The rapidly growing trend on the amateur bands now is in communicating using digital techniques. The digital modes have encompassed printed text, voice and image transmission. The technologies involved have progressed to the point where they are as reliable as their analog counterparts. Many advances have been made in recent years which results in weaker signal decoding and reliability under various kinds of band conditions.
Of course the main prerequisite for operating any of the digital modes is the need to have a computer in the hamshack. Many hams already have one which they use for logging, contesting, and other ham related activities, including surfing the web. Depending on what you want to do, the computer speed isnt all that important unless you want to run the newest image modes. For the text modes, where most of the activity is presently at, speed is not a concern.
Some of my digital programs that I am going to showcase here are linux based, but there are Windows equivalents. The Linux based program I use the most for text based communication is "fldigi", and in MY opinion, its the BEST program available on any operating system. It will run all the current text based modes, and it does it very well.
One day while surfing the linux sites, I came across a website that was put up by Dave, W1HKJ with some really good software he has written. He has software there covering the digital modes, logging, rig control, and other ham radio based utilities. I downloaded a number of his programs and run them, and they work great! Fldigi is his digital program, and its available as a binary for the Debian based as well as Redhat so you can compile your own. You can find Dave's software at W1HKJ. He has a complete description and help files available as well as screenshots... anything you want to know about the program.
Digital Slow Scan, as its referred to on the air basically is a means to transmit high quality images digitally. These pictures sent via "HD SSTV" are of VERY high quality, without the "noise lines" that occur while receiving analog images. The pictures are far sharper as well. This is one mode that you really have to take a look at.
This is an actual sample image that I have copied via digital SSTV. As you can see, the clarity is second to none. This picture took about 100 seconds to transmit on the 40 meter ham band.
The program I use for Digital SSTV is called "Easypal", and it is available here. It is the most advanced program available, and the reliability is VERY good. While youre on that site, I suggest you also download "SSTVPICS" as it makes sending images easier. These programs are Windows based, and to date, no linux versions are available.
I also have a "live action SSTV Cam". If I'm on the air or listening to the SSTV frequencies, this page will show the last few pictures I have received. The page updates itself every couple minutes, and if I'm actually on, and pics are being sent, they will update in real time.
A few years ago, a fellow by the name of Joe Taylor, K1JT created a program that was designed to be used on the VHF bands to aid the operator in detecting and copying extremely weak signals. This program will run several modes which work very well for different types of propagation on the VHF bands. FFT441 and JT6M work for meteor scatter, and JT65 and its variants work for tropo and moonbounce applications. These modes work so well that signals that are totally inaudible to the ear will print reliable copy. This program is the standard today for all extremely weak signal VHF communication.
WSJT can be installed in both the Windows and Linux operating systems. There is a binary available for the Debian variants. Before you use this program, I suggest you read Joe's online documentation, as this is a rather specialized mode, and it is a little bit complicated for the new user.
Joe's homepage can be found at http://physics.princeton.edu/pulsar/K1JT/. The online documentation for WSJT is available in .pdf format here.
I will provide some links as time permits that will lead you to the internet's best information on operating a digital station.
Stay tuned, and come back often! I have been adding stuff almost daily!