Methods, Modes, and Technologies
The many aspects of Ham Radio
This page serves as a starting point for exploring the different aspects of ham radio. It is by no means and in-depth treatment of any of the subjects or modes but an overview and a starting point for those who may want to expand their horizons. Members are encouraged to contribute. Pick a topic, do a small write-up, include your best links on the subject and I'll take care of creating a web page here for the members to enjoy. Any satellite enthusiasts out there?
APRS - Automatic Packet Reporting System
Some of us may think the "P" in APRS stands for "position" but the creator of the system, Bob Bruninga, WB4APR, confirms that it always stood for "Packet".
Take a VHF radio transmitting on 144.39 MHz (in the US) and a TNC like the Tiny Trak or the OpenTracker, add a GPS and you have an APRS tracker.
APRS packets can also contain a short message, a text based status string, even the ability to send a properly formatted message into the internet so that you can send a short text message to any regular email address.
Once your packet is picked up by an I-Gate, your position is entered into the APRS database and can be viewed on a number of web sites. FINDU.COM was one of the original ones.
My favorite has become APRS.FI APRS.FI will ask you to sign on with any name you want to use. If you use your call letters, it will open a Google map and load all the APRS positions in your area. You can pan and zoom this map like any Google map. A unique feature is that this database retains 6 months of data. In the summer, we carry an APRS tracker on our sailboat. So, for another few months, if you look for W3TMC-5 you will see the last time we had the tracker on the boat.
This link displays the last sail we made. You will notice the blue text at the right under "Select a Day" where you can select other days. To plot all of the points of that day, you must select "24hrs" at the top of the column.
See if you can display 24hrs of positions from W3TMC-5 on Oct 4, 2008. Another neat feature of this system is the telemetry text string. If you click on any of the red position dots, you will see the speed data, the course, temperature (inside the TNC), and the system voltage. So if we have a QSO and I tell you we are sailing along at 7 knots and you see the system voltage is 14 volts, you'll know the engine is running - hi!
The starting point to learn more about APRS is WWW.APRS.ORG