Evening star., 1922-08-12
SPECIAL RADIO SET
FOR SUBMARINES
Navy Department Engineers
Develop TeIegraphic Trans
mitter and Receiver.
SOON IN GENERAL USE
Improvements Perfected Since the
Initial Installation Aboard the
$50 Was Made.

Radio engineers of the Navy De-
partment have been so successful in
the development of a special radio
telegraphic transmitting and receiv-
ing set for submarines that fifty-nine
new sets have been ordered. They will
be improvements on the experimental
set installed on the $50, which paid
visit to Washington recently, and
was said then to be one of the best
equipped submarines in the world.
The sets will be constructed on con-
fidential specifications drawn up by
the radio section of the bureau of
engineering. based on experimental
sets building at the Washington navy
yard.
approximately 100000 has been
saved on paper-not an actual saving,
because the Navy did not have the
money to save. What the radio eX-
pertS accomplished. however, is Il re-
narkable saving, because practically
new and very excellent long distance
sets Will be available for all the big
subs at very small cost By re-
designing and remodeling old ap-
paratus. barring a few small innova-
perts have built up an entirely new
standard submarine radio set, better
than that on the $50.
Increase In Radius of Action.
The results in radius of action. Rear
Admiral Robson. chief of the bureau
or engineering, says, are twice what
the radio men hoped for when they
began the experiments some months
ago. In other words, instead of u ra-
dfuS Of about loo miles the United
States Navy subs will have a radius
of radio transmission better than two
or three times that distance in ordi-
nary daytime communicate
The first set was Installed on the
R-22 and the resulting experiments
proved that an excellent practical sub
marine set had been evolved by remod-
ehng surplus apparatus and scraps of
present equipment. New apparatus
manufactured by commercial concerns
along the lines Of the perfected Speciti-
cations would have cost, the Navy in
the neighborhood of $500 per set in
stead OF $500. the estimated cost of
remodelng and assembly. Fifty nine
times the difference is S295, ,0U0-saved.
Another remarkable feat accomplish
ed by the Navy was the perfection of
the details of the set within six months.
The original submarine set developed
and built by commercial concern re
Quired two and half years, it is said.
or five times long. When all the
subs are equipped naval experts believe
that these craft of the American Navy
will be just bit better equipped than
those of any other navy in the world.
Few Details Revealed.
Very few details of the new sets are
revealed. but 1t is known that they are
vacuum-tube sets developed along orig
inal American lines. Late i'll the war
German submarines lying on the sur
face succeeded in sending messages
~ ,l,.
miles to their bases by using short wave
lengths of about 800 meters. Spark
sets were used until the last few months
of the war, when vacuum tubes were
introduced in sending. although they
had been used in receiving for about Il
year.
The German spark was operated
on a 500-cycle frequency about 2-k.w.
capacity. Much of their equipment
they considered very confidential and
after an unsuccessful engagement
they threw the important parts over
board or into the bilges. Although
arc-tranSmitting sets are said to be
dangerous for submarine use on ac-
count of the gases given off by the
many electrical storage batteries. >
XIV. arc sets We're used in British
subs successfully. In American sub
marine practice grounded loop is
used. This aerial is very efficient
and consists of highly insulated
the hull. and running to mast amid
ships. Two down leads of the loop
pass through watertight insulators
into the hull, where the primary of
the circuit is connected in series. The
loop is connected with the standard
naval radio equipment by the ordi-
nary means except that condenser
in series is used when transmitting
Long Wave Signals Possible.
Owing to the ability of the under
sea craft to submerge with the aerial
in place, it is possible to receive
longwave signals under water to
depth of about twenty feet, and
short-wave signals to a lesser depth
In 1919, submarine sixteen feet
under water off New York picked
up signals sent out from Arlington,
200 miles away, and while sub
merged at eight feet. heard Nauen
Germany. 1000 miles distant. and
also San Diego
On underwater transmission little
is available for publication. but it is
understood that transmission as well
as reception is practical.