Evening star. [volume] (Washington, D.C.) 1854-1972, 1925-04-05
RADIO GOSSIP AND NEWS

The'radio section of the Department
of Commerce has asked for bids on
dozen new pieces of radio APP
paratus to aid in checking the
emissions of broadcasting stations
and all radio transmitters. This
action is taken with a view OF keep
ing broadcasters and other stations
exactly on their allocated wave
lengths, so as to insure reception on
definite wage lengths, preventing in
reference between radiophone trans
mitterS.
1t is planned to equip the super
visors of radio in the nine national
districts with Piezo electric oscilla-
tors so that all wave-length meas
uring equipment of the, department
may be standardized. The Pfezo
oscillator consists of an ordinary
radio oscillatory circuit in which
there is placed a quartz crystal which
controls the oscillatory periods of the
circuit. in that the quartz crystal will
oscillate only at a definite period. The
special quartz crystal that the de-
partment will use has a fundamental
osciIlatory period of approximately
5000 meters or 100 kcs. AS in other
oscillatory circuits, this circuit also
has harmonics, which appear at null
tiples of the fundamental frequency.
measuring radio emissions of trans
hitting stations can be elaborated
and standardized. BY checking up all
the wave meters used in the field the
department can increase the accuracy
of its portable measuring apparatus
and consequently correct a broadcast
ing station so it transmits exactly on
its assigned wave length or ire
uuency. AS each supervisor meas
in * CT
and because there were variations in
the wave meters used all districts
were not standardized Under the old
practice the wave meters were sent
10 the Bureau of Standards for cali
bration, but due to Earring in ship
ming and use in the field errors and
variations were found. Now each
supervisor can check his meters peri
odically.
Experts of the Bureau of Standards
drew up the specifications for the
Piezo electric oscillator after study
of the principles and some expert
ments with different crystals.
The name Piezo comes from Greek
word denoting pressure. The appa-
ratus operates on this principle: The
spplication of an electric voltage or
pressure on the crystal causes me-
chanical vibrations. When electric
power is applied in the circuit the
result appears in the form of oscilla-
tions indicated by miiliammeter.
When the circuit oscillates it is in
resonance or tuned to the proper fire.
ouency. This makes possible a direct
comparison with the wave meter
under test.
The radio section of the department
did not receive the total estimates
approved by the budget because OF
lack of congressional authority. II
has an increase of only about $4,000,
which will have to be spread over a
large territory. Some new 1nstru-
ments are to be provided for the in
SpectorS working in the field. Each
supervisor should have a short-waVe
receiving set, provided with loop
for listening-in and testing amateur
stations; a special receiver for work
on short-wave broadcasting stations
and a long wave set for testing ship
and commercial stations. They also
need field strength measuring appa-
ratuS to study the ranges and
strength of stations from different
directions and means of transporting
this apparatus from point to point.
This apparatus is needed to keep the
air properly policed so that undue in
reference is not created and the fans,
as we'll as the amateurs and CONNER
cial operators, get a fair deal. Under
the present appropriations, S125,000
less than was asked for, the depart
ment is preparing to keep the air as
clear as possible until Congress meets
in the Fall when Secretary Hoover
will renew his request for necessary
: apparatus and complete field equip
ment for his supervisors and in
Bpectors.