Evening star., 1925-05-31
BROADCAST GAME
V|EWEDBY EXPERT
Carl H. Butman Discusses
Possibilities Relating to
Wave-Length Changes.
BY CARL III. BUTMAN.

Instead of twirling our dials be-
tween the 545.1 and the 200 meter
marks. within a year or two we may
be tuning in stations on 120 or even
100 meters. Many experts and eX-
ponentS of the broadcasting game be-
lieve the future development of
hroadcasting, lies in the use of tsm-
paratively short wave lengths, oper-
ating below the present broadcast
bands. with greatly reduced power.
But there are many experiments yet
to be completed and their results
studied. besides which broadcast re-
Ceiving sets must be modified, to tune
in the lower wave lengths.
In any event the extension of the
band assigned to broadcasting down
ward would make it possible for sta
tionS now awaiting an availab BILE
channel TO open up. 1t would make
room for many more stations on the
air. The lower we go in wave
lengths, the more broadcast chan
nels can be opened: because, as wave
lengths decrease in meters, the sepa-
ration between the channels in kilo-
cycles becomes greater. Between 200
and $50 meters, for example, there
are 500 kilocycles, making possible
80 separate channels, 10 kilocycles
apart, whereas between $50 and 100
meters there are 700 kilocycles, Civ
Ing approximately twice as many
channels.
View as to Class A Stations.
Some radio experts believe that
the present class A stations, particu
larly those on the shorter wave
lengths, will be in better position
for broadcasting in a year or two,
If they hold their assigned channels,
than some of the more powerful
class B stations on the higher wave
lengths. Recent demonstrations with
the shorter wave lengths indicate
their greater practical value and show
that less power is required to pro-
1ect signals to great distances. Be
sides this. the short waves seem to
override static better than the higher
waves.
Not long ago the old amateur band
between 200 and 220 meters was as
signed for use in radio phone broad
casting, where II was badly needed
The amateurs We're very decent. but
lost nothing. as their recent activity
on shorter waves has proven. Many
OF them went down TO around so, 40
and 20 meters, where they now oper-
ate to great distances with less power
ana marked success. The Navy and
other experimental researchers have
also been successful in operating on
wave lengths between 20 and 20 me-
ters, even in daylight. But today
these short channels, or high fire.
QuenCieS, would not be suitable for
oroadcaStlng, as the signals have
tendency to disappear at certain dis
tanceS from their source, unCannily
reappearing again at further away
BroadcaStlng of necessity should
serve in all directions equally well
and at all distances UP to a station S
limiting range. A study of very
short waves is essential before they
can be applied to this phase of radio
telephony, but the study is going
forward.
Field of Probable Extension,
In the band lying just below the
present broadcast band. which is not
now used to any great extent by
amateurs, lies the field where the
probable extension of broadcastfng
rights of way will first be found =.
Manufacturers of broadcast receiv-
ing sets will of course develop and
produce receivers which will reach
to these lower levels. Few such sets
today operate efficiently even at 200
meters, although WIBD at Joliet, Ill.
Is on that wave length. It is of
course now useless to broadcast on
wave lengths below that figure
However, it is no great problem
to design new receivers or modify
the present sets so as to extend the
limits of reception down to even 100
meters. The amateurs have already
improved their receivers, through
their own efforts.
Although today prospective broad
casters are clamoring for long wave
lengths, around 400 meters or above
and also for high power, in the very
near future it will be found that
quite short waves with only mod
crate power will prove more prac-
teal and economical. Therefore. the
class A waves soon will be in great
demand and probably will become as
scarce as the class B channels are
today.