Xastir—Open-Source Client for the Automatic Packet Reporting System
Getting an Amateur Radio License
Many people think of Amateur Radio operators as old guys sitting in the basement in front of a radio with glowing tubes, tapping on a Morse code key.
The good news is that Morse code is no longer a requirement in the US. Tubes have been replaced by transistors, integrated circuits, embedded processors and software defined radio (SDR). We have satellites in orbit, had digipeaters on the international space station and (now expired) MIR, and do EME and EVE signal bounces (Earth→Moon→Earth and Earth→Venus→Earth). It's not your grandpa's ham radio anymore!
License types have been streamlined to three: Technician Class, General Class and Amateur Extra Class. Each license grants additional privileges, mostly in the form of additional allowed frequencies. The entry-level Technician Class allows you to participate in the APRS network described in this article along with many additional privileges.
Many barriers to getting a license have been removed. Tests are no longer given by the FCC field offices, but by volunteer examiners. In large urban areas, there may be multiple places to take a test each month. Practice tests are available on-line (try www.qrz.com and others). For more information about Amateur Radio licensing, or where to find testing in your area, go to www.arrl.org and click on Licensing.
Note: the information above is US-centric. Each country has a regulatory body governing Amateur Radio and often a national Amateur Radio organization. Contact your national organization or regulatory body for specific details regarding Amateur Radio licensing in your country.
Equipment Needed for Xastir/APRS
1) Minimum requirements: a live Internet feed, Linux (or another UNIX/UNIX-like operating system) and Xastir.
2) Adding Amateur Radio to the mix: Linux, a soundcard, the soundmodem package, a two-meter ham radio, a valid ham radio license and Xastir. It is possible to configure this setup with or without the Linux AX.25 library.
Note that it's completely legal to own Amateur Radio equipment without an Amateur Radio license, as long as you use the equipment only to receive. Transmitting on Amateur Radio frequencies without a license is blatantly illegal, and the community is capable (and motivated!) to hunt down troublesome rogue transmissions, and the FCC has a long tradition of prosecuting miscreants.
3) A more reasonable station: Linux plus a hardware TNC in KISS mode, a two-meter radio and a valid license. Again, one can configure with or without the Linux AX.25 library.
To build a portable or mobile tracker, many options exist that don't involve carrying around a full-blown laptop. Go to info.aprs.net, and click on Hardware to see loads of options.
Xastir Home: www.xastir.org
Mailing Lists: lists.xastir.org/mailman/listinfo
SourceForge Project: sourceforge.net/projects/xastir
Soundcard Wiki Page: www.xastir.org/wiki/index.php/HowTo:SoundModem
AX.25 Wiki Page: www.xastir.org/wiki/index.php/HowTo:AX.25
SAR Page: www.eskimo.com/~archer/xastir/SAR.html
APRS Main Pages: aprs.org
APRS Wiki: info.aprs.net
Practice Tests: www.qrz.com
Naval Academy Radio Club's 2008 Army/Navy Football Run LIVE Tracking Page: www.aprs.org/football.html
Photo of the Original GPS Tracker Installed in the Football Helmet for Runners Who Traveled from an Annapolis Pep Rally to the Stadium in New York: www.usna.edu/Users/aero/bruninga/foot.html
APRS Tracking 1993 Football Run: www.usna.edu/Users/aero/bruninga/football.html
Curtis E. Mills, WE7U, became active in packet radio in the mid-1980s, creating a receive-only station from a radio, a single-chip interface circuit and custom assembly code. He's active in search and rescue and contributes to Firenet, Xastir, SmartPalm and gpsbabel development. Other interests are hiking and bow hunting when his kids aren't running him ragged. He's employed as an engineer at Fluke Corporation. Reach him at email@example.com or as WE7U-3 on APRS. He also can be found on Xastir, NWAPRS and APRSSIG lists.
Steve Stroh, N8GNJ, had his first experiences with TCP/IP networking via Amateur Packet Radio on the Puget Sound Packet Radio TCP/IP network (WETNet) in the late 1980s. From hanging out with that bad crowd of techies, Steve became a sysadmin (on systems lesser than Linux) and in 1997, began writing about broadband wireless Internet access based on his practical experience with wireless gained from being a ham. He's looking forward to some winter projects, including diving deep into open-source wireless mesh networks, embedded ARM-based Linux systems, running IPv6 over Amateur Packet Radio and getting a number of radios back on the air after a long absence. Steve can be reached at firstname.lastname@example.org.
Laura Shaffer Mills studied engineering, but prefers writing software in any convenient language. She hopes to learn something new from every project and particularly enjoys solving problems that no one else had found. She relaxes with wire harp or tatting, since both are quite rare. Laura lives with her husband and three daughters and can be found at www.redwriteblue.com.
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