Evening star., 1934-09-30

"Of those stations surveyed, 50 per
cent are deficient in the transmission
of low audio frequencies dow notes
like those of the bull flddle) and Sc
per cent of them are deficient in the
highs. Some of the deficiencies dis
covered in our survey included exces-
sive and eXtraneous noises, limited and
irregular frequency range, poor studio
acoustics and pickup technique. Neg
lecting to correct these conditions will
result in a gradual but steadily in
creasing unfavorable reaction on the
part of those listeners who invest
in the newer receivers"
XJARIOUSLY called the "acorn"
Y or "shoe button" model, a tiny
radio tube designed for use by
experimenters and amateurs working
on the ultra-short wave lengths has
finally been placed in production by
the Radio Corp. of America. The
diminutive tube. which is expected to
stimulate further explorations into
the exceedingly high frequencies look
ing toward harnessing them to every
day use, was first revealed as lab
oratory project about year ago.
So little is known as yet about the
ultra high frequencieS, or micro-waveS,
that the acorn tube, officially called
the 1855" will be watched by the radio
experimenting fraternity closely. 1t
is a heater cathode triode, which may
be used as an amplifier. detector or
oScillator at frequencies up to 600, 900
kilocycleS, or about half meter in
wave length. 1t is said to be the only
triode capable of operating at ultra
high frequencieS.
The tube is essentially designed for
receiving, but it may also be used
for sending over short distances, or
line -of-sight" transmiSsionS. The
ultra short or micro-WaveS usually
shoot forward like beams of light, and
do not penetrate beyond the horizon.
1t is on these wave lengths that fac
simile and television transmission and
reception are expected to find their
ultimate place. The producers of the
new tube emphasize that 1t has been
developed for amateur and expert
mental purposes, and that it cannot
substitute for tubes in the conven-
tional radio sets now in use.
THOSE apparently inescapable huns
l. and buZzes in radio reception,
while not so prevalent as in the
old days, due to improved receiving
sets, are still rampant enough to cause
the radio engineering fraternity and
the radio set manufacturers plenty of
worries. Accordingly, through their
Radio Manufacturers Association,
they are planning to organize a COM
prehenSive campaign to reduce elec-
trical interference with radio recep-
ton by getting at the roots of the
evil.
First of all. the r. M. A. has de-
cided to call an interference confer
ence" of leading radio engineers at
Rochester. N. Y, in November, in con-
nection with the forthcoming annual
meeting there of the Institute of Radio
Engineers. This conference will take
up the man-made interference prob
lens created by power lines, street.
car trolleys, elevators, X-ray machines
and the like 1t will also consider the
work already done on the subject by
the Canadian Department of Marine,
which has undertaken a broad cam
paign against radio interference in
that country.
Most foreign countries levy fines or
penalties upon those held responsible
for persistently disturbing radio pro-
gram reception. In this country the
manufacturers and engineers are pro-
ceeding on the assumption that they
can persuade the operators of elec-
trical disturbing devices to shield or
otherwise correct them to relieve the
undue burden they place on radio. The
problem is especially getting more and
more acute on the short and ultra
short waves, now being increasingly
used for broadcasting and expected
eventually to provide the ether ave-
nues for television.
A.