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[1] Typical walkie-talkies resemble a telephone handset, with a speaker built into one end and a microphone in the other (in some devices the speaker also is used as the microphone) and an antenna mounted on the top of the unit. They are held up to the face to talk. A walkie-talkie is a half-duplex communication device. Multiple walkie-talkies ...
Donald Lewes Hings, CM MBE (November 6, 1907 – February 25, 2004) was a British-Canadian inventor, born in Leicester, England.In 1937 [1] he created a portable radio signaling system for his employer CM&S, which he called a "packset", but which later became known as the "Walkie-Talkie".
Henryk Władysław Magnuski (January 30, 1909 – May 4, 1978) was a Polish telecommunications engineer who worked for Motorola in Chicago.He was a primary contributor in the development of one of the first Walkie-Talkie radios, the Motorola SCR-300, and influenced the company's success in the field of radio communication.
After the war the FCC allocated the first frequencies for personal radio services; the Citizens' Radio Service Frequency Band (1946). Gross formed Gross Electronics Co. [ 5 ] to produce two-way communications system to utilize these frequencies, and his company was the first to receive FCC approval in 1948. [ 2 ]
The range of the unit varied with terrain; from a few hundred feet (about a hundred metres), to approximately one mile (1.5 km) over land, and 3 miles (5 km) over water. [5] Under the Army Nomenclature System, the BC-611 transceiver was the core component of the SCR-536 Signal Corps Radio set. The Signal Corps technical manual number was TM 11-235.
He received a special citation from the Army for this work. Henry Magnuski's contribution towards the development of the SCR-300 "Walkie-Talkie", a 35 pound backpack radio, is documented quite well via two sources, cited below: The Founder's Touch by Harry Mark Petrakis, 1965, McGraw-Hill, NY, p. 144-147 Chapter 13 - The Talkies - Handie and Walkie
GMRS radios are typically handheld portable (walkie-talkies) much like Family Radio Service (FRS) radios, and they share a frequency band with FRS near 462 and 467 MHz. Mobile and base station-style radios are available as well, but these are normally commercial UHF radios as often used in the public service and commercial land mobile bands ...
The lowest series has adjacent tones that are roughly in the harmonic ratio of 2 0.05 to 1 (≈1.035265), while the other two series have adjacent tones roughly in the ratio of 10 0.015 to 1 (≈1.035142). An example technical description can be found in a Philips technical information sheet about their CTCSS products.