This is my 1965 Unimog S404.114 Radio truck.

Latest additions:




I recently aquired a GRC-106A radio consisting of a RT834 transceiver, MA3349 Power Amplifier, RT662 transceiver and MD522A telex modulator. I removed the original USB filter from the RT834 and replaced it with a LSB/USB filter. A small relay changes the filter that will be used. The GRC-106 is very power hungry... it will require up to 50 Amp. @ 28VDC. To accomodate for this i installed a new power supply rated at 55 amp. nominal output. This PS comes from the Dutch Army and is called a PP6800. To the right of the PS you can see the additional blower that helps cooling the MA3349. You can find more info and pictures on the GRC-106 at Steve Hill's Radiomuseum.

The AN/UGC74B(V3) is an "intelligent terminal", it has several operating modes including emulating a simple send/receive telex at 50 baud.

This charger replaced the old L-193. It is a modern switching power supply rated at 8 Amp. The actual charger module can swivel outwards for easy replacement (why is that important?) ....

This is called "The Redifon Heap". As my first military transceiver ever was a Redifon (GR345B) i always had a weak spot for the brand.The heap consist of several R551N general coverage receivers with the optional synthesizer ERU11B, a few exiters GK203N and the 100Watt amplifier & Power supply GA481C. The amp should actually be a GA481N (for Navy) in wich case it is painted blue. Together these three component form the "643/CJP 100 W HF naval radio station". Al units are now functional, just have to find the time to play with it!

Last year i found a Telefunken E 863 KW/2 HF (1,5 - 30 MHz) receiver that turned out to be a remarkable receiver (what about 8 mechanical filters in the MF!!), it also has the neat digital frequency readout with Nixie tubes and has a PLL lock every 100Hz with +/- 50Hz interpolation. Additional there are 2 TCXO on board. A while later i found the telex modulators that where normally used with the receiver by the German Kriegsmarine (Teletron TG44E). When finally the opportunity came along to buy the transmitter that goes with it, the S2525/3, how could i refuse?? For some reason there are now two S2525/3 transmitters in my small in-house office.... As you can see it doesn't leave me much room! One of the transmitters is interconnected to one of the receivers and is in use as my standard installation, switching between RX/TX is by foot pedal. To make antenna tuning easier i use a Maxxcom tuner at the center of a 2 x 30m dipole, a system that has worked very satisfactory sofar.

Our summer camp 2005, picture 2 shows an empty camping and picture 3 shows why... I tried to make a panoramic picture of the dipole that i erected at the camping site but you will have to use your imagination as well. At the center of the dipole is a SG-230 autotuner that has worked very well, the SG-230 is mounted on a metal cross and hoisted into the 11 meter aluminum mast. The mast is made of collapsable sections and weighs about 13kgs. The last picture is a Wide Band Folded loop (WFL) from RF-Systems that i have put up recently. It has a SWR below 1:2 over the entire HF band but efficiency seems to be a bit low.

A lovely piece of equipment this is: A Russian portable Meteo-kit. All the parts fit into the back of the meter unit including the mast. It gives temperature, barometric pressure, humidity, wind speed and wind direction. It was (or still is?) apearantly used at emergency airfield sites.

Radio camp.

The Unimog in front of some trees, but this time skilfully camouflaged(!) and the new Vehicle Weight-class sign.

In front of the truck: my Matchless G3 (1961). The Guzzi V-50 and finally the all new and revised NDIX32 carburettor, isn't she a beauty!

This strange looking contraption is the "Special VIP Entrance"... It comes in a carrying bag complete with tubing, lines etc. It prevents light escaping from the shelter when the side door is opened.

The luxurious seating arrangement.

Peak through the side door.

I have been busy... I have overhauled the generator, fixed the tilting mechanism that slides the generator out and put it all back in. The generator is now working like a dream and this one runs without any RFI! It can produce 12-24 & 36VDC @ 30A. There is also a fat cable that connects the generator (or other unimogs) to the outlet below the drivers cabin. The last picture shows the inside of the 24VDC to 230VAC static convertor rated @ 1000Watt. New Old Stock "von der Bundeswehr".

For everyday use the smaller generator (0.4KW) is easier to handle.

On the table in the back is a Siemens T100 telex machine that can be connected to the FSE 1300 telex demodulator, the TG440 demodulater or the laptop so i can use it as a printer (not quite the speed of my laserjet at home and the rattle is awesome!). This is the latest version of the RS232 interface, parts of it are build and tested but a few ideas are still experimental. If you are planning to build the interface, please contact me. There is a lot more information on this subject on Christians page:

The TG440 telex demodulator by Teletron. It has an adjustable IF, set to 30kHz to match the IF of the Siemens E311 receiver.

This is a special laptop build to MIL-spec (Itronix XC-6250) with magnesium casing and rubber armoured, waterproof, shockproof, touchscreen etc.) It is resting on it's vehicle mount that is also charging the battery and provides a COM-port for connecting the "Teleprinter-to-RS232-and-back" interface. It can be released quickly from the mount but because of the touch-screen the keyboard is hardly ever used and the position in the mount is fine to work with using the touchscreen stylus. The last pictures show the model with the bigger color/touch screen that i use now, it also has the "Glow in the dark" Nightvue keyboard. The monochrome one is very useful in circumstances where there is bright sunlight hitting the screen. The mono-screen works like a normal digital watch: the more sunlight there is - the better the visibility. I use the laptop for decoding morse, telex etc. or to browse the internet with the PCMCIA GSM-modem attached. There is another vehicle mount in the drivers cabin, the laptop is then used with a GPS and mapping software. The Itronix has proven its worth by now. It can be dropped, run over by a truck, left out in the pouring rain, you name it. (I did not run over mine but someone else did!).

