Software in use at K0SKW
I'm one of those people who can't leave well enough alone. My station is always changing -- including the computers that help everything run!
Ubuntu Linux
Ubuntu was chosen for a couple reasons. Mainly because it started popping up on Xastir's mailing list a lot. Ubuntu is a linux distrubution. It is open-source, and free. What more could a ham want! Linux is, in my opinion, the perfect match for amateur radio due to its experimental properties. Ubuntu takes those properties, and builds on them giving me one of the best distributions I've used to date. It is based on Debian, which has long been the ham's distribution of choice. Ubuntu seems to develop faster than Debian, as was one of the main goals of the Ubuntu project. The package management system in Debian/Ubuntu is top-notch for this stuff! I currently have Ubuntu doing ham radio stuff on an old Gateway laptop.
Fedora Linux
Fedora is something I've recently switched to at my dorm. I've got an old Dell desktop running Fedora 10, and so far like it a lot. It's similar to Ubuntu, however the philosophy behind it and the inner workings are a bit different. It's still a fine and stable OS and runs all the requisite ham applications just fine.
YFKlog
YFKlog is a console-based contact logging program coded in Perl. It uses a curses front end for a more polished look. I started playing around with this a couple weeks ago and do believe it to be my contact logging application of choice. Why? For one, I like the console-based interface. It means I can leave the program on one machine and use it from another using just SSH. YFKlog also uses a database for a backend, which can be either SQLite or MySQL. Using a database means you can do powerful things with outside applications, and it tends to be easier to backup and restore if you need to.
Xastir
Xastir is an open-source APRS mapping and messaging program. It has the ability to interface with many types of TNC's and use many types of maps. It is very versitle, and it runs on a Mac. If you run an operating system that can't run UI-View (Or you just don't want to, since Xastir can run on Windows), use Xastir
Xastir can be had at the Xastir homepage. It is also available from the package management on many different Linux distributions including Debian and of course Ubuntu, though these packages are a couple dot releases behind.
For Mac users, Xastir is available as a Mac OS X Installer file from Dana N1OFZ. Xastir is also available through Darwin Ports. I've been using the Darwin Ports version and it has worked well for me.
Minicom
Not a ham app, but useful to hams. I discovered Minicom recently thanks to someone on the Xastir mailing list. This program works much like Hyperterminal does on Windows. I needed a program to be able to configure my KISS-based TNC (a TNC-X with XTrack module) using one of my laptops. Minicom allows me to be able to connect to my TNC-X wonderfully and make configuration changes. I installed it via Darwin Ports on my mac, and the good ol' Synaptic on Ubutnu. This program also comes in handy every other time you need a serial console!
GPredict
For those "bird watchers", this program brings open-source satellite tracking to your linux-running computer. Satellite positions (as predicted by telemetry data) are displayed on a flattened map of the globe. Plug in the coordinates of your station, and GPredict can give you time estimates and alerts to birds flying overhead. With GRig, GPredict can swing your antennas to point right at a satellite as it passes! GPredict and GRig can be found at the ground-station page.
N3FJP's Net Manager
Although still for sale, Net Manager will not be updated. It's a gem of an application, though. I use it any time I run one of the Metro Area ARES nets. It is produced by N3FJP, a well known maker of specialty logging programs for a variety of contests. While this is a Windows application, it runs fine under Wine on the linux side. Net Manager is available from N3FJP's website under the "Other Specialty Logs" page.
Honorable Mentions
The apps listed here, you may or may not find on any of the systems here at K0SKW. Most of them are on here because of their development practices, and not necessarily for any usability issues.
UI-View
Quite possibly the most popular ham radio-related program for any operating system is UI-View. Rightfully so; it installs wonderfully on Windows systems, is packed with features, and it's free! The creator of UI-View passed away in 2004, but his legacy lives on in the user-base of UI-View. It is available here. Please note that given a choice between UI-View, and Xastir, I'd choose Xaster 6 days out of the week.
Ham Radio Deluxe
If there was something as popular as that oh-so-popular APRS program for Windows, it'd be Ham Radio Deluxe. HRD allows rig control functions of popular amateur transcievers. The interface will mimic the functions found on the front panel (and menus) of your transciever giving you easy access to everything. It even allows some remote functionality via the internet. More information on HRD can be found at the HRD homepage.