The First Airplane Radio Broadcasting
Major Lester D. Gardner, publisher of Aviation Magazine, at the microphone in Central Park during the two-way airplane-radio broadcasting test. Mr Carl Dreher, right, radio engineer of the Radio Corporation of America and his assistants are shown operating the receiving and amplifying apparatus.
The account of this interesting development as published in the New York Times, gives a clear description of the test. The next use of this method of broadcasting will be in greeting the Prince of Wales when he arrives in New York, and also in greeting the Round the World Fliers when they reach New York City—EDITOR.
Picking the hour of 7 p.m., when radio fans, as a rule, are close to their receiving sets, Station WJZ of the Radio Corporation of America yesterday repeated its experiment of the day before of talking by radio between the earth and an airplane flying over the city and broadcasting the results.
An observer in an airplane from Mitchel Field flying a mile above New York City talked to radio experimenters on the ground and they in turn talked to him, the complete conversation being broadcast to radio fans, who said they heard it perfectly. According the Station WJZ of the Radio Corporation of America, which conducted the tests, this has never been done before, so far as they know, in the history of radio communicaiton. They profess to attach great importance to the results as suggesting enlarged possibilities in broadcasting.
The field station for the test was set up atop a little knoll in Central Park just west of the Mall. Antennae were strung between the trees. The apparatus in the field consisted of a superheterodyne receiver, a remote control amplifier panel and a set of batteries.
Radio signals that came from the airplane were received on the antennae, amplified on the field and sent 3 mi. by wire into the control room of Station WJZ in Aeolian Hall. There they were amplified and modified for quality and sent to the transmitter room, whence they were broadcast with 500-watt power.
The results were noticeably clearer than those of the day before as far as the signals from the plane were concerned. This time the aerial microphone was handled by Maj. William M. Hensley, Commandant of Mitchel Feld. Carl Dreher, the engineer in charge for WJZ, explained that Signal Corps officers had been working all afternoon on the airplane set to eliminate extraneous noises.
Mr. Dreher said the roar that had been heard the day before had not come entirely from the motor in the plane, but that a certain amount of generator hum had been included in it. The Signal Corps engineers, he said, had eliminated a good deal of this by the use of condensers. The same apparatus that had been used the day before was set up in Central Park. Again Maj. Lester D. Gardner, editor of AVIATION, was at the ground microphone. Major Hensley’s DeHaviland 4 plane was piloted by Lieutenant Connell.
The test was pronounced a complete success by the Radio Corporation people. A reporter for The New York Times on the field who listened in with a headpiece for a time could plainly hear the voice of the aviator and his responses to remarks addressed to him from the ground. Outside listeners also reported they had heard the whole conversation perfectly.
One of the handicaps to perfect hearing of what was sent from the airplane came from the roar of the machine’s big Liberty motors. The aviator explained this himself. His microphone was not more than ten or fifteen feet away from his motor, and the roar was transmitted with his voice.
QUESTION AND ANSWER TEST
This time the test was carried on by means of short questions and answers exchanged between Majors Hensley and Gardner. Side remarks by each were caught up by the other in a way that graphically suggested how thoroughly observers screened on the ground could be kept in touch with everything in the four points of the compass that could be seen by a plane a mile up in the air.
It had been agreed beforehand that before answering any question from the ground Major Hensley was to count 1-2-3-4-5-6-7-8-9-10, and that before replying to the voice from the coulds, Major Gardner was to say A-B-C-D-E-F-G. This was to be done in order that each should have opportunity to do fine tuning for the other and to allow time for throwing the switch that changed broadcasting to receiving.
However, so clearly could each hear the other that both Majors often forgot to put in their precautionary signals.
After detailing the apparatus on the field and that in the airplane and explaining how they would work, Major Gardner announced that the moment for the test had arrived.
"If the airplane hears me," he said, "I wish it would now answer."
There was a moment’s pause and then, shot through with the roar of the motor, the voice of the observer in the airplane could be heard.
"We are up here a mile above Central Park—gosh, I’m forgetting that 1-2-3 business," came the voice of Major Hensley at one time.
"Yes, I forget it myself; I get you so clearly," Major Gardner switched in.
It was 7:01 when Major Gardner on the ground began announcing to listeners what was going on. He told of the condition that would be observed and gave a short resume of developments in airplane radio work.
