wiki:Documentation/FAQ
Last modified 8 months ago Last modified on 08/12/13 23:55:31

Fldigi FAQ

Here you can find answers to some of the most frequently asked questions about Fldigi. If you have questions not answered on this page, you can ask on the mailing lists.

You are invited to edit this page and add FAQs on topics that you are familiar with or have answered yourself. However, please do not add unanswered questions and try to keep the answers brief. Long answers should be in separate pages under Documentation/ and linked to below.


  1. General information
    1. What is fldigi?
    2. Is fldigi free software?
    3. How do I obtain fldigi?
  2. Installing Fldigi
    1. What are the minimum hardware requirements for fldigi?
    2. Which operating systems does fldigi run on?
    3. fldigi crashes after upgrading on Windows
    4. I want to run the Linux version of fldigi. Do I need to build it from source?
    5. Where can I find the alpha (test) releases?
  3. Using fldigi
    1. How can I toggle transmit and receive without using a macro?
    2. Why does fldigi access the Internet?
    3. How can I receive SYNOP and SHIP Weather reports ?
    4. How do I decode SYNOP weather reports ?
  4. Miscellaneous
    1. Is there any material I can use to present fldigi at my club meeting?


General information

What is fldigi?

Fldigi (Fast Light Digital Modem Application) is a program for transmitting and receiving signals via a radio transceiver. It includes support for most digital modes used on the amateur radio bands, as well as many related functions (logging, transceiver control, sound card calibration and frequency analysis).

Is fldigi free software?

Fldigi is Free Software and can be modified and redistributed under the terms of the License.

How do I obtain fldigi?

Fldigi can be found at the main web site.

Installing Fldigi

What are the minimum hardware requirements for fldigi?

We recommend at least a 1.2 GHz processor for most digital modes, and at least a 1.6 GHz processor for CPU-intensive modes like DominoEX and Thor. A faster CPU may be needed for multiple PSK decoding.

Fldigi can interface with many transceiver models via Hamlib and RigCAT.

You can also make use of flrig which is a stand alone application of the W1HKJ FLTK suite available on the Download page at w1hkj.com.

Which operating systems does fldigi run on?

Fldigi should run on all POSIX/X11 systems (*BSD, Linux, Solaris, etc.). It has also been ported to Mac OS X (10.4 or newer) and Windows (2000 or newer).

fldigi crashes after upgrading on Windows

Seems to be a common complaint and usually caused by trying to upgrade and skip several version changes. fldigi maintains it's configuration (long term settings) and status (state on last execution) files in it's own files folder.

  • On XP C:\"Documents and Settings\<urlogin>\fldigi.files\"
  • On W2K C:\"Documents and Settings\<urlogin>\fldigi.files\"
  • On Vista/Win7 C:\User\<urlogin>\fldigi.files\
  • On OS X /home/<login_name>/.fldigi
  • On Linux /home/<login_name>/.fldigi

Delete these two files located in the files folder: fldigi_def.xml and fldigi.prefs

It is not necessary to delete any other files or folders. If you do then you will probably lose your macro and logbook files.

Start the new fldigi and you will be presented with the start-up wizard.

I want to run the Linux version of fldigi. Do I need to build it from source?

No, building from source is not necessary unless you are modifying the code or debugging.

Fldigi is available as a pre-compiled binary and is on the download page, there is also a README that gives detailed instructions on installing. Ubuntu users may also download it using the software manager.

Where can I find the alpha (test) releases?

Source and binaries for the latest alpha release can be found at http://www.w1hkj.com/alpha. Alpha releases may have bugs; we advise you to make a backup copy of your fldigi configuration files.

If you use the alpha releases we recommend that you also subscribe to the fldigi-alpha mailing list, or read the announcement emails from the list's Archives.

Using fldigi

How can I toggle transmit and receive without using a macro?

Press Ctrl-T/Ctrl-R or the Pause key inside the transmit text area.

Why does fldigi access the Internet?

Short answer: it doesn't unless you tell it to.

Users of certain "personal firewall" programs for Windows (e.g., Zone Alarm) may see alerts about fldigi's network usage. While fldigi does open several network sockets, they are all bound to the localhost address and therefore only accessible by programs running on the same machine. The sockets are used for:

  • Communication with XML-RPC clients (e.g., flrig)
  • Communication with ARQ clients (e.g., flarq, PSKmail)
  • Some internal messaging

The latter means that fldigi will generate network traffic on the loopback interface even when no other programs are using fldigi's network servers.

Note that fldigi also has features that involve actual internet access (e.g., the PSK Reporter module), but those are activated by the user.

How can I receive SYNOP and SHIP Weather reports ?

SYNOP (Also called FM-12) is a numerical code used for reporting weather observations. These reports, along with FM-13, i.e. SHIP data, are also transmitted are transmitted in RTTY by the Deutscher Wetterdienst (German Meteorological) at regular times.

It is necessary to click on the fldigi Rv (Reverse) button on the bottom menu bar, lower right corner of the Fldigi screen. That is, the signal must be inverted and the mark and space put at the right place.

The ( mode and frequencies ) in F1B are, in LSB with 50 Bauds:

147,300 kHz+/- 42,5 HertzDDH 47
4583,000 kHz+/- 225 Hertz DDK 2
7646,000 kHz+/- 225 Hertz DDH 7
10100,800 kHz+/- 225 Hertz DDK 9
11039,000 kHz+/- 225 Hertz DDH 9
14467,300 kHz+/- 225 Hertz DDH 8

SYNOP reports look like sequence of words, mostly group of five numbers, such as:

956
SMPO60 LPMG 241200 CCA
AAXX 24121
08522 32570 49902 10250 20176 30131 40199 52002 82200 222// 00240
 314// 40301 333 82820 83099 555 50004 60005=

Because RTTY code represent letters and numbers with shift code, it might happen that a transmission error unexpectedly shifts numbers to letters. It is possible to turn this behaviour off in the RTTY configuration by turning off the "Unshift on Space", these spaces being the ones between group of words. That way, it keeps the numbers displayed in all circumstances.

How do I decode SYNOP weather reports ?

Fldigi contains a SYNOP decoder, a pice of software which translate these cryptic codes into clear weather reports. When these reports can be associated to a longitude/latitude pair, the report is written in a KML file which can be displayed in Google Earth.

During installation of fldigi, you were prompted to download a couple of data files: There are necessary for decoding many reports.

Much more information available here: SYNOP reports in Fldigi

Miscellaneous

Is there any material I can use to present fldigi at my club meeting?

You can find a presentation about fldigi and NBEMS at the articles page.