![]() The RSID (automatic mode detection and tuning) feature uses a special sequence of tones transmitted at the beginning of each transmission to identify and tune in the signals received. Some modes require more care than others, and of course you need to have the software set for the correct mode first - not always so easy! ![]() Using a point and click technique with the mouse, you can click on the center of a signal to select it, and the software will tune it in for you. The software provides a tuning display which shows the radio signals that are receivable within the transceiver passband. This link will point to a very useful "Sights and Sounds" page that is useful to recognize these modes. There is also (see later paragraph) an automatic tuning option which can recognise and tune in most modes for you. You can also practise transmitting with the transceiver disconnected, listening to the sound of the signals coming from the computer. It is a matter of listening to the signal, and observing the appearance of the signal on the tuning display. ![]() Recognising the different modes comes with experience. How do I recognise and tune in the signals? It is difficult to advise which mode is best for each particular occasion, and experience plays an important role. While in many cases several different modes might be suitable, having a choice adds to the operating pleasure. Other factors such as available band space, operating speed and convenience, noise level, signal level and available power also affect the choice of mode. Experience has shown that particular modulation systems, speeds and bandwidths suit different operating conditions. There are strong interactions between different signals arriving from different paths. HF propagation is very dependent on the ionosphere, which reflects the signals back to earth. Software such as Fldigi makes this very simple as most of the procedural business is set up for you using the Function Keys at the top of the keyboard. Some modes also offer built-in automatic error correction.ĭigital Mode operating procedure is not unlike Morse operation, and many of the same abbreviations are used. These chat modes allow multiple operators to take part in a net.īecause of sophisticated digital signal processing which takes place inside the computer, digital modes can offer performance that cannot be achieved using voice (and in some cases even Morse), through reduced bandwidth, improved signal-to-noise performance and reduced transmitter power requirement. In this context, we are talking about modes used on the HF (high frequency) bands, specifically chat modes, those used to have a regular conversation in a similar way to voice or Morse, where one operator talks for a minute or two, then another does the same. It also controls the transmitter, changes modes as required, and provides various convenient features such as easy tuning of signals and prearranged messages. The computer acts as modem (modulator - demodulator), as well as allowing you to type, and see what the other person types. What is a Digital Mode?ĭigital Modes are a means of operating Amateur radio from the computer keyboard. Fldigi includes all the popular modes, such as DominoEX, MFSK16, PSK31, and RTTY.įldigi is available for multiple computer operating systems FreeBSD™ Linux™, OS X™ and Windows™. The software also controls the radio by means of another connection, typically a serial port.įldigi is multi-mode, which means that it is able to operate many popular digital modes without switching programs, so you only have one program to learn. Fldigi operates (as does most similar software) in conjunction with a conventional HF SSB radio transceiver, and uses the PC sound card as the main means of input from the radio, and output to the radio. What is Fldigi?įldigi is a computer program intended for Amateur Radio Digital Modes operation using a PC (Personal Computer). The Initial Configuration pages are particularly helpful. You can also access it from within the Fldigi program from the Help menu item. You should learn how to make best use of the program by reading the Online Documentation. Of necessity, this Beginners' Guide contains only as much as you need to know to get started. How do I recognise and tune in the signals?. ![]()
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