A walkie-talkie, hand-held and portable, is a two-way radio transceiver. Its development has been credited to Donald L. Hings, Alfred J. Gross, and engineering teams at Motorola. Other armed forces were developing similar designs. Walkie-talkies were commonly used in public safety, commercial and industrial job sites after the war.
The walkie-talkies include a half-duplex channel as well as a “push-to-talk” switch that starts transmission. The typical version is similar to a telephone handset, maybe larger, with an antenna attached to the top. The walkie-talkie’s speaker can be heard by those in the vicinity unlike in a phone which can only be heard by one user.
The backpacked Motorola SCR-300 created at the Galvin Manufacturing Company was the first radio receiver to be nicknamed “Walkie-Talkie”. Motorola’s hand-held AM SCR-536 was named the “Handie-Talkie”. Both of these ran on vacuum tubes and were powered on high voltage dry cell batteries.
Alfred J. Gross did a lot of the early research behind the walkie-talkie between 1931 and 1941 and is sometimes credited with its invention. His portable high-frequency radio with two-way communications feature was noticed by the U.S. Office of Strategic Services and they recruited him to make the two-way air-to-ground radio system that was later converted for use by troops behind enemy lines. Canadian inventor Donald Hings was also credited with the walkie-talkie invention when he created a portable radio signaling system in 1937.
After World War II the military developed replacement. This new unit is factory set with one crystal and may changed to a different frequency in the field by replacing the crystal and re-tuning the unit.
The Marine Corps, in 1970s, started working on a replacement for their unsatisfactory helmet-mounted AN/PRR-9 receiver. The AN/PRC-68 was the result and along with the Marines the US army adopted it.
HT, the abbreviation for “Handie Talkie”, is used in conjuction with handheld ham radios while the term “walkie talkie” is used to refer to a toy. Public safety and commercial users often refer to their handheld devices simply as “radios”. In the modern arena some cellular telephone networks offer a push-to-talk device that allows walkie-talkie like operations without dialing a call. Walkie-talkies are commonly used where portable radio communications are necessary, including business, public safety, military, and outdoor recreation. Most countries allow the sale of walkie-talkies. Due to the increasing use of miniaturized electronics walkie-talkies can be made very small. Generally commercial equipment is ruggedized, with metal cases, and often have only a few frequencies programmed into it since many business must often abide by a specific frequency allocation. Consumer gear is usually lightweight and capable of accessing any channel within a specific band. Along with consumer and commercial users the military in most countries continue to use handheld radios for various purposes.
In the amateur handheld arena Digital Smart Technology, or D-STAR, is a new addition. Handheld radios with this technology include narrower bandwidth, simultaneous voice and messaging, GPS position reporting, and call sign routed radio calls over a wide ranging international network. Commercial walkie-talkies can be reprogrammed to operate on amateur frequencies and many amateur radio operators do this believing that commercial gear is built more solidly than amateur gear.
Personal walkie-talkies make a good communication tool due to their ability to be mass manufactured for cheap. Many times these unlicensed transceivers can interfere with users of licensed services. Canada reallocated frequencies for unlicensed use because US GMRS users were causing heavy interference.
Most personal walkie-talkies operate in the UHF allocations, are compact, have buttons to change channels, and a short fixed antenna. They are often made of heavy, brightly colored plastics. Sometimes two-way radios are combined with GPS receivers or are equipped to send text messages and pictures between similar equipment.
Jobsite and government radios are most often rated in power output while consumer radios are frequently and controversially rated in mile ratings. Often these claims are believed to be outlandish due to UHF signals. Most walkie-talkie traffic is in the 27 MHz area and in the 400-500 MHz area of the UHF spectrum.