Hobby radio

Chapter Hobby radio

Teach Yourself Electricity and Electronics Third Edition Book
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Teach Yourself Electricity and Electronics Third Edition Book

  • car. If a potential thief knows your vehicle has a wireless security system, he or shewill probably not want to spend a lot of time snooping around to find and disable the system.If someone manages to steal your car and it has a wireless security system in-stalled, and if you’re lucky enough to find out about the theft within a short time, tellthe police about the security system. The police have a wireless transmitter thatsends out a signal that contains the vehicle identification number (VIN) for your car.This signal is received by the equipment in your car, which starts up its own trans-mitter. Using radiolocation equipment, the police can pinpoint the position of yourcar on a map. From there, mobile direction-finding radio receivers can be used toreach the car. In some cases the police have caught thieves while they were actuallydriving stolen cars.A home or business wireless security system operates like a paging device orbeeper. If something happens that triggers the security system, a radio signal is trans-mitted that sets off a small radio receiver you carry. Such a system will ideally telephonethe police and/or fire department as well. If you happen to be reasonably near yourhome or business, you can drive to the site.Hobby radioIn most countries of the world, people can obtain government-issued licenses tosend and receive messages via radio for nonprofessional purposes. In America, thishobby is called amateur radio or ham radio. If you want only to listen to commu-nications and broadcasting, and not to transmit signals, you do not need a license inthe United States (although you might need one in certain other countries).Who uses amateur radio?Anyone can use ham radio. Amateur radio operators, often called radio hams, can com-municate using any of numerous modes, including speech, Morse code, television, andradioteletype (RTTY). This last mode, RTTY, can be done in real time, or by postingmessages in a manner similar to the way computer users exchange information by electronic mail (e-mail). Radio hams have set up their own radio networks. Some ofthese networks have Internet gateways. This is known as packet radio.Some radio hams chat about anything they can think of (except business matters,which are illegal to discuss via ham radio). Others like to practice emergency-commu-nications skills, so they can be of public service during crises such as hurricanes, earth-quakes, or floods. Still others like to go out into the wilderness and talk to peoplethousands of miles away while sitting out under the stars. Amateur radio operatorscommunicate from cars, boats, aircraft, and bicycles; this is called mobile operation.When transceivers are used while walking or hiking, it is known as portable or hand-held operation.Amateur equipment and licensingA simple ham radio station has a transceiver (transmitter/receiver), a microphone,and an antenna. A small station can fit on a desktop and is about the size of a homeHobby radio617