Requirements Installation Getting Started Operating Special Keys
FLDIGI is a computer program intended for Amateur Radio Digital Modes operation using a PC (Personal Computer). 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. These are audio-frequency signals. The software also controls the radio by means of another connection, typically a serial port.FLDIGI 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 includes all the popular modes, such as DominoEX, MFSK16, PSK31, and RTTY.
Unusually, FLDIGI is available for multiple computer operating systems; Windows™, various LINUX™ distributions, FreeBSD™ and OS-X™.
Digital Modes are a means of operating Amateur radio from the computer keyboard. The computer acts as 'modem' (modulator - demodulator), as well as allowing you to type, and see what the other person types. It also controls the transmitter, changes modes as required, and provides various convenient features such as easy tuning of signals and prearranged messages.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. These chat modes allow multiple operators to take part in a 'net'.
Because 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. Some modes also offer built-in automatic error correction.
Digital Mode operating procedure is not unlike Morse operation, and many of the same abbreviations are used. 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. These are easy to learn.
HF propagation is very dependent on the ionosphere, which reflects the signals back to earth. There are strong interactions between different signals arriving from different paths. Experience has shown that particular modulation systems, speeds and bandwidths suit different operating conditions.Other factors such as available band space, operating speed and convenience, noise level, signal level and available power also affect the choice of mode. While in many cases several different modes might be suitable, having a choice adds to the operating pleasure. It is diffcult to advise which mode is best for each particular occasion, and experience plays an important role.
You might consider purchasing 'Digital Modes for All Occasions' (ISBN 1-872309-82-8) by Murray Greenman ZL1BPU, published by the RSGB, as this gives a good insight into each mode and its capabilities. The book is also available from FUNKAMATEUR and CQ Communications.
Recognising the different modes comes with experience. It is a matter of listening to the signal, and observing the appearance of the signal on the tuning display. You can also practice transmitting with the transceiver disconnected, listening to the sound of the signals coming from the computer. There is also (see later paragraph) an automatic tuning option which can recognise and tune in most modes for you.The software provides a tuning display which shows the radio signals that are receivable within the transceiver passband. Using a 'point and click' technique with the mouse, you can click on the centre of a signal to select it, and the software will tune it in for you. 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!
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. For this feature to work, not only do you need to enable the feature in the receiver, but in addition the stations you are wishing to tune in need to have this feature enabled on transmission. Other programs also offer this RSID feature as an option.
Of necessity, this Beginner's Guide contains only as much as you need to know to get started. You can always read the details and learn how to make best use of the program by reading the Online Documentation. You can also access it from within the FLDIGI program from the HELP Menu item.
- Computer
- Pentium™ 3 or 4, Celeron™, or equivalent, 750MHz or better, 256MB RAM or more. Faster computers can give better performance.
- Operating System
- Windows XP SP2 (Home or Pro), LINUX distributions such as Debian, Ubuntu, Kubuntu, Mandriva, Mandrake, SuSE, Puppy Linux, or FreeBSD. FLDIGI can be home compiled for other distributions. FLDIGI does not support Windows 98 or older, and may not work with Windows VISTA.
- Other Requirements
- Computer serial port (or USB serial port) for rig control
- Optional serial CAT (Computer Aided Tuning) computer control
- About 5MB of drive space is required for program files
- Internet connection will allow direct connection to the online help files and your online callsign server subscription.
- A radio interface to the sound card and serial port, such as the RigBlaster™ or similar. You can make one yourself.
- A modern HF SSB transceiver, with or without CAT control. For some modes, frequency stability is very important (preferably less than 1Hz drift per over), and the difference between transmit and receive frequencies should also be low (less than 1Hz). Tuning steps should be 100Hz or less. Most commercial synthesized transceivers made in the last 20 years will meet these requirements.
- Locate and download the correct archive for your operating system from the FLDIGI web site.
- Create a suitable folder on your hard drive (for example Programs/FLDIGI) and unzip the archive into this folder.
- Right-click on the executable fldigi.exe, select 'Create Shortcut', and drag the resulting shortcut either to the desktop or to a suitable place in the menu structure.