Looking at the front table from left to right there is a Siemens E309 receiver, in the middle a beautiful Siemens E311 receiver, and on the right a Siemens FSE 1300 telex demodulator (IF is 1300kHz) that is connected to the E309 receiver. The other pictures show a few small 100W convertors and other loose bits and the AEG electric heater (below the front desk). The last one is a Kaiser EGW 7,5 "Dynamotor". It is a 350 Watt dynamic converter (24VDC to 230VAC) that produces an absolute Sinewave. It is a 24V motor and a 230V dynamo on the same shaft.

The FSE1300 has been removed to make room for a double set RT-3600, it is a pity but there is just not enough room to leave everything in and the 3600 is a very nice set to work with. On top of the left hand stack is the PRC-2000 transceiver with a 3035 tuner mounted on top of the right hand stack. This is connected to one of the whips of the radio box. The PRC-2000 battery can be charged with the left hand charger at the bottom of the stack (PP3600), the other charger is a PP3610. The 3600 stack can also supply power to the PRC-2000 but it will force the transceiver in "Low Power Mode" (4 Watt).

Link to the Unimog page of Werner Meisterburg with some more pictures of the FSE 1300 in it's original setting.

Link to the pages of Gerd Niephaus with more information on the E311

The original "Zubehörkasten" for the FSE 1300 (click pic to open).

The Hagenuk FuV 100 Power amplifier & Tuner, mounted with its power supply. It looks similar to the well known LV-80 but there are several differences. The FuV 100 power supply can be switched between 12VDC and 24VDC, the selection is visible through a lens in the front panel, the power transistors are covered by a screw-on cap. The amplifier controls are all illuminated and are more like the RA-1 version of this amplifier.

The EM 25 & SEM 25 are now sitting comfortably in the back on top of the generator locker. This is a good spot as the rear chair can swivel between the telex machine and the SEM tranceivers. To the left of the SEM's you can see the Transient filterunit, the SEM cannot handle voltage spikes by itself so this unit should always be installed. The last picture is the SEM 25 spare parts box made of cast aluminium and a real work of art (click pic to open the box).This link will take you to the SEM 25 pages of Mark J. Blair (KE6MYK) with all the info you could ever want to know about this SEM!

Even more Toys for Boys... The right pic is a PRC26 complete with carrying bag, spare antenna and all the other original bits & pieces.

This is the MEL RT-2000 (PRC-2000 as a manpack). The RT-2000 is a HF transceiver from 1.6 to 30 MHz, USB/LSB/CW/DATA, 4 & 20 Watt with integrated fully automatic ATU. It also has DSP functions on USB/LSB to boost peak-to-avarage output power. This one is nr: 7076 and was made in febr. 1992. It has modifications 1 to 5.

The Redifon GR345B. SSB & CW/AM tranceiver, 2-12 MHz and a SEM35 with long & short whip, ready to go!

SEM 52A. The small antenna on the SEM 52A is a special "Field Tunable" Center coil loaded antenna made by Centurion USA. It is tunable from 42MHz to 50MHz by adjusting a small screw in the antenna. There is a spec-sheet in the download area (Ant-Centurion-EXL.pdf). The last picture shows my SEM52 telemike. They seem to be very hard to get so i butchered a spare SEM52 headset. Alas, i forgot to make pictures but inside the headset is a microphone with a seperate amplifier and a small speaker. I used a normal German telemike H33F/PT to be converted. The impedances of both speakers are nearly identical so i only had to move the microphone and amplifier to the new telemike, wich is pretty forward to do. The new telemike is tested and works well.

These small black boxes each hold 4 crystals for the SEM 52A, mine are the number "6" crystals (A to D).

The new "Tire Inflation System" connects to the Brake-air supply. The wooden box holds a rechargeable vehicle lamp with a rare "Wet NiCad" battery, money was no issue with these lamps! I now have all the bits of the lamp complete, even the spare bulbs and a second battery that sits in the bottom of the box. The lamp has a 5W main bulb, a 2W low power bulp and a device that can make the main bulp blink.

This is STM12 mast & antenna head with ATU for the SEM25. The STM12 (SteckMast - 12 meters) was so much fun to erect that i went out and bought the Geroh mast shown below. I still use the STM12 but only when newcomers volunteer to put it up! Next to it is a smaller portable mast of about 7,5 mtr.

Battery charger "L193", has sophisticated RF-filtering and can also be used as a power supply.

24 to 12VDC converter (16A), you can't tell from the picture but inside it is a very modern high efficiency "switching" convertor, built like a tank (or for a tank...).

I installed my spare Unimog heater in the garage, the heater is about 11KW and enough to keep the shed warm in the winter. I also used the petrol pump that comes with the heater.

This Eberspächer BN4 Petrol heater was in my boat for over 20 years and now it serves as a portable Tent-Heater. I made a frame from copper tubing and added a 2L fueltank and a wireless remote control. All it takes is 12VDC for the blower and there you go... (The BN4 is approx. 4200Watt).

The Geroh "Quick Deploy Mast" in place. Link to Geroh

Yep, that's me...


The companies below are my first choice to supply parts for the Unimog or equipment.