Grapevine radio

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Grapevine radio refers to the transmission infrastructures, used for distributing audio programs, which were built to serve a small number of rural upstate South Carolina communities from the early 1930s to the middle 1940s. Despite their name, these systems did not employ radio transmitters, but were actually a type of "telephone newspaper", because the programs were sent telephonically over wires strung to subscribing homes.

The equipment used to distribute programming over a facility's wire network was located at a central site, for example a general store's back room. Programs normally consisted of retransmissions of radio stations, however, some programming was locally produced, originating from a studio at the distribution site or relayed from a local church or other gathering place. The locally produced programs included announcements and emergency messages, commercials and live performances. The transmissions were made daily, generally starting around 6 a.m. and running until 10:00 p.m. or midnight.

The grapevine systems soon became unneeded, because they primarily served homes that did not have electricity. Once a community received electric service the local grapevine system would soon close down, as the subscribers switched to radio receivers that could receive a wide selection of programs at no cost, instead of the single program and monthly fees characteristic of the grapevine systems.

Information about the grapevine installations (also called "speakerline") is limited, because of their brief history and the fact that they do not appear to have been established outside a small region of South Carolina. Unlike radio stations, they did not require government approval to operate. Their existence was also dependent on an unusual and short-lived economic and technical environment, as they required a central distribution site that had access to electricity, plus a surrounding community of prospective subscribers that did not have electric service.

Throughout the 1930s large parts of the United States, including most farms, did not have electricity. Although organized radio broadcasting had begun in the early 1920s, in rural upstate South Carolina there were no nearby radio stations strong enough to be picked up by battery-less crystal radio receivers, and although battery-powered sets existed, without electrical service there was no convenient way to recharge the batteries. The economic struggles caused by the Great Depression meant that many people could not even afford a newspaper subscription. Thus, there was a lack of entertainment and a strong sense of isolation in the region.[1] As one person remembered, connecting to the grapevine service meant that "we had 'arrived' and were at last in touch with the outside world".[2]

The rural electrification projects of the 1930s and 1940s eventually eliminated potential customers, making the grapevine systems no longer needed as their former customers switched to listening to radio stations.

Initial installation at Mauldin

Wire layout of Gordon Rogers' "grapevine radio" installation as of 1936. The transmissions originated from his home near Mauldin, South Carolina.

The first grapevine system was begun in the winter of 1930-1931 by a high school student, Gordon F. Rogers, who lived on farm in central Greenville county near Mauldin, South Carolina. The Rogers farm, unlike most of its neighbors, had electrical service. Gordon Rogers had shown an early aptitude for engineering, developing a clock that automatically turned on the farm's chicken coop lights at 3:00 a.m., as well as an automated system for watering the chickens.[3] Rogers also had an early interest in radio. Dissatisfied with a battery operated set, he successfully reconditioned a vacuum tube receiver that ran on AC electrical power. At this point he decided to also run a single-wire connection with a ground return from his receiver to a loudspeaker at the home of a neighbor who didn't have electricity. With this setup, whenever Rogers' radio was on the neighbor also heard what was being received. Word of this innovation quickly spread, and within a month lines had been run to seven nearby homes.[4]

Rogers' system was essentially sending one-way telephone signals over his own wires, but he had to use voltages far higher than that used by standard telephone lines, because he was sending not only audio but also the power needed to operate what would become hundreds of loudspeakers. His initial setup output was 2.5 watts, but as the system expanded this was increased in steps over time to 350-400 watts.[5] This occasionally led to issues when his wires ran too close to standard telephone lines, which sometimes picked up the strong grapevine transmissions. Special steps had to be taken to eliminate interference with the telephone company's service.[6]

Subscribers had to provide the wire, poles (often actually fence posts) and speakers needed to connect to the main system lines. Unskilled attempts by individuals to tap into the lines without paying generally caused service disruptions for nearby customers, which made it possible to locate and remove the improper connections. Although at first the service was provided for free, as the number of participants grew Rogers began charging a monthly 10 cent fee.[7] This charge was later raised to 25 cents, and at times a $1 surcharge was applied to finance replacement of sections of the transmission lines that needed to be upgraded from the original iron wire to higher quality materials. The system became profitable enough to finance Rogers' attendance at Clemson College.[3] In 1933, at the time of his college enrollment, the system had 5 miles (8.0 kilometers) of lines and 15 subscribers. Increasing demand, spurred by finding a source of affordable speakers ($2.85 each), expanded the number of connections to more than 200 within the next four months, and by June 1934 the transmission lines spanned 15 miles (24 kilometers). By around 1935, there were 600 homes connected to the grapevine service, including sites in Spartanburg and Laurens counties, located up to 24 miles (39 kilometers) distant from the Rogers farm distribution site. The infrastructure had also grown to 400 miles (640 kilometers) of transmission lines.[8]

Programming was provided for about 12 hours each day. Rogers introduced a "local talent" program that featured live performances. A record player provided music for times when static made it difficult to receive the radio rebroadcasts that provided most of the schedule. Provisions were also made to make local announcements.[9] In addition, a carrier current link from the system based at Ware Place allowed programming originating at that location to be picked up and concurrently transmitted by the Mauldin system.[10]

In the spring of 1936, Rogers, now a junior at Clemson, presented a paper, "Bringing Radio to the Rural Home", at a regional conference of the American Institute of Electrical Engineers, which provided technical information about his innovation. His review won first place in its category.[11] The Mauldin-based system remained in operation until the area received electrical service, shutting down around 1939.[10]

Additional installations

References

Further reading

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