Evening star., 1926-05-11

Ramm, who must take pictures and
keep the log.
Capt Amundsen, Mr.. Ellsworth,
Lieut.. RiiserLarsen and Col. Mobile
must be pretty much on the job all
the time, particularly in bad weather
All, of course, have nothing warm to
eat, only the condensed diet which
Amundsen has found valuable on
polar expeditions; but sleep and food
are two of the least Of their worries.
Wireless Set Simple.
The wireless set TO he used on the
dirigible Norge during her fight across
the Pole is an extremely simple send;
ing and receiving machine made by
the Marconi Co. specially for use on a
trip during which all parts must be
easily accessible, interchangeable and
carefully insulated. II is estimated by
Capt. Birger Gottwaldt, the wireless
expert of the ship, that 1t will have a
range OF 900 to 1000 miles, SO that
the ship should be In touch at all times
with the civilized world.
1t will also be equipped with direc-
ton finder similar to those used by
ships at sea, so that the position Of
the airship may be checked by wire
less signals from the large stations of
Europe and America. BY obtaining
cross bearings the position of the ship
may be closely placed.
The generator for the transmission
apparatus Is a high-tension machine
rated at 500 watts and $500 volts at
1000 revolutions a minute.
The transmission set is a special
Marconi direct coupled circuit with
anode feed. The transmission circuit
consists of two transmitting valves,
al hat
watts with an ordinary direct coupled
circuit to the aerial, there being no
intermediate circuit.
The energy in the aerial is a maxi.
mum of 200 watts. and the wave
length 500 to 1900 meters. The aerial
Is 800 feet long, dropping through an
insulator on the floor of the cabin
with sinker on the end.
Expect to Speak Ships at Sea.
For transmission. either continuous
waves will be used, or they may be
chopped up with an interrupter so
that messages may be received from
the airship by ships at sea. There
are two tubes in parallel, taking in
about 400 watts each.
The set Is rather open and especial
ly insulated for use in varying tenn
peratures. 1t had to be built so that
man working with half-frozen fin
gers mig hit easily get at its parts and
change them.
The aerial tuning conductance con-
sists of wide-spaced turns of bare
copper wire of unusually heavy gauge
and insulated on porcelain. The coil
has tappings for the valves, the aerial
and also the reaction coil inside for
the grid circuit. The key used is
an ordinary sending key, with a mo-
tor interrupter to break up the sig
mails.
The receiver consists of a special
tuner with open and closed circuits
and a coil-holder for three sets of
coils specially made for this machine.
The tuner is an open and closed cir
cult. very simply made and works
from 800 to $4,000 meters merely by
changing the coils, putting in larger
coils for longer waves.
There is a Seven-tube amplifier of
the Marconi type, and a telephone
amplifier may be added as well as a
doubie-note magnifier. Between the
amplifier and the high and low fire.
ouency amplifier a note-filter may be
introduced the most efficient note fire.
quency being from 500 to 1000 cycles.
A special single tube heterodyne
will also be carried. covering the same