Evening star., 1952-09-10
Video Signals Flashed
From Iowa to Virginia
Significant Step Reported
By Bureau of Standards
By Thomos R. Henry

Very high frequency signals, within
the television range. now are being
transmitted between Cedar Rapids Iowa,
and Sterling, Va, the National Bureau
of Standards station about 40 miles
west of Washington.
Sometime in the future this may be
extremely significant. TeleviSion at pres
ent usually is restricted to "line of sight"
that is, essentially. from transmits
sion station TO the horizon. The distance
varies little with the terrain. but SO
miles is about the normal limit. Recep-
ton at any greater distance is of the
freak variety.
This is because the extremely short
television waves, unlike the much longer
waves used for radio transmission, go
through the earth's upper atmosphere.
The radio waves are reflected back to
earth from various electrified layers
in the very high atmosphere. the So
called ionosphere.
Puzzled by Bounces.
Now. it appears. something in the
upper atmosphere also reflects tele-
vision waves. National Bureau of Stand
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the waves are bouncing against. One
suggestion is that they may be hitting
whirlpools Of ions, or electrified par
ticles, in the extremely raref1ed roof Of
the atmosphere. Another is that they
bounce from clouds of ions or from
so-called "star dust" The bouncing ap-
pears to be from about the lowest level
Of the ionosphere.
This holds forth 20 promise for long,
distance television in the immediate
future. An extremely minute part Of
the very high frequency beam is re-
flected. Most of it Is lost in space. What
arrives at Sterling is only about 1.O00,-
1000, ,000. .000. .000th of what left the
Iowa station. Signals are sent out with
a power of % kilowatts. About a quad
rillionth of watt gets through to Vir-
ginia. For good picture reception at
the receiving antenna about billionth
OF watt is necessary. This is million
times more than is received at present.
It is doubtful if any intelligence of
any kind could be transmitted in this
way at present, Bureau of Standards
physicists say.
Before there is any likelihood Of prac-
tical use it will be necessary to under
stand the phenomenon, the finding of
which is one of the major developments
in the field Of communications since the
war.
1t has been possible occasionally to get
signals from Cedar Rapids to Bermuda.
This. however. is by no means reliable.
For some years it has been known that
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ticularly in times of magnetic storms, it
has been possible to receive television
signals much beyond the line of sight.
The reason is not entirely clear.
Question of Costs.
Television. Of course, can be trans
mitted as far as one wishes overland by
means Of a succession of retransmitting
stations. There now is q link, for ex-
ample. between the Atlantic and Pacific
Coasts installed by Bell Telephone Co.
Such string Of towers is. Of course,
extremely expensive. Pictures also can
be sent by telegraph and then trans
mitted from televiSion station. Any
wide stretch Of water. however, has been
a seemingly insuperable barrier.
Conceivably the present development
eventually may make direct over-water
transmission possible. There have been
all sorts Of proposals-from q line Of
ships spaced across the Atlantic about
so miles apart, each carrying a re-
transmission station, to line Of circling
airplaneS over the ocean. These might
be practical. If anybody was willing to
pay the price.
Better understanding Of the new phe-
nomenon, however. may make all this
unnecessary.