A replacement radio vehicle (Ersatz-Funkwagen) or a replacement motor vehicle (Ersatz-Kraftfahrzeug) was a replacement vehicle assigned to the troop for missing special vehicles.
Many people always think that the Wehrmacht was very well equipped with vehicles in the early war years. However, this is only true to a very limited extent, since the majority of the Wehrmacht actually moved ahead with horses during the Polish and French campaigns.
Although more and more vehicles were made available to the Wehrmacht, far more vehicles were needed for the rapid operations.
As it had always been a "tradition" in the German military, they knew how to help each other.

The Citroen U23 used by the german Wehrmacht


So-called replacement vehicles were simply made available for missing vehicles. These were either civilian vehicles or captured vehicles which were then converted by the soldiers themselves into almost fully-fledged special vehicles.
It should be noted that it is really interesting how many foreign car brands can be found on original photographs of the Wehrmacht. Renault, Citroen, Rover, DAF, Dodge, Ford,... The list of foreign vehicles used is very long.

The motor vehicles could either be taken over 1:1, or they had to be provisionally prepared for special tasks.

The project "Wehrmacht Ersatz-Funkkraftwagen (Replacement-radio-truck) - How a Citroen U23 becomes an Wehrmacht Kfz.61" is about exactly such a replacement vehicle.
Here a light Citroen U23 truck was assigned to the unit of my grandfather. This had to be prepared then makeshift from a commercial motor vehicle to a so-called replacement radio motor vehicle.
The leaflet D963/8 "Merkblatt für die behelfsmäßige Herrichtung von handelsüblichen Kraftwagen als Ersatz-Funkwagen" gives exact information about what had to be paid attention to.

Merkblatt für die behelfsmäßige Herrichtung von handelsüblichen Kraftwagen als Ersatz-Funkwagen


According to these instructions, only the following radio vehicles were permitted to be used as replacement radio vehicles:

  • Funkkraftwagen Kfz.61
  • Funkkraftwagen Kfz.17
  • Funkkraftwagen Kfz.17/1
  • Funkkraftwagen Kfz.2

Actually there are no exact building regulations! For all soldiers, the leaflet was regarded as a "comprehensive overview of tried and tested patterns as an indication of possible remedies".
So instead of building regulations, the Wehrmacht had guidelines on how to set up and equip replacement radio vehicles!
"It is left to the skill of the troops to carry out the fitting-out work on the basis of these guidelines, but experience has shown that a general regulation is highly recommended at least in the association of an AK (army corps). The intelligence departments (Nachrichtenabteilungen) are to be consulted for cooperation with the troop intelligence units (Truppennachrichtenverbänden)."
The difference between the Nachrichtenabteilungen and the Truppennachrichtenverbänden is shown in this article (at the moment only available in german):

Aufteilung der Truppennachrichtendienste in der Wehrmacht


In summary, there are no rules, only guidelines. A free hand for the soldiers but under the supervision of the intelligence departments. Within an army corps, however, the replacement radio vehicles should have a similar structure.
This is surprisingly open for a military instruction and explains why no defined instruction but only a leaflet was issued.

Now, however, there are different radio teams in signal units which were each transported with differently equipped radio cars.
Most of the communication units were so-called motorized units.
To be part of a motor unit (mot.-Einheit) by definition, a vehicle had to be available to transport the soldier. Many may also know the term "fast troops", which results from this.
By the allocation of the replacement vehicles exactly this principle was ensured as far as possible.
And exactly about this there are now more exact guidelines in the leaflet:

  1. The scope and type of the telecommunications equipment form the basis for a technically usable facility.
  2. It must be possible to transport the crew to which the "Funktrupp" is entitled according to the number of crew members.
  3. The weight of the complete equipment and crew must not exceed the load capacity of the vehicle.
  4. As a rule, the required power sources of the radio equipment shall be provided by making use of the power source system of the motor vehicle. Only if the replacement position does not permit the allocation of such devices to motor vehicles shall other vehicle types be used, but in accordance with the principles described under 1) and 3), because in this case a battery with sufficient storage capacity corresponding to the radio set shall be additionally provided. The provision of the collectors required for this purpose shall be specially arranged. It must also not be overlooked that such a power source supply of the makeshift radio teams requires a regulated supply of collectors for use.