- Double-click on this new shortcut to start the program. You're in business!
- Delete the shortcut you made during installation
- Repeat the installation process described above, using the same folder. The new program will over-write the old.
- Make a new shortcut as described above.
- Delete the shortcut you made during installation
- Locate the program folder you made during installation, delete the contents, and then delete the folder.
- Use the menu Configure/Defaults/Sound Card Audio Devices tab to select the sound card you wish to use. You can ignore the other tabs for now.
- Use the menu Configure/Defaults/Operator item to set the user name, callsign, location and so on.
- Use the menu Configure/Defaults/Rig Ctrl item to set how you will control the rig. Set 'Ptt' to 'TTY'. If you will control the rig via a serial port, select the COM port you will use, and select which line controls PTT. If in doubt, check both RTS and DTR. You MUST then press the Initialize button.
- If you plan to use CAT control of the rig via the COM port, check 'userigCAT'. If in addition you wish to use PTT control via CAT, also then check 'rigCAT PTT'. You MUST then press the Initialize button.
- Use the menu Configure/Defaults/Misc item to set whether you wish to transmit RSID data at the start of each over (this is for the benefit of others, this setting does not affect RSID reception), and whether you have a slow computer (under 1000MHz) or not. The receiver decoding strategy uses less processor power in 'Slow cpu' mode. If you plan to regularly use the RSID feature on receive, you must leave the 'Start New Modem at Sweet Spot' item unchecked.
- Each of the modems can be individually set up from the Configure/Modems multi-tabbed dialog. You need not change anything here to start with, although it might be a good idea to set the 'secondary text' for DominoEX ('Dom' tab) and THOR ('Thor' tab) to something useful, such as your call and locator. (Secondary text is transmitted when the text you type does not keep up with the typing speed of the mode - this handy text appears in a small window at the very bottom of the screen). Note that this set of tabs is also where you set the RTTY modem speed and shift, although the default values should be fine for normal operation.
- Use the menu Configure/Save Config item to save the new configuration.
- Use your sound card 'Master Volume' applet to select the sound card, the Wave output and set the transmit audio level. You can check the level using the TUNE button, top right, beyond the Menu.
- The 'Volume' applet can usually be opened by START/Run... and enter 'sndvol32', or from the Control Panel.
- Use your sound card 'Recording Control' applet to select the sound card, the line or mic input and set the receiver audio level. Watch the waterfall display for receiver noise when setting the level. If you see any dark blue noise, you have the right input and about the right level. The actual setting is not very important, provided you see blue noise. If the audio level is too high, the little diamond shaped indicator (bottom right) will show red. The waterfall may also show red bands. Performance will be degraded if the level is too high.
- The 'Record' applet can usually be opened by START/Run... and enter 'sndvol32 /r', or from the Control Panel. If opened from the Control Panel, you'll end up with the Master Volume applet, and need to switch using Options/Properties, and selecting the 'Recording' radio button.
Double-click on the FLDIGI shortcut to start the program. A window with three main panes will appear. Study it carefully as you read these notes. From top to bottom, these are the RECEIVE pane (orange), the TRANSMIT pane (light blue), and the WATERFALL pane (black). At the top is the collection of entry items which form the LOG DATA, and at the very top, a conventional drop-down MENU system, with entries for Files, Op Mode, Configure, View and Help.
This is where the text from decoded incoming signals is displayed, in black text. When you transmit, the transmitted text is also displayed here, but in red, so the RECEIVE pane becomes a complete record of the QSO. The information in this pane can also be logged to a file.
This is where you type what you want to transmit. The mouse must click in here before you type (to obtain 'focus') otherwise your text will go nowhere. You can type in here while you are receiving, and when you start transmitting, the text already typed will be sent first. This trick is a cool way to impress others with your typing speed! As the text is transmitted, the text colour changes from black to red. At the end of the over, all the transmitted text (and any as yet not transmitted) will be deleted.
This is the main tuning facility. There are two modes, 'Waterfall' and 'FFT', selected by a button in the CONTROL group. For now, leave it in 'Waterfall' mode, as this is the easiest to tune with, and gives the best identification of the signal.
