Daily Archives: August 31, 2016
iPhoneOgraphy – 31 Aug 2016 (Day 244/366)
A walkie-talkie (more formally known as a handheld transceiver, or HT) is a hand-held, portable, two-way radio transceiver. Its development during the Second World War has been variously credited to Donald L. Hings, radio engineer Alfred J. Gross, and engineering teams at Motorola. First used for infantry, similar designs were created for field artillery and tank units, and after the war, walkie-talkies spread to public safety and eventually commercial and jobsite work.
A walkie-talkie is a half-duplex communication device; only one radio on the channel can transmit at a time, although any number can listen. The transceiver is normally in receive mode; when the user wants to talk they press a “push-to-talk” (PTT) button that turns off the receiver and turns on the transmitter. Typical walkie-talkies resemble a telephone handset, possibly slightly larger but still a single unit, with an antenna mounted on the top of the unit. Where a phone’s earpiece is only loud enough to be heard by the user, a walkie-talkie’s built-in speaker can be heard by the user and those in the user’s immediate vicinity. Hand-held transceivers may be used to communicate between each other, or to vehicle-mounted or base stations.
The first radio receiver/transmitter to be widely nicknamed “Walkie-Talkie” was the backpacked Motorola SCR-300, created by an engineering team in 1940 at the Galvin Manufacturing Company (fore-runner of Motorola). The team consisted of Dan Noble, who conceived of the design using frequency modulation; Henryk Magnuski, who was the principal RF engineer; Marion Bond; Lloyd Morris; and Bill Vogel.
Motorola also produced the hand-held AM SCR-536 radio during World War II, and it was called the “Handie-Talkie” (HT). The terms are often confused today, but the original walkie-talkie referred to the back mounted model, while the handie-talkie was the device which could be held entirely in the hand (but had vastly reduced performance). Both devices ran on vacuum tubes and used high voltage dry cell batteries. (Handie-Talkie became a trademark of Motorola, Inc. on May 22, 1951. The application was filed with the U.S. Patent and Trademark Office, and the trademark registration number is 71560123.)
Alfred J. Gross, a radio engineer and one of the developers of the Joan-Eleanor system, also worked on the early technology behind the walkie-talkie between 1934 and 1941, and is sometimes credited with inventing it.
Canadian inventor Donald Hings is also credited with the invention of the walkie-talkie: he created a portable radio signaling system for his employer CM&S in 1937. He called the system a “packset”, but it later became known as the “walkie-talkie”. In 2001, Hings was formally decorated for its significance to the war effort. Hing’s model C-58 “Handy-Talkie” was in military service by 1942, the result of a secret R&D effort that began in 1940.
Following World War II, Raytheon developed the SCR-536’s military replacement, the AN/PRC-6. The AN/PRC-6 circuit used 13 vacuum tubes (receiver and transmitter); a second set of 13 tubes was supplied with the unit as running spares. The unit was factory set with one crystal which could be changed to a different frequency in the field by replacing the crystal and re-tuning the unit. It used a 24 inch whip antenna. There was an optional handset H-33C/PT that could be connected to the AN/PRC-6 by a 5-foot cable. A web sling was provided.
In the mid-1970s the United States Marine Corps initiated an effort to develop a squad radio to replace the unsatisfactory helmet-mounted AN/PRR-9 receiver and receiver/transmitter hand-held AN/PRT-4 (both developed by the US Army). The AN/PRC-68 was first produced in 1976 by Magnavox, was issued to the Marines in the 1980s, and was adopted by the US Army as well.
The abbreviation HT, derived from Motorola’s “Handie Talkie” trademark, is commonly used to refer to portable handheld ham radios, with “walkie-talkie” often used as a layman’s term or specifically to refer to a toy. Public safety or commercial users generally refer to their handhelds simply as “radios”. Surplus Motorola Handie Talkies found their way into the hands of ham radio operators immediately following World War II. Motorola’s public safety radios of the 1950s and 1960s, were loaned or donated to ham groups as part of the Civil Defense program. To avoid trademark infringement, other manufacturers use designations such as “Handheld Transceiver” or “Handie Transceiver” for their products.