Lu.speaker

The Funksprechgerät (fusprech for short) series of vehicle communication devices were for the period arguably considered one of the world’s best compact transceivers ever developed. These eloquently built condensed transceivers were development by Telefunken and manufactured Strassfurt Imperial and Staßfurter Broadcasting GmbH company together producing them in there thousands, equipping many different models of German armoured fighting vehicles including the Sd.Kfz.250, 251 series of halftracks, the heavy (Schwer) 8 Rad armoured cars, self-propelled artillery and of course our light 4 wheeled drive Leichter Panzerspähwagen series of reconnaissance cars from 1940 onwards.

These ‘fusprech’ transceivers were designed to be mounted inside the crew compartment for all AFV’s for short range vehicle to vehicle voice communications. They operated only on a VHF bandwidth since they were only required to cover a relatively short distance. Three versions of this device entered main stream production, starting with the a, d and then f model the later and most common type encountered was produced till the wars end. With each version minor details changed but most notably the bandwidth they covered changed possibly to reflect changes with battlefield tactical needs but also possibly to avoid interference on a battlefield congested with other vehicles using similar communication devices.  

• Fusprech. a: 24.11 - 25.01 Mhz; Produced in 1940-41

 

• Fusprech. d: 23.11 - 24.01 Mhz; Produced in 1941-42

 

• Fusprech. f: 19.99 - 21.47 Mhz; Produced in 1942-45

The b, c and e versions were assigned a bandwidth but for unknown reasons these were never adopted for mainstream use. The required 275 volts power supply was provided from a SEUa or SEUa1 Einankerumformersatz transformer fed from the vehicles own 12v electrical systems. Suitable external speakers such as the LSFu.a were typically used in conjunction with these types of transceivers in many German armoured fighting vehicles including the Leichter Panzerspähwagen series to allow other crew members unable to ‘plug-in’ to the vehicle inter-com system to listen in on radio traffic as would be the case with halftracks too, conversely panzer crews were afforded extra relay boxes to plug into the communications system allowing all crew members to converse albeit at the discretion of the radio operator.

 

Alongside the intricately crafted internal mechanism was a remarkable feature used in these compact transceivers called the RV12P 2000 tube. It was designed as a multi-purpose tube with outstanding performance characteristics being developed around 1935 specifically for the military. The Fusprech contained 6 of the RV 12P 2000 tubes and a single RL 12P 10 power tube. The RL 12P 10 was again also specifically developed for the military and is very similar to the better-known commercial 6V6 type. Although designed for the expectations of military life these valves were inherently fragile so the transceivers were mounted on special sprung dampened trays held within a frame to absorb any impact the vehicle experienced while crossing rough terrain. The antenna could be tuned in both the receive and transmit modes by means of two small knobs and a meter that was used to read RF power output to the antenna. The output power was about 2 to 3 watts and the antenna was between 1.4 and 2 metres in length depending on the model used and being made of an extruded steel tapered pole mounted on a flexible isolated rubber base in a whip like fashion. The Sd.Kfz.223 (fu) as well as having a Fusprech was also equipped with additional long range command network radio equipment initially using the classic Torn.E.b receiver and 30 W.S.a Sender to make up a configuration known as the Fu 10 SE 30 TE set which was connected to a large ‘bed frame’ antenna mounted above the vehicle. These ‘bed frames’ were very conspicuous on the battlefield and often drawn unwanted attention being later replaced with the more slender whip and star antennas being less obvious from afar.  The Set mixes would change as the war progressed for example upgrading to an 80 watt sender in 1943 consequently the Fu XX designation would change accordingly for example becoming the Fu 22 set as in this case. The Kleiner Panzerfunkwagen Sd.Kfz.260 and 261 was also equipped specifically for long range signalling again using different combinations of Receiver and Sender to achieve different tactical requirements. In particular the 260 model featured a Fu 7 SE 20 U set up (Ukw.E.d1 receiver and 20 W.S.d transmitter) alongside the Fusprech for communications with ground to air while the 261 used a Fu 12 set (30W.S.a and Mw.E.c) for communications with Heer ground units.

When considering the thousands of Fusprech units that must have been built during the war to complement each of the vehicles being manufactured and supplied to the front it’s interesting to note that these radio’s seem relatively rare on the collectors market often commanding high prices for mint examples.      

LSFu.a Loud Speaker

fusprech.f & SEUa1 Umformer

Fusprech