The following (very interesting) table contains a compilation of the "Funktrupps" with the radio vehicles to be replaced, the weight data for the telecommunications loading and crew, as well as power requirement data for the radios:

List of the Wehrmacht Funktrupps


For the project "Wehrmacht Ersatz-Funkkraftwagen (Replacement-radio-truck) - How a Citroen U23 becomes an Wehrmacht Kfz.61" the consecutive number 2 is important:
The radio crew (mot.) is the m.Fu.Tr.b (medium radio crew b).
The radio, i.e. the transmitter, is a 100-watt transmitter (100-Watt Sender).
The Kfz.15 and Kfz.17 are registered as vehicles to be replaced. But it is a Kfz.61. More about this further down in the text.
The weight of the telecommunications load is approx. 495 kg.
For the weight of the crew (including full equipment) 800 kg were estimated, thus 100 kg per soldier.
The power consumption at 12V is 40 - 45 Ampere.


The Funkkraftwagen Kfz.61

But how do I come up with a Kfz.61 for the project?

Wehrmacht Kfz.61


As already stated in the project description, the size of the replacement radio car, the equipment to be seen on the pictures and also the information from the photo album indicates this. In fact you can see my grandfather on many of the pictures in a Kfz.61. At least until 1941. So the assumption is obvious that the Kfz.61 was destroyed or heavily damaged and the unit of my grandfather was equipped with the replacement radio car Citroen U23, or was assigned a Citroen U23 and carried out the box construction himself.

The Kfz.61 is actually dealt with in a separate part of the leaflet. The equipment of a Kfz.61 includes so much that this would simply be too much for this leaflet. Therefore, it does not appear in the above list, but has a separate part in the leaflet.

Structure of the devices in a german Kfz.61Structure of the devices in a german Kfz.61


The radio motor vehicle Kfz.61 was registered within the Wehrmacht as a "light radio motor vehicle (Funkkraftwagen)". The "Heavy Funkkraftwagen" was e.g. the Kfz.72.
Within the D963/8 the Kfz.61 is actually similarly led as the Kfz.17. At least if it concerns the example for a spare radio car.
The only difference: The Kfz.61 served primarily as an example for the makeshift installation of trucks with a closed body of more than 1 t payload.
Kfz.17 served as an example for trucks with open and closed bodies of more than 1 t payload.
The data sheet for Kfz.17/1 goes even further. This serves as an example for trucks with less than 1 t payload or more than 1 t payload.

Wehrmacht Kfz.61 storage
The replacement radio car Citroen U23 had to fully replace the Kfz.61.
This also included the storage space for the equipment of the radio crew.


A replacement radio car for the Kfz.61 had to be set up according to the D963/8 for sending in motion. This means that the radio operation in the provisionally prepared vehicle had to function while the vehicle was in motion.
The basis for this, of course, is a permanently installed roof antenna, which can be easily recognised from the Citroen U23.

Roof antenna of the Citroen U23


The height of the roof antenna naturally had a great influence on the transmission power. Therefore there were precise instructions:

  • It had to be at least 30cm above the roof.
  • It must not be above 2.95m above the ground.

The 2.95m are calculated from the fact that it was essential for the Wehrmacht that the vehicles could be transported by rail. The vehicles were therefore allowed to have a maximum of 2.95m high and a maximum of 3m wide.

Dimensions of the german Opel Blitz radio car


By the way: If it was not otherwise possible and the antenna went beyond the maximum dimension, the antenna had to be provided as a removable antenna.

An important question which is still in the room is whether the box structure of the Citroen U23 was made of sheet metal. Sheet metal was not actually used for radio cars. The bodies were usually made of wood or cardboard which had the reason that a sheet metal body has a negative influence on the antenna performance.

In the D963/8 it says to this:
"Also the use of trucks with closed sheet metal construction must remain limited only to urgent exceptional cases, if not at least the roof is made of wood. (e.g. Opel truck with closed body on 3 t chassis)".

In all factual terms: It is rather unlikely that the box construction of the Citroen U23 is a pure sheet metal construction, but still not impossible.

These are first of all all generally summarized information about the replacement radio cars in relation to the Citroen U23.
In the following parts I will deal in more detail with the antenna construction and the installation in replacement radio cars - especially with the installation of the Citroen U23 replacement radio car.

The next part will deal specifically with the "set of installation equipment for the preparation of commercial trucks with a payload of 1t and more" (Satz Einbaugerät für die Herrichtung handelsüblicher Lastkraftwagen von 1t Nutzlast und mehr)

So it remains exciting!

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