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A walkie talkie (more formally referred to as a hand-held transceiver or HT) is a hand-held portable two-way transceiver. Its development during the Second World War was praised by Donald L. hings, radio engineer Alfred J. gross and Motorola's engineering team. Originally used for infantry, walkie talkies were designed for field artillery and tank units. After the war, walkie talkies were widely spread to the public security field, and finally used for business and field work.
A typical walkie talkie is similar to a telephone handset, with a speaker on one end and a microphone on the other (in some devices, the speaker is also used as a microphone), while the antenna is mounted on the top of the device. They dare not speak. Walkie talkie is a half duplex communication device. Multiple walkie talkies use one radio channel, which can only transmit one radio at a time, although it can be listened to at a time. The transceiver is usually in receive mode. When users want to speak, they have to press the PTT button to turn off the receiver and turn on the transmitter.
Canadian inventor Donald hings first created a portable radio signal system for his employer CM & s in 1937. He called the system a "packet," although it was later called a "walkie talkie.". In 2001, hings was officially decorated for its importance to the war. Hings' C-58 "handy talkie" began military service in 1942, which is the result of secret research and development work started in 1940.
Alfred J. gross, a radio engineer and one of the developers of Joan Eleanor's system, also worked on the early technology behind the walkie talkie between 1938 and 1941, sometimes believed to have invented it.
The second device widely known as "walkie talkie" was the backpack Motorola scr-300 developed by the US military during the Second World War. It was created in 1940 by the engineering team of Galvin manufacturing company, the predecessor of Motorola. The team consisted of Dan noble, who conceived the design using FM technology. Lead RF engineers Henry K magnuski; Marion bond Lloyd Morris; and bill Vogel.
The first walkie talkie was an am scr-536 transceiver produced in 1941, which was also produced by Motorola. It was called handie talkie (HT). These terms are often confusing today, but the original walkie talkie refers to the model installed on the back, and the walkie talkie is a device that can be completely held in hand. Both devices use vacuum tubes and are powered by high-voltage dry cells.
After World War II, Raytheon developed an / prc-6, a military alternative to scr-536. The an / prc-6 circuit uses 13 vacuum tubes (receivers and transmitters); a second set of 13 tubes is supplied with the unit as an operational spare part. The device is factory set with a crystal, which can be changed to other frequencies on site by changing the crystal and readjusting the device. It uses a 24 inch whip antenna. There is an optional handset that can be connected to an / prc-6 via a 5-foot cable. Adjustable belts are provided for handling and support during operation.
In the mid-1970s, the U.S. Marine Corps began to develop a team radio to replace unsatisfactory helmeted an / prr-9 receivers and receiver / transmitter handheld an / prt-4 (both developed by the U.S. Army). An / prc-68 was first produced by MAGNAVOX in 1976, released to the Marine Corps in the 1980s, and adopted by the U.S. Army.
The abbreviation HT, derived from Motorola's "handie talkie" trademark, is usually used to refer to portable portable ham radio, and "walkie talkie" is usually used as layman's term or specifically refers to toys. Public security and commercial users often refer to their handheld devices as "radios.". After World War II, the redundant Motorola handie talkies soon entered the hands of amateur radio operators. As part of the civil defense program, Motorola's public safety broadcasts in the 1950s and 1960s were loaned or donated to ham. In order to avoid trademark infringement, other manufacturers use names such as "handled transformer" or "handled transformer" on their products.
Walkie talkies are widely used in any environment that requires portable radio communication, including commercial, public security, military, outdoor entertainment, etc., and can be purchased from low-cost toy simulation devices to solid and durable equipment at different prices. For example, analog and digital units (such as waterproof or intrinsically safe) used in ships or heavy industries. Most countries allow the sale of walkie talkies, at least for commercial, maritime communications and some limited personal purposes, such as CB broadcasting and amateur radio design. Due to the increasing use of small electronic devices, walkie talkies can be made very small, and some personal two-way two-way UHF radio models are smaller than a deck of cards (although they may be much larger due to the need for larger VHF and HF units) antennas and batteries). In addition, with the cost reduction, it is possible to add advanced squelch functions to cheap radio equipment, such as CTCSS (analog squelch) and DCS (Digital squelch) (usually sold as "privacy code"), as well as voice scrambling and relay functions. Some devices (especially amateur HT) also include a DTMF keypad for remote operation of various devices (such as repeaters). Some models include the vox feature for hands-free operation, as well as the ability to connect external microphones and speakers.
Household and commercial devices differ in many ways. Commercial equipment is usually robust, with a metal case, and usually only a few specific frequencies are programmed (usually, though not always, with a computer or other external programming device; older equipment can simply exchange crystals), as a given business or public security agent must always adhere to a specific frequency distribution. Consumer devices, on the other hand, are often manufactured to be small and light, and to be able to access any channel within a specified frequency band, rather than just a subset of the allocated channels.
