A further advance step was made when an audible message was added to the
same radio wave which carried the picture. This is done by modulating
the carrier wave to give audibility, while interrupting the same carrier
wave at a frequency far above the audible range, say, two hundred
thousand cycles, to make our picture.
By means of this duplex employment of the same radio wave, it is
possible to get, for example, both the gesture and the voice of an
inaugural address; the play and the cheers of a national sport; or the
acting and song of grand opera.
Perhaps it might be explained that synchronism in visual-audible radio
reception is accomplished by the simple expedient of keeping the radio
picture “framed,” exactly as this is done in the motion picture theatre.
But continuing the description of the still picture processes a little
further, before taking up Radio Vision and Radio Movies, it might be
added that while photographs by radio is the more interesting and
impressive process, there is little doubt but that radio photo letters
will be of much greater immediate service in business.
Commerce, like an army, can go forward no faster than its means of
communication. The history of industrial advance in all ages shows that
with every addition to communication facilities the volume of business
has increased. Obviously a third electrical means of communication will
enlarge business, and speed up commerce and industry.
As an aid in national defense the chief of staff of the Signal Corps of
the Army, in a recently published report to the Secretary of War, said
(_Washington Star_, November 22, 1924):
“Looking into the future of signal communication for a moment, it
appears that the basic method of breaking messages up into words,
words into letters, letters into dots-and-dashes, and then passing
these through the wrist of an operator, as has been the practice since
Morse’s fundamental invention of the electric telegraph, seems to be
nearing the end of a cycle. Mechanical transmitters with higher speed
qualities are becoming stabilized and American invention seems to be
making further and rapid progress in associating photography with
radio, which bids fair to revolutionize fundamental methods of
transmission.
“The message of the future, whether it be written, printed, of mixed
with diagrams and photographs, including the signature of the sender,
will, it seems certain, soon be transmitted photographically by radio
frequency at a rate tens of times faster than was ever possible by the
dot-and-dash methods of hand transmission.
“Military messages of the future, particularly in active operations,
may contain diagrams and sketches, or even entire sheets of maps, all
transmitted as part of the same message and by means of which
detection or listening-in will be reduced to a very low minimum.”
The author suggests that it might be added that the newcomer, the radio
photogram, has merits distinctly its own, e. g.:
(1) It is autographically authentic; (2) it is photographically
accurate; (3) it is potentially very rapid; (4) it is little effected by
static; (5) it is not effected by storms; and (6) it is automatic and
tireless.
It can also be used to enlarge the individual newspaper’s influence and
prestige by the establishment of photostat branch printing plants at
strategic points, like summer camps, and winter resorts, and at
ridiculously little cost.
Such copies of the news, financial and market report pages of the paper
could be distributed in these distant places before they could possibly
appear on the streets of the home city of the paper.
Of course, produce market reports, stock market news, and similar matter
could be so distributed very much quicker than could be done by any
other system, certainly so to the farmer and gardener.