The Washington times., 1914-09-17
PORTABLE WIRELESS
BOON TO GERMANS
Radio Outfits in Field Can Be
Set Up and Used in Fifteen
Minutes.

BERLIN CBy Mail to New York;,
Sept 17.-Portable wireless telegraph
outfits have proved a boon to the Ger
man armies in the field. These outfits
have eliminated the old field telegraph
systems, which were so tedious to lay
and which, when strung through hos
tile country, were so easily cut and put
out Of commission. Only along perma-
nently esta ablished lines of Communica-
ton are the lines laid for telegraphic
and telephone purposes.
In other countries the armies have
not solved the problem of portable wire
less equipments. They are still cum
brous and far from easily handled: they
also DO not always give the service
needed, and are easily put out of COM
mission. The short range equipment
carried by the German field forces can
be transported by motorCyclist c00
miles a day. Long range equipment can
be carried thirty miles in twenty-four
hours by man and horse. The short
range instruments will send and re-
ceive over an average of thirty five
miles, where the country is not hilly.
Larger sizes will carry a distance Of
$50 miles unless the topography of the
country inteTferes.
L
The instruments can be set up and
ready for transmission of messages
Sithin fifteen minutes of their arrival
ct any point. They can be taken down
and made ready for transportation in
from eight to ten minutes.
To return TO the matter of transport
ing the equipment il might be added
that in country where neither horse nor
motor propelled vehicle can travel. 1t is
carried by men on specially constructed
bamboo .'stretchers.'
The regular wireless crew consists
of seven men and two officers. Two
look after the horses. five are employ
ed in setting up the equipment or dis
manteling il, and the two officers send
and receive messages.
The mast is of aluminium alloy and
is built in eight sections each six feet
long, provided with slip joints. The
mast first is joined together on the
ground, the guy ropes are attached. and
the whole raised. The lower point is
formed of a socket bedded in bitumen.
which in turn is encased in metal tube
provided with a pointed shoe.
If the ground is too rocky TO permit
of easy insertion. those members of
the crew who are not generating cleo
tricity or sending, hold the mast in
position by means of the guy ropes.
The aerial is very ingeniously devised.
II consists OF A number of bronze wire
conductors radiatine out like the ribs of
an inverted umbrella. These are accu-
rately balanced and counterpoised. and
the radiatinc wires are attached to in
sulators fastened near the bottom of
the mast
Small Dynamo Available
For sending purposes dry batteries OF
a special make are supposed TO be used.
but in case these are not available a
small dynamo. coupled to a pedaling
a-rangement, forms part of the outfit.
With this man can easily drive the
generator at a speed OF 1900 to 400
revolutions per minute. and so provide
a current of one ampere at fifty volts.
which is amply sufficient for sending
purposes.
hTe weight of dynamo and pedal drive
is ninety-nine pounds and II is so ar
ranged that it can be carried by one
man by means of straps, which fasten
across the shoulders.
The transmitter and receiver. the lat
ter of which is OF the well-known
''head-dress' pattern, are designed SO
as to be as light as possible, and it
might be considered that a certain
amount Of efficiency has been sacrificed
10 obtain increased portability and ease
in erecting.
II is Interesting 10 note that the wave
length is about 36i meters, with a coup
ling OF per cent unvarisble, and the
equipment can exclude waves of per
cent variation.
The sending can be carried out with
great rapidly, and the transmitting and
receiving apparatus, without the mast
and aerial, weighs only eighty-ive
pounds.