Evening star., 1925-04-24
SHORT WAVES OPEN
NEW RADIO FIELD
Macmillan Polar Party to
Garry LoW-PoWer Sender
of Long Range.

The discovery of the possibilities ot
the new 20 and 40 meter wave bands
and the tremendous distances that car
be covered by comparatively low pow
ers on these short waves has opened
up a new field for experimental de
velopnnent. The 20-meter band is es
pecially interesting. as 1t has appar
emily conquered the diminution of the
range of transmitters in the daytime
as compared with their normal night
time distance. In designing and build
ing the equipment to be supplied DR.
Donald B. Macmillan on his next
Arctic expedition sailing in June. the
engineers of the Zenith Radio Labora
tory of Chicago, in cooperation with
the well known short-waVe radio eX
pert. John L. Reinartz, have been
forced to consider the daylight condi
tions under which communication
must be maintained between the Mac
MILAN expedition and civilization. due
to the fact that DR.. Macmillan will be
in "a hours of daylight during almost
his entire stay in the north.
Small Power Required.
In addition TO the equipment sup
piled the Macmillan ship for com
munication with the United States
the two Navy amphibian aeroplanes
which viii accompany the expedition
are also being equipped with very
loW-poWered Short-waVe equipment for
communication with the mother ship
These transmitters of necessity are
very light and small. being entirely
dry-cell operated. The transmitter
tube used is the ordinary UV-201A,
such as is used as a detector tube in
an ordinary broadcast receiver. This
will give an idea of the extremely
small power available
During the past week the Mac
MILAN ship equipment. as we'll as the
aeroplane equipment. has been given
its initial tests with some astounding
results. On the night of April 20
Engineer Reinartz, testing one of the
small aeroplane transmitters a his
home at South Manchester. Conn
carried on communication with anna
teur radio station SCIC. owned by
John Benedict at Kalama ZOO. Mich. a
distance Of approximately 500 miles
using wave length of 80 meters
This establishes a remarkable new
world record for low-power short-wave
transmission.
Only Dry Cells Used.
This work was accomplished with
the regular equipment which will be
supplied the aeroplane the only power
supply uStU DelIlS 0TS cells ana tne
transmitter tube being an ordinary
receiving set detector tube. The total
power available was, therefore. ap-
proXimately 140 of that used in an
ordinary electric light bulb.
The Macmillan ship transmitter also
had its share in breaking world
records On the morning of Sunday,
April 10, in a test carried on from the
Zenith Radio Laboratories, in Chicago.
this outfit, operating on wave lengths
OF 20 and 40 meters. was heard very
loudly by Lieut.. f. II. Schnell. radio
officer of the l.. s. S. Seattle, flagship
of the United States Navy Pacific fleet
now engaged in war-game maneuvers
en- route TO Hawaii AT the time Lieut..
Schnell heard these signals he reports
the distance of the Seattle from San
Francisco as 500 miles. This test
was carried on in daylight and the
total distance covered was approx
imately 4 1000 miles-an astounding
range for a lower power transmitter.
Further tests will be conducted with
both the aeroplane and the ship set
before DR.. Macmillan sails for the
North. 1t is possible that even these
records may themselves be broken in
further tests with this apparatus.