Preliminary reports from the field disclose the following information on
the tactical use of wire by the Japanese army. Two samples of Japanese field
wire, mentioned below, used in the northern Burma area, leads to some interesting
findings about the composition and properties of this wire.
The wire is ordinarily used in a single conductor ground return circuit. The
conductors are used only in extreme cases where security is of utmost
The wire is usually laid above ground on bushes or branches, and the same
wire is used for either telephone or telegraph channels.
The supply of field wire in the Japanese army appears to be quite limited. Wire
is very seldom abandoned even at the expense of abandoning other valuable
equipment. Often in new positions the wire may be old or well used.
b. Physical Characteristics
The two samples of field wire were somewhat similar in general appearance
though a marked difference appeared in their physical and electrical
characteristics, Sample No. 1 consisted of three copper and four steel strands twisted
together. The insulation was black rubber approximately 0.030 inches in thickness.
The outer covering was bright yellow, impregnated cotton braid. The outside
diameter of the wire was approximately 0.100 inches and the weight of the
59-foot sample was seven ounces or about 39 pounds per mile. This wire was
somewhat similar to one conductor of the American type W-110 B wire.
Sample No. 2 consisted of seven steel strands and one heavy copper strand
twisted. The insulation was black rubber approximately 0.020 inches in thickness
and the outer covering was a dull red waxed cotton braid. The outside diameter
was approximately the same as that of sample No. 1.
c. Electrical Characteristics
The direct current resistance of sample No. 1 was 1.3 ohms for the 59-foot length
or approximately 22 ohms per 1,000 linear feet. The resistance of the second
sample could not be measured since the length of the section was only 4 feet 10 inches.
Sample No. 1 appeared to be the standard Japanese field wire in use in Burma
and corresponds in characteristics to one conductor of American Type W-110 B field
wire. It was somewhat lighter but had a greater direct current resistance. The
black rubber insulation appeared to be of inferior quality.
Sample No. 2 appeared to be a form of assault wire; however it was much
heavier and much more bulky than the comparable American type. The insulation
of this wire appeared to be very poor. Due to its great tensile strength, this wire
may be intended for use on poles or tied in the air between trees.
Either of these wires, if captured in quantity, could be used with American
field telephone and telegraph sets, either as single conductor, ground return, or two
conductors could be laid in parallel. Used in this way the wire is probably inferior
to American wire in transmission characteristics.