Evening star., 1925-10-04
WIRELESS BEACON
BOON TO Av|AT0RS
Light Signals Enable Flyers
to Detect Slight Variations
From True Course.
! BY CARL H. BUTMAN.

A special type Of radio receiver,
which permits air pilots to maintain
a course through darkness and fog
toward a radio beacon is the latest
development in radio and aeronautics.
This improved radio receiver or indi-
Gator is visual, in that the pilot does
not have to listen in continually for
he code signals which keep him on
his route; he merely watches three
Tiny electric lights on his dashboard.
They are operated by the radio signals
picked up when his receiver is prop
erly tuned on the beacon, and indi-
Gates to him whether he is on his
proper course or veering to the right
or left.
Radio beacon finding, or directional
flying, tests have been conducted for
some time at McCook Field, in Day
ton, the pilots using the radio beacon
1T Wilbur Wright Field, which sends
out a series OF guiding signals for
their use. The development of this
system, patterned somewhat after
The marine methods. has been through
: the cooperation of the Signal Corps
and Air Service experts at McCook
Field and the Air Mail Service. In
the tests, pilots frequently flew from
the field and lost themselves in the
air, trusting to the radio beacon to
guide them home. In this they were
always successful within q; radius Of
about 200 miles.
New System Used.
The original system was called the
equi-Signal system, in which two sig
nails transmitted simultaneously from
the beacon had to be kept at equal
strength to assure the pilot that he
was on the proper line or flying to-
ward the beacon. a development
made during the past year is an inn
provement. 1t is known as the inter-
locking signal system. Two distinct
signals are still sent out but they
combine to form a third character
when the airplane is on the right
line. If the aviator goes to the left
Of the course he hears only one sig
nal, the Morse letter a.. transmitted
& in code. When he is off the
course TO the right he hears the
Morse letter IN or t--.) in code
If flying exactly on the prescribed
course, these two-letter signals COM
bine to form a continuous repetition
uf the code letter IT., or a series of
dashes. Hearing the series of dashes
continually. he Is sure his route is
toward the beacon, but when this
series break up. he is either to the
right or left and must change his
continuous signals
Visual Indicator Used.
The difficulty found with this
method in flying toward a beacon was
the constant attention required by the
pilot. who has several other things to
do when flying his plane. Dependence
upon his ears required. too great con-
centration, increasing the chance of
nd
make it easier for the pilots, the
visual indicator was devised.
Three small electric lights mounted
on the instrument board in front of
the flyer, when properly connected
with his special receiver. flash and
80 out depending upon his course The
unbroken series of 1T" signals. or
dashes, which is picked UP by the set
when two signals are received with
equal intensity. operates d relay
which causes a. white light to flash
This is the proper course light, the
constant flashing of which shows the
pilot that he is flying toward his
beacon. When the plane is off the
route to the left a, RED light flashes;
when on the right, the green lamp
flashes. The port and starboard sig
nails used at sea are followed in fly-
Ing.
a new radio beacon of this type Is
now being erected at Monmouth. ILL.,,
under the supervision of the McCook
Field radio experts When completed
this beacon will be a valuable guide
10 the Air Mail pilots. and to Army
AirWay flyers making night trips or in
bad or foSgy weather, provided their
planes are equipped with the neces-
Sary apparatus for following the bea-
cons guiding signals.