PLANE HIGH OVER MALL
"Where are you?" he asked of the vacant air. In a moment there came an answer.
"Hello, hello, hello, 1-2-3-4-5-6-7-8-9-10, Good evening, Major I get you very well. We are over the Mall in Central Park looking down on one of the greatest panoramas in the world."
"A-B-C-D-E-F-G-. We heard you very clearly indeed," Major Gardner broke in. "Will you tell us what altitude you are at and at what speed you are going through the air." "1-2-3-4-5-6-7-8-9-10. We are about one mile up and—wait a moment—going at approximately 100 mi./hr. Lieut. S. M. Connell—C-o-n-n-e-l-l—is piloting and we are circling with the plane banked to keep as nearly over you as we can."
There followed a series of questions and answers, interrupted by:
"Wait a minute," the voice from the sky said. "I’ve put my foot on one of the wires that leads to the control. Just hold on a second until I reach over and fix it and then we’ll go ahead."
"I can see you up there about 3000 ft. above us," said Major Gardner, introducing his next question.
"Say, Major, you’re a pretty good estimator of airplane heights," interjected the aviator. "You said we were 3000 ft. up and our reading is 3,400 ft. That’s coming pretty close.
"It’s funny to hear a man talking from a mile high above the earth," he said. "Only a few years ago anybody would have said you were crazy if you had predicted it."
Then he launched into a brief history of aviation progress. He alluded to the dawn-to-dusk flight of Lieut. Russell Maughan and to the round-the-world flight.
"Major Hensley, Commandant of Mitchel Field," he said from the sky, "invites you all to be present when the world cruisers arrive there, probably late this month."
At this juncture Major Gardner cut off the sky talker and explained for the benefit of those who might have tuned in after the first announcement what was going on. "The unusual thing about this test is," he added, "that we cannot see the airplane. It may be headed back to Mitchel Field and out of our range. But we will try again. Now I’ll go off, and if the airplane hears me, will it please resume the conversation."
Again the aviator came in.
"We want to thank you," Major Gardner broke in, "for your cooperation in this test through the courtesy of Major Hensley. We have heard everything you said and your talk on aviation was just what the people want to hear. The experiment has been highly successful and will undoubtedly lead to the broadcast reporting of events that could be described as they are happening in no other way."
A few more questions and answers, and then Major Gardner said:
"Well, it’s 29 min. after 7, and President Coolidge will soon be broadcasting, so I guess we’d better stop. Will you say good-bye to the audience from the air?"
"Yes, I’m sorry our time is up," came the response. "I’ve got 7:31. Not wishing to compete with the President. I’ll sign off from the great radio audience. We’re now flying over New York at 4,000 ft. Good-bye."
H. Staples, sexton of the Episcopal Cathedral in Garden City, was waiting on the field when Major Hensley returned. He offered his congratulations.
"I heard every word you spoke," he said, "and I am proud of
having the distinction of being the first to congratulate you personally. That’s why
I drove here." Several hundred automobiles were parked on the flying field by persons
who awaited the return of Major Hensley. All had heard the broadcasting.
Radio set similar to the one used in the experiment.
Note:
The same day the test was conducted an article in the New York Tribune gave
the following radio criticism of the test:
"WJZ stole a march on its contemporaries and supplied us with a thrill. Yes, sir, it supplied us with a thrill. It was about 7:15 when we turned to Major Gardner, the gentleman who has kept us so well informed concerning the progress of the ‘round the world flight. Mr. Gardner was in Central Park using the wire from the Mall that is used for the Goldman concerts. Flying over his head, and well into the clouds, was another major, Major Hensley, of Mitchel Field. If we understood the lower major correctly, the upper major was flying in a DeHaviland. Without a single hitch, we overheard the two men talking to each other. Major Hensley, from a point 4,000 ft. above the Mall, described the scene below him. He was using an airplane transmitter of small power which was being received from at the Mall. Here, no doubt, the speech was heavily amplified and fed in to the land wire that carried it to the modulator tubes at the WJZ studio, where it left to take to the air for a second time. Major Gardner’s voice was broadcast to the radio audience and to the major in the plane by WJZ’s transmitter. It was a highly instructive demonstration and it put a kick in the whole program."
(This article first appeared in Aviation magazine September 8, 1924)
2003 Wings Publishing
