Evening star., 1932-06-26

~ LAME defects in your radio re-
ceiyers. or else interference con-
ditions beyond the control of the
broadcasters, if reception from
stations within reasonable
distance of your home continues to be
marred by the howls and squeas OF
that old radio bugaboo, Mr.. Heterodyne
For American broadcasting stations Ior
the most part, are now on the straight
and narrow"
Bv this is meant that they are so
operating technically that they should
no longer be webbing" off their as
signed paths in the ether, or wave.
lengths. 1t was last week-Wednes-
day, June %, to be exact-that the
Federal Radio Commissions order
rigidly narrowing permissible devlations
from assigned waves went into effect.
About two-thirds of the country,s
6oO-odd broadcasting stations, lnclud-
ing practically all of major prominence
have complied with the order. Inc
remainder, in most cases stations OF
lesser Importance, face the penal.y oi
extinction unless they have good and
SUFFICIENT reason for their recalcitrance
and have submitted evidence that they
have plans under way to install the re-
uuired frequency monitoring equip
ment.
improvements Noted.
1r,nrovernents in reception conditions
generally have already been noted, ac-
cording to commission engineers. De-
snite the fact that Summer normaiy
Is the season of poorest reception tne
installation of the new precision equip
ment not only has reduced heterooyneS'
but in MANY cases has increased statIon
service areas 25 to 100 per cent. 1llS
winter the favorable effects Will pe
even more perceptlble. ..
THE commissions order, in effect, re-
r,,ired a 600 per cent improvement over
previous practice. Formerly sIatlons
were nermitted to deviate 5OO cycles oi
either side of their assigned %aSe %
lengths. the equivalent Of one klio-
cycle or one dial marking on tne ave- M
age receiving set. the new oluei lio so
1etT,s this permissible deviation 10 oo
cvcles MUS and minus, or maximum
~ one-tenth of a kilocycle. So-calieo
freouencv monitoring equipment, testeo
hy The ITnited States Bureau OF stand
oTds and approved by the Raolo Com,
n,iSsion must be installed IN each anu
e'Tsf Esftvscvcle deviations are inaudiole 10
49, human ear. Heterodynes tnat
so,,nd like hisses are heard wnen tne
dsviations reach 100 cycles. Tney are
iike high-pitched peanut vendors WITS
files at $50 to 500 cycles. AT more tna1
500 cycles they become more snILl anu
penetrating. usually running any pIo-
gram heard. Technically, this Lne
result of carrier wave clashes WIN otllet
transmissions on the same aoJaoeu'
channels, the clashes pelng Kilo"i'
among engineers as beat NOTES.
Aids Closely Listeners.
Fieuratively, the new commission dc
tuno is the equivalent of requiring auto
mobiles to remain within the cnalKeo
| lanes of streets and highways and per-
hitting them to deviate no farther tnan
the outer limit of the chalk markings
According to the commission, the
chief beneficiaries of the new rule are
those listeners living close to station
| hut unable to receive 1t satisfactorily,
| due to interference from other otner
stations on the same channel. Elim-
mating the source of this interference,
| not only is the whistle removed, but the
station itself Is enabled to send out It's
| audible "signals"-its programs-over
wider area.
If heterodyne interference persists,
the engineers declare, 1t can PROBABLY
| be traced to one of two sources, % an
tiuuated receiving sets or sets that need
| servicing and Cd oscillations from cleo
| trical devices such as street cars, igni-
ton systems, elevators, X-rays, refrig-
orators, washing machines, curling irons
and the like. The former can he reme-
died by buying new set or calling in
a competent service man. The latter
| type of interference is barred by ordi-
nance in many communities; 1t is
usually traceable and can be remedied
at the source.