Vers.-Nr. 5985-12-140-3988

Also sometimes labelled as MS-118AK.
4 each
All sectional tapered
Manufacturers: Telemit; Unknown (Marked D1901)

Antenne Kabel Tragetasche (Antenna Cables Carrying Bag) Vers.-Nr. 5820-12-150-0310

Cotton duck, webbing carrying handle, closed with two aluminium buckles.
It holds three cables measuring 10 meters each: ground, signal and tuner control. Of these signal and tuner control are clipped together with small metal and rubber clips - these seem to be prone to loosing and can be found replaced by duct tape.
Some 70 centimetres from the female connector 10 of the cable assembly there is a heavy clamp, holding both cables together with a 30 centimetre lanyard attached to it, ending in a heavy karabiner hook. This is meant to be clicked on the antenna assembly as a strain relief. Some 10 centimetres beyond this clamp there is a second one, that seems to be meant to loop the cables back unto themselves in order to stop water running down.

Massenkabel (Ground cable) Vers.-Nr. 5995-12-156-9122

Two clamps on each side, to insure ground connection. A wing nut is provided on the antenna assembly, connection on the side of the transceiver unknown yet. Cable stamped: C.1142 5995-416100.
Diameter 16 millimetres; length 10 meter

HF Signal Kabel (Antenna Signal Cable) Vers.-Nr. 5995-12-150-1016

Also labelled SEL 56. Connector 14 on both sides.
Diameter XX millimetres; length 10 meter

Antennen-Abstimgerät Kontrolle Kabel (Antenna Tuner Control Cable) Vers.-Nr. 5995-12-150-1017

Also labelled SEL 3
Female connector number 10. Also clamps and lanyard on this side.
Male connector number 10.
Diameter XX millimetres; length 10 meter

Halte Seil (Lanyard) Vers.-Nr. 5820-12-150-8941

Marked on small metal disc. Meant as strain relief, clipped to antenna assembly.

Antennen-Abstimgerät (Antenna Tuner) Vers.-Nr. 5820-12-141-1252

EM 25 has no tuning control - it is always combined with a tuner connected to a transceiver that has a tuning control.

Originally the tuner is mounted on it's own Schwingmetallrahmen (shock mount) - mostly missing in surplus. Nomenclature and further data of this shock mount unknown. No electronics inside this shock mount.

External controls and connectors
Connector 10: Control to SEM 25 or  SEM 35 Grundplatte (Mounting)
Connector 14: Antenna signal to SEM 25 or SEM 35 Grundplatte (Mounting)
Connector 15: Antenna signal to EM 25 Grundplatte (Mounting)
Clamp ANT.: Antenna base, carries antenna signal in.
Nut: Ground
Covered Tuning Control MHz L: Opened when adjusting tuner for specific vehicle
Covered Tuning Control MHz C: Opened when adjusting tuner for specific vehicle
Technical data
Height: 110 mm; Width: 290 mm; Depth: 122 mm; Weight: 3,89 Kg

Last updated: 17-06-2005 10:20 +0200
Copyright © 2001, 2002, 2003, 2004, 2005 A.J.M.O. Witkop. All Rights Reserved.