- 'Waterfall' is a spectrogram display, of signal strength versus frequency, over passing time. The receiver passband is analysed and displayed with lower frequencies to the left, higher to the right. Weak signals and background noise are dark while stronger signals show as brighter colours. As time passes (over a few seconds), the historic signals move downwards like a waterfall.
- 'FFT' is a spectrum display, simply the mean signal strength versus frequency. Again frequency is displayed from left to right, but now the vertical direction shows signal strength and there is no brightness or historic onformation.
Using this group of entry boxes, you can keep a log of your QSOs. At the left are two 'Frequency' boxes. If you use CAT control to operate your transceiver, the dial frequency is recorded automatically in the lower box; otherwise you can type it manually or select (botton to the right) from a list of common frequencies. The audio frequency from the waterfall is added to this value and displayed in the upper box - assuming your rig is calibrated correctly, this is the true centre frequency of the station you are in QSO with. You can't type in the upper box.
At the very top of the program window is a conventional drop-down menu. If you click on any of the items, a list of optional functions will appear. Keyboard menu selection is also provided. Where underscored characters are shown in the menu, you can select these menu items from the keyboard using the marked character and <Alt> at the same time, then moving around with the up/down/left/right keys. Use <Esc> to quit from the menu with no change. These menu functions are:
At the bottom of the list are two 'modes' which aren't modes at all, and do not transmit (see Online Documentation for details). WWV mode allows you to receive a standard time signal so the beeps it transmits can be used for sound card calibration. Freq Analysis provides just a waterfall display with a very narrow cursor, and a frequency meter which indicates the received frequency in Hz to two decimal places. This is useful for on-air frequency measurement.
This line of buttons provides user-editable QSO features. For example, the first button on the left sends CQ for you. Both the function of these buttons (we call them MACROS) and the label on each button, can be changed. Select each button to use it by pressing the corresponding Function Key (F1 - F12, you'll notice the buttons are grouped in patterns four to a group, just as the Function Keys are). You can also select them with a left-click of the mouse. If you right-click on the button, you are able to edit the buttons label and its function. A handy dialog pops up to allow this to be done. There are many standard shortcuts, such as <MYCALL> which you can use within the Macros. Notice that the buttons also turn the transmitter on and off as necessary.You can just about hold a complete QSO using these buttons from left to right (but please don't!). Notice that at the right are two spare buttons you can set as you wish, and then a button labelled '1'. Yes, this is the first set of FOUR sets of Macros, and you can access the others using this button, which changes to read '2', '3', '4' then '1' again (right-click to go backwards), or by pressing <Alt> and the corresponding number (1-4, not F1-F4) at the same time.
If you REALLY mess up the Macros and can't see how to fix them, just close the program without saving them, and reopen it.
The line of buttons under the waterfall is used to control the program (as opposed to the QSO). If you hover the mouse over these buttons, you'll see a little yellow hint box appear which tells you what each button does.The Id? button turns on the receive RSID (automatic mode detection and tuning) feature. When in use, the button turns yellow and no text reception is possible until a signal is identified, or the feature is turned off again. If you plan to use the RSID feature on receive, you must leave the 'Start New Modem at Sweet Spot' item in the Menu Configure/Defaults/Mics tab unchecked.
The next three buttons control waterfall behaviour. The first switches between Waterfall and FFT modes; the next sets the scale zoom factor (visible display width, x1, x2 or x4); the third selects the waterfall speed. NORM or SLOW setting is best unless you have a very fast computer.
The next three buttons move the waterfall left and right, followed by two (either side of a number, the audio frequency in Hz) which control the receiving frequency (they move the red cursor lines).
You can also adjust the signal level over which the waterfall works. The default range is from 0dB downwards 70dB (i.e. to -70dB). Both of these values can be adjusted to suit your sound card and receiver audio level.
The M button allows you to store or recall the current frequency (see the Online Documentation for details). The Lk button locks the transmit frequency (fixes the red cursors), and the Rv button turns the signal decoding upside down (some modes are sideband sensitive, and if they are the wrong way up, can't be received correctly). Remember to turn this one off when you're done, or you won't receive anything! If every signal you hear is upside down, check your transceiver sideband setting.
