Monday, April 24, 2017
The First Wireless Experiments in Indiana
It was in April 1899, that Professor Jerome Green at the University of Notre Dame at South Bend, in the north of the state of Indiana, made his first experiments in wireless transmission. Working with several interested students, Professor Green assembled the necessary equipment for a spark transmitter and a coherer receiver as a locally made copy of the equipment assembled by Guglielmo Marconi in Italy and England.
In his first experiments, Professor Green hung a wire ten feet long from the ceiling in the Physics Laboratory in Science Hall (now La Fortune Hall) as the antenna, and another wire connected to a nearby steam pipe as the earthing system. The transmitter was a battery powered spark coil that could produce sparks nearly a foot long.
In an adjoining room, a suspended wire six feet long formed the antenna and the earthing wire was again connected to a nearby steam pipe. The receiver was a coherer, that is a very small glass tube with an internal diameter of just 1/8th inch, filled with silver and nickel filings. Successful wireless transmissions were achieved with the sending and receiving apparatuses in the adjoining rooms.
Next they set up their apparatus in two separate buildings 100 feet apart, with similarly successful results. Then they ventured further apart, with the receiver in another building, Sorin Hall, 500 feet distant. On each occasion, the transmitter remained in the Science Building, and the receiver was installed in buildings progressively further apart.
However, we should mention that on each occasion, the earth connection from the transmitter and the earth connection from the receiver were always attached to nearby steam pipes. It would seem to us that on each occasion the transmission was achieved successfully through both pathways simultaneously; through the air from the transmitting antenna to the receiving antenna and also through the connections to the steam pipe system.
However, in a subsequent experiment, they attached the transmitting antenna wire to a flagpole 125 feet high and reception was achieved at a distance of two miles. The receiver was then moved to another location another mile further distant with suburban South Bend in between. Strong signals were again received in this experiment over an air distance of three miles.
Their next experiment was from Notre Dame University to a location in Mishawaka, an air distance of six miles. However, that distance was just too much for their primitive apparatus, and this time no signal was received. That failed experiment was the end of the wireless experiments at the Notre Dame University in April of the year 1899.
However, due to their successful experimentation in South Bend, Professor Green was invited to conduct similar experiments during the month of May (1899) in the downtown area of the city of Chicago in nearby Illinois. Initially the transmitter was setup at the Polk Street Railway Station and the receiver in the Tribune (newspaper) Building, a distance of ¾ mile. Due to excessive electrical interference from many intervening wire systems, this experiment was not successful.
In a subsequent experiment, the transmitter was installed in the new skyscraper Monadnock Building and the receiver again in the Tribune Building, a clear distance of less than half a mile with no intervening wire systems. The received signal on this occasion, according to a news item in the Tribune newspaper, was described as strong. Similar experiments also occurred in another new skyscraper, the Marquette Building.
Later the transmitter was set up at the Life Saving Station at the mouth of the Chicago River and the receiver on a tugboat out on the lake. That final experiment was indeed successful with the reception also of a very strong signal.
In all of those wireless experiments, Professor Green acknowledged that he invented nothing, that all he did was to copy the work of the famous Guglielmo Marconi, and he demonstrated that yes, the Marconi system did work. Transmissions over water, he affirmed, were stronger than over the land. However, his pioneering work at Notre Dame University is accorded the honor of being the first wireless experimentation in the state of Indiana.
at 5:00 AM