Evening star., 1928-10-26
RADIO TUMMY-ACHE.
TESTS ARE PLANNED
Commission Moves Cautious.
Iy About Lack of Broad.
casting Space.

II radios celebrated "tummy-ache''-
lack of sufficient room in the broadcast
bands to be relieved by synchron-
ization of broadcasting stations on one
wave length, the process promises to
be long drawn out and under stringent
regulation.
Synchronization is held to be the
cure for all radio ills, in that it would
offer a way of vastly increasing the
number of simultaneously operating
stations, but proof of this by actual
demonstration remains for the future.
The Federal Radio Commission is
moving cautiously on this phase of the
broadcast problem, seeking way Of
encouraging these experiments and at
the same time minimizing the disturb
ance to existing programs. 1t now is
considering proposed regulations for
Synchronization experiments submitted
by its chief engineer, DR.. j. H. Dellin-
ger, that would require applicants to
submit proof Of their qualifications to
carry on the experiments and conduct
the research in carefully controlled and
checked stages.
Stations would be licensed to operate
spontaneously on full time only after
they had successfully completed four
experimental periods covering not less
than five months.
Nine Possible Methods.
There are nine possible methods of
Synchronization, says DR.. Dellinger,
only one of which has been applied in
practice. A number of stations have
applied for authorization to experiment
with these methods.
Theoretical studies made thus far in
dicate that while heterodyne inter-
ference will be removed by synchron-
ization, there will be in its place an
annoying impairment Of the quality
and fluctuation of intensity due to a
form of interference of the waves of
the two stations, according to DR.. Del
linger. While this may not destroy
as much of the service area as would
heterodyne interference, it will never
theless reduce the service area of each
station.
"The gain to be expected from syn
chronization, If and when it is demon
Strated," he said, therefore is that
many stations may be placed on one
frequency, the sum of their small serv-
ice areas being no greater than the
service area Of one station If operating
alone on the frequency. It is not now
known whether this gain will actually
be realized. In any event, the service
area Of a Synchronized station may be
less than it would have been If it oper-
ated alone on the frequency. There
may be no service in intermediate
areas remote from any Of the syn
chronized stations. The use of only one
station on frequency is likely to con-
tinue as the only means Of giving
service in large rural areas"
Applied to Practice.
The one method Of synchronization
that has been applied in practice, and
that in only one instance, Is of Stations
WBz, Springfield, Mass, and WBZA,
Boston, both of the WESTINGHOUSE Co.
These stations broadcast identical pro-
grams on the same wave length by
sending Of a control frequency by wire
from one station to the other. The
distance between the stations is but 80
miles, and DR.. Dellinger believes that
prohibitive expense probably will pre-
vent general use OF this system over
distances much greater than this.
The goal of these experiments should
De to show the attainment of neces-
sary control Of frequencieS, the nature
and amount of interferences produced
and the net increase or decrease of
program service to the radio audience
In DR.. DellingerS opinion. The expert
mental work which must precede
authorized broadcasting on synchron-
lied basis, he adds, must include DEM
onStration that the emitted waves can
be Synchronized under practical oper-
alton conditions and demonstration
that there is substantial increase of
service to listeners.
tCopyright, 1928, by Consolidated Press)