The T/R button forces the transmitter on or off - use this with care, as it will stop transmission immediately, losing whatever is in the buffer (what you have typed in the Transmit pane), or start it immediately, even if nothing is ready to transmit.
There are two further controls in the bottom right corner of the program, to the right of the Status line:
At the very bottom line of the FLDIGI window is a row of useful information. At the left is the current operating mode. Next (some modes) is the measured signal-to-noise ratio at the receiver, and (in some modes) the measured signal intermodulation level (IMD).The larger central box shows (in DominoEX and THOR modes) the received 'Secondary Text'. This is information (such as station identification) which is transmitted automatically whenever the transmitter has completed all user text that is available to send. It is transmitted using special characters, and is automatically directed to this special window. Secondary text you transmit is also shown here. This box changes size when you enlarge the program window.
Operating procedure for digital modes is similar to that for Morse. Some of the same abbreviations are used. For example, at the beginning of an over, you might send 'VK3XYZ de WB8ABC' or just 'RR Jack' and so on. At the end of an over, it is usual to send 'ZL1ABC de AA3AR K', and at the end of a QSO '73 F3XYZ de 3D2ZZ SK'. When operating in a group or net it is usual to sign 'AA3AE es gp de ZK8WW K'.The Macros are set up to control the transmitter as necessary, but you can also switch the transmitter on at the start of an over with <Ctrl> and T or the TX macro button, and off again with <Ctrl> and R or the RX macro button. If you have Macros copied into or text already typed in the Transmit pane when you start the transmitter, this is sent first.
- Hint: Some Function Key Macro buttons have graphic symbols on them which imply the following:
- >> The transmitter comes on and stays on when you use this button/macro.
- || The transmitter goes off when the text from this button/macro has been sent.
- >| The transmitter comes on, sends the text from this button/macro, and goes off when the text from this button/macro has been sent.
- Hint: When typing text, the correct use of upper and lower case is important:
- Modes such as RTTY and THROB have no lower case capability.
- In most other modes, excessive use of upper case is considered impolite, like SHOUTING!
- Modes such as PSK31, MFSK16, DominoEX and THOR use character sets which are optimized for lower case. You should use lower case as much as possible in these modes to achieve maximum text speed. In these modes upper case characters are noticeably slower to send and also slightly more prone to errors.
Most digital modes do not require much transmitter power, as the receiver software is very sensitive. Many modes (PSK31, THROB, MT63) also require very high transmitter linearity, which is another reason to keep transmitter power below 30% of maximum. Some modes (Hellschreiber, Morse) have high peak power output, which may not indicate well on the conventional power meter, another reason to keep the average transmitted power low to prevent a very broad signal being transmitted.
- Hint: Where possible, use the area above 1200Hz on the waterfall.
- Below 1200Hz the second harmonic of the transmitted audio will pass through the transmitter filters.
- When using lower frequency tones, adjust the transmitter and audio level with great care, as the second (and even third) harmonic will appear in the transmitter passband, causing excessive signal width.
- A narrow (CW) filter in the rig is no help in this regard, as it is only used on receive. When you do use a narrow filter, this will restrict the area over which the receiver and transmitter will operate (without retuning of course). Try adjusting the passband tuning (if available).
- Keep the sound card audio level to a minimum and set the transmitter gain to a similar level used for SSB.
When using this program, as with most other digital modes programs, tuning is generally accomplished by leaving the transceiver VFO at a popular spot (for example 14.070MHz, USB), and performing all the 'tuning' by moving around within the software.Wider digital modes (MT63, Olivia) can be tuned using the rig if necessary, as tuning is not at all critical. The software tuning still operates, but because the signal is so wide, there is limited ability to move around in the waterfall tuning.
- Hint: You MUST NOT use RIT (Clarifier) when using digital modes.
- With RIT on, you will probably have to retune after every over.
- Use of the RIT will also cause the other station to change frequency, and you will chase each other across the band.
- Older transceivers without digital synthesis may have an unwanted offset (frequency difference) between transmit and receive frequencies. Such rigs should not be used for digital modes.
Several special keyboard controls are provided to make operating easier.