Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-10-06
COLUMBIA PLANS
CHANNEL TESTS
Experiments With Synchroni-
cation to Prove or Disprove
Operation Theory.

In an endeavor to help solve radios
congestion problem, the Columbia
Broadcasting System has undertaken
extensive experiments with synchroni-
zation to prove or disprove the theory
that more than one high-powered
broadcaSting station can operate at the
same time on the same channel.
The experiments are being conducted
by two Of Columbia'S leading stations.
WABC. It's key" station at New York,
and WCAU, at Philadelphia. Although
these stations are separated by less than
100 miles, they were selected because
experiments conducted over so short Q
distance would be Of the most rigid
order, and II successful would prove
beyond doubt the feasibility Of multiple
operation Of stations on one channel
without ruinouS heterodyne interfer-
ence.
PIckard Suggests Tests.
At the suggestion of Sam Pickard,
vice president of Columbia and former
Federal radio commissioner, the tests
have been undertaken. AS. member
of the commission Mr.. Pickard always
chung to the theory that radios greatest
difficulty-lack OF room III the ether
could be overcome when a successful
means of synchroniZation Is found. En-
gineerS perSistently have held that two
stations Of power beyond 1000 watts,
regardless Of tlse distance between them,
cannot operate at the same time with
out destroying each others programs
over a large area that otherwise might
be served. They say this Is feasible
when the signals are controlled by
parallel wire lines, but the expense OF
maintaining such lines is prohibitive
over large areas.
Mr.. Pickard says that synchronization
has never been undertaken ON COM
prehensive basis.
I'VE are giving it whirl for all It's
worth. with the very best equipment"
he said. Thus far We have been en-
gagged In making extensive prepara-
tons, and it likely will be some time
before we can talk actual results
Columbia Experiments.
The tests are being conducted volun-
| tarily by the Columbia. Recently the
Federal Radio Commission granted the
two Columbia stations permission to
carry on the tests. The authorization
was for the stations to conduct them on
| the -Eilocycle channel, assigned to
station WABC OH a cleared-channel ba-
sis between the hours OF am. and 5
| a m, when there would be no interior
ence with regular broadcaSting. The
New York station operates with 5000
watts and WCAU with 1000. Both prob
ably will use / 900 during the tests.
Mr.. Pickard called at the commission
to discuss with engineers the procedure
to be followed In the experiments. He
also sought an extension of time dur
ing which they may be conducted. since
the present authorization expired Oc-
tober /. There will be no objection tc
| the continuation.
The idea behind the tests. said Mr.
Pickard, is to learn whether chain
programs may be transmitted by two OIL
more stations on a single channel with
out marring the quality of reception
This could be accomplished II the sta
tions adhere absolutely to their as.
signed frequency. Once either trans
mitter deviates, heterodyne whistle
sets up Immediately, and the greater the
"wobble" the more ruinous the hetero-
dyne.
Set Up Telephone Lines.
| Western Electric engineers are super.
yiSinP the tests and the installation Of