Operating mode (amateur radio)

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The term operating modes is understood in the amateur radio service after telephony ( radiotelephone ) and telegraphy ( Morse code telegraphy ) also computer-aided, mostly digital, methods for the transmission of data (mostly text) via radio . However, images and files can also be transferred at a relatively high speed.

While SSTV , AMTOR , PACTOR , PSK , RTTY and others rely on a suitable device or computer (also referred to as MGM - machine generated mode -), Morse code (CW - Continuous Wave ) can also be operated by hand. If a computer is used to decode the signals, the received LF signal is fed into the sound card . The signals to be sent are converted accordingly by the sound card and then sent. A Terminal Node Controller (TNC) such as a modem can also be used instead of the sound card .

The digital processes ( "digimodes" ) have expanded amateur radio. With these, sometimes extremely fast (such as HSCW - High Speed ​​Continuous Wave ) methods, data can be transmitted over normal radio channels in a matter of seconds.

The signal-to-noise ratio (SNR) is decisive for the reception . While telephony signals (voice radio) require a minimum bandwidth of approx. 3 kHz and a signal-to-noise ratio of approx. 30  dB in order to be understandable, other operating modes can still be decoded if the SNR is very low. So it happens that with Morse Code and some digital modes such as PSK31 and FT8 with lower transmission power, greater ranges can be achieved than with radiotelephone.

Send types

The types of transmission can also be distinguished from one another with regard to their types of modulation .

AMTOR (Amateur Teleprinting Over Radio)
Transmission of telex signals
ATV (Amateur Television, Radio Television )
Transmission of television signals
Transmission of data using an error-correcting code
C4FM ( Continuous 4-Level Frequency Modulation)
digital voice and data radio
DATV (Digital Amateur Television)
Transmission of digital television signals
D-STAR (Digital Smart Technologies for Amateur Radio)
digital radio
Digital mobile radio
digital voice and data radio
FAX (facsimile)
Transmission of compressed image signals (from a FAX machine) via AM or FM
Eightfold frequency shift keying for the digital transmission of texts
G-TOR (Golay-Teleprinting Over Radio)
Transmission of data using an error-correcting code and data compression up to 300 baud
Packet radio
Transmission of digital messages in a computerized communication system
APRS ( Automatic Packet Reporting System )
Transmission of position beacons, weather data, text messages
PACTOR (Packet Teleprinting Over Radio)
Transmission of telex signals
Telephony ( radiotelephone )
The transmission of speech. Used modulation types are single-sideband (SSB) with a bandwidth up to 3 kHz and about 30 MHz and frequency modulation (FM) up to 20 kHz bandwidth. Amplitude modulation and narrowband FM are rare
Telegraphy (CW, Morse Code )
The transmission of Morse code
RTTY (radio teletype, radio telex )
asynchronous serial transmission of digital data, usually Baudot code (CCITT-2) or ASCII in the frequency shift keying method
SATV (narrow band ATV)
Transmission of television signals with a bandwidth of up to 2 MHz without audio and color subcarriers
SSTV ( Slow Scan Television )
Continuous image transmission with a bandwidth below 3 kHz over a normal SSB or FM connection. Originally with a refresh rate of 8 s with an image resolution of 120 lines, expanded in various ways to enable higher resolutions and color transmission
WSJT (Weak Signal Communication, by K1JT)
Group of transmission protocols for a low signal-to-noise ratio.

See also

Web links

Commons : audio signals of various modes  - collection of images, videos and audio files