The ax25-apps package contains programs for the hamradio protocol AX.25 that would be used by normal users (as opposed to network daemons). While not essential, these programs are usually installed if you want to connect to amatuer packet radio networks. Generally it is a good idea to also get the ax25-tools package so you can configure the hamradio ports. This package includes call, listen, ax25ipd and ax25rtd.
The ax25-tools package contains the tools that you need to get going with AX.25 for Linux. AX.25 is a network protocol that is used by hamradio operators across packet radio wireless links. This package contains the network tools to configure hamradio interfaces and some of the hamradio specific network daemons. In addition to programs that understand AX.25, they also work with ROSE and Net/ROM hamradio protocols.
DXSpider is a Ham Radio program that connects to other similar programs by radio or the internet and provides a real-time information service to Ham Radio operators rather like IRC. It is designed to become a complete replacement for the original DOS implementation written by Dick Newell AK1A.
sctl is used to control the Bearcat BC895xlt, BC245, BC780, and Radio Shack PRO-2052 trunk tracking scanners. It can read and set memory contents and a numerous settings, and will display and change the current status (e.g. scanning, trunk scanning, etc.). It can also download/store and upload memory bank contents.