147. General

Two types of remote control detonating devices were employed by the Germans in World War II. The most recently used equipment consisted of mines laid in a mine field and connected with electrical wiring to a remote control post where a concealed observer could electrically detonate all or part of the mine field (par. 149). The earlier type of re-mote control mine detonating was by radio (par. 148). The Germans used electrical deto-nating devices in conjunction with their detector equipment for detecting foot-troop or vehicular approach and underground activity (sec. III, ch. 9).

148. Radio Detonating Device B1 (Fernzündgerät B1; F.Z. B1)

a. General. The radio detonating device B1 is designed to fire electric detonators by ra-dio. This device usually employed large charges of explosives hidden in buildings, debris, bridge abutments, and the like, and usually not in mine fields. The radio detonating devi-ce B1 is patterned after the Soviet F-10 radio controlled fuze described in detail in TM 5-223A. Each set of equipment consists of two transmitters and five receivers. Each trans-mitter and receiver is cable of being turned to any one of five different frequencies. The 15-watt transmitter with battery and transformer, which is designed to be used with a rod aerial and counterpoise ground, serves to originate and send the signal. The receiver, operated by wet cell batteries, is served by a ground antenna and counterpoise. The five interchangeable sets of relays for the receivers and the spare parts for both transmitter and receivers are contained in a small pack.

b. Transmitter. The crystal-modulated special transmitter with modulating adjustment is housed in a normal carrying pack, which is a reinforced wooden case with a removable lid. The transmitter fits in an upper compartement, with the converter below. In a special compartment are 11 aerial rods, an aerial base, a transverse head, a counterpoise in 4 parts, a cable for connecting the battery to the transmitter, a square key for winding the clock-work firing switch and for switching on the required signal, and a safety key. The 12-volt wet cell battery (12 NC 28) is in a sheet-metal box. Spare parts for the transmitter, including electron tubes, bulb, 40-ampere fuzes, and high-and low-tension brushes, are carried in a small case with a removable lid. The transmitter should be erec-ted clear of trees, walls, or metallic objects.

c. Receiver. The receiver, which is set to the frequency of the transmitter, is a crystal-modulated heterodyne receiver serced by a ground antenna laid out toward the transmit-ter. The voltage required for ignition is excited in a pair of terminals. The resultant igni-tion is indicated by the momentary glowing of a red lamp in the receiver. By means of in-terchangeable relay sets, the receiver may be set to react to any one of five different signals. The receiver is carried in a container divided into two compartements. The recei-ver itself is housed in one compartement and the power supply in the other. Each com-partment can be separatly closed by a waterproof cover. The terminals for the aerial, the counterpoise, and the ignition leads, together with two carrying handles, are all on the outside of the container. One section of the power supply compartment contains the aerial and the counterpoise, and the remainder holds three batteries (2.4 NC 58) in a re-movable container and one direct-current vibratory converter. Spare relays, electron tu-bes, bulbs, and vibrator units for the receiver are conained in a small case with a remo-vable lid.