The Amateur Radio Bunble: Hamshack Raspberry Pi for Amateur Radio Activities and The Complete Amateur Radio Contesting Manaul by Dwight Standfield

Author:Dwight Standfield [Standfield, Dwight]
Language: eng
Format: epub
Published: 2018-06-27T23:00:00+00:00

About Propagation

Propagation is one of the most important concepts in ham radios. The term refers to the process of the travel of radio waves through the air as they bounce from safe to surface as they make their way to a radio antenna.

Hams are constantly monitoring the atmosphere for atmospheric conditions such as storms, solar flares and other conditions that may affect the propagation or transmission of radio signals from receiver to antenna simply because the weather can affect the effectiveness of transmissions. This makes having the right equipment (especially an antenna because it’s responsible for receiving radio signals) a requisite. A radio antenna can be complex or simple; it can be a massive tower or it can be something as simple as a wire attached to the circuitry of a radio.

While voice, Morse, and in the modern age, digital operations—most ham stations in existence today combine computers and radio equipment—and ham stations are the most commonly used types of ham radios and communication, from an operational perspective, most hams start out using VHF FM, battery-operated handheld transceivers that receive on one frequency and transmit on another.

To use these FM repeaters, ham enthusiasts have to join local radio clubs that set up and support them by borrowing antenna space from TV station towers (with permission of course) can re-broadcast received signals further thus extending the range.

For this purpose, the FM repeaters receive a signal at a time and immediately rebroadcast it to another frequency that is more powerful than what is available to the hand-held radio. This has the effect of extending the signal range of the hand-held radio. Many developed countries have thousands of FM repeaters and whenever you travel—or any ham radio enthusiast travels—you can find a repeater to use for communication.

Most of the available repeaters use common transmit and receive frequency pairs informally assigned by groups of hams so that any of the frequencies in use does not encroach on the frequency of another repeater and thus cause unwanted interference.

Other than hand-held transceivers and FM repeaters, ham radio enthusiasts also use amateur radio satellites. In this case, ham radio enthusiasts use a satellite overhead to communicate through their hand-held radios. This is very effective because as you may know, natural weather occurrences such as hurricanes or tornadoes tend to disrupt cellphone and telephone communication. In such instances, ham radios come in handy for emergencies. One British satellite repeater has an uplink (receiver) at 145.975 MHZ and a simultaneous downlink (rebroadcast) at 435.070 MHZ.

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