Development of Panzer throat mikes

[Nick Komiya]

Capsule markings

[Richard P]

Nick,

I hope this thread is going to continue. It's the first I have leaned about any panzer radio gear. Thanks for starting this.

Richard

[Michael H. Pruett]

Excellent Thread

Thank you Nick, very well done.

Regards,
Mike

[Zauberflöte]

[QUOTE=Nick Komiya;3408490]

These Kmf.2 units were all recalled during 1937/38 and had their microphone capsule attachments upgraded to the type with the capsule housing, and some were also fitted with a new relay box. Newly manufactured throat mikes from 1938 combined the new capsule housing system with the new switch box to become the Kmf.a and Kmf. b, throat mikes that remained the standard until the end of the war, The difference between the “a” and “b” designations is that the former had a 2-prong plug and the latter a 3-prong with corresponding circuit differences within the switch box.

Nick, can you tell me the difference in use for the 2-prong plug compared to the 3-prong plug? Was the 2-prong for different communication devices/ different armour?

Thank you
F

[Nick Komiya]

If you read the manual for the Tiger I, the Tigerfibel, it explains how to use the switch on the mikes in combination with the switches on the intercom box operated by the radio man to alter the combination of people who can speak or listen in to the conversation. The number of prongs varied to optimize these communication patterns (combination of participants in a conversation). And who used which throat mike ( a or b) depended on which intercom box was installed in the vehicle, which further depended on the stage of the war and the vehicle. So it was a combination of when, who and which vechicle that determined the allocation of mike types.
Tanks installed with the early intercom boxes "Z", "10b" and "11 (for command tanks)" only used kmf.a, the 2-pronged mikes, but those that employed the intercom box 20 like the Tiger I had the commander and radio man wearing the 3-prongs and the gunner and driver the 2-prongs. Then selfpropelled artillery and assault guns using intercom boxes 23, 23a and 24 only employed the 3-pronged kmf.b for everyone, as those vehicles had loud speakers installed unlike tanks, which again changed the range of participants.

[Nick Komiya]

Update

When I originally started this thread I wasn’t able to illustrate all the variations, so I thought I should provide an update here to complete the overview of Panzer throat mike and headset variants.
Kmf.a and Kmf.b throat microphones.
Shown below are throat mikes Kmf.a and Kmf.b next to each other. The Kmf. a with the simple 2-prong plug only had a “on-off” switching function, while the 3-pronged Kmf.b allowed more complex switchboard-like operations in connection with the use of the radio transmitter and receiver. Early tanks employed the Kmf.a for all crew, but after the introduction of an intercom amplifier in 1941/42, the commander and radio operator, who both required more complex switching options to access external radio traffic, got the Kmf.b whereas the rest of the crew stayed with the simpler Kmf.a.

[Nick Komiya]

Comparison of the plugs

[Nick Komiya]

Metal tag identifying the Kmf.a

[Nick Komiya]

Panzerkasten 20
As headset and throat mike spec evolution was largely just a knock-on effect of changes at the heart of the system, it becomes easier to understand those changes to the business end by looking at what was going on at the core, namely the intercom box. The new intercom amplifier box 20 introduced in 1941/42 became a standard component for tanks throughout the war ( Stugs, however, used different models ). This box was located beside the radio between the driver and the radioman, so the two would hook up their headsets and throat mikes to this box. Before this box was introduced, the intercom system in tanks was not equipped with an amplifier. Instead, the tank’s “UKW.E.e” radio receiver had been modified since March 1940 to lend part of its circuitry to provide the amplification. At the same time, “10 W.S.c” Radio transmitters were also modified to help power the throat mikes and these modified radios were identified by a vertical yellow line on the upper part of the front panel.
The intercom box 20, gave the radioman’s Kmf.b access to the radio transmitter as default, meaning without him having to press the microphone switch. Thus in constant connection with external radio traffic, the radioman played the role of switchboard operator of his tank, and by pressing his mike switch when there was an incoming call for the commander, he gave the commander access to the transmitter. However, this action could cut the commander off, in mid sentence, from his dialog with the gunner and driver on the intercom channel and disrupt internal communication. As a remedy, the circuit in the box was rewired in 1943/44, to let the commander himself initiate the switch over to external communications by pressing his microphone switch. In this case, the radioman would notify the commander on the intercom that there was an incoming call, and the commander could then switch over to radio when it suited him. Those box 20 units that had this modification done were so marked with a red bar on the side of the box, as the example in the photo.

[Nick Komiya]

The famous Tigerfibel and Panther-Fibel dedicate several pages to how to use the Kmf.b microphones in association with the Panzerkasten 20. Here the pages from the Tigerfibel.

[Nick Komiya]

Dfh.b and Dfh.d Headsets
As in the case of the throat mikes, not everyone in the same tank wore the same headset. In pre-42 Panzer III/IVs, before the introduction of the intercom box 20, only the radioman wore the headset Dfh.b, which is the type most readily available for collectors today. Everyone else actually wore headsets with the designation “Dfh.d”, which were connected to intercom connection points, i.e. socket box units Z19 or Z20. Dfh.d headsets are easily identified by their small plugs with short stubby prongs. Externally, other than the plug and markings, they were identical to the Dfh.b, but internally they were totally different in their makeup. Because these headsets needed to serve a system that had no amplification, the resistance value is only 54 ohm whereas the Dfh.b is 2000 ohm. They are rare today, because they became obsolete in tanks when the Intercom box 20 arrived which gave the whole system a power boost that required all headsets to be upgraded to 2000 ohm, and also switched all the socket boxes to accommodate the Dfh.b plugs. The Dfh.ds did see further use, however, in the armored cars used by the Ordnungpolizei. The one in the photo is a 1942 marked example, which was already starting to be phased out at the time of manufacture.

[Nick Komiya]

Comparing the plugs, the most notable difference

[Nick Komiya]

Comparing the external markings

[Nick Komiya]

The Dfh.d capsule on right shows the marking of 54 ohm, 42

[Nick Komiya]

The inside shows by markings on top that the Dfh.b has 2x1000 ohm, while the Dfh.d has 2x27 ohm composition