Tracking a Pico Balloon
Tracking Overview
The balloon tracker sends out two wspr messages periodically. Wspr is discussed below. Early balloons and a few current balloons use the ham APRS network. These work by the same method. Hams around the world receives the signals, decode them and then send them to as central database for mapping the position. Wspr messages go to wsprnet.org. APRS tracker data goes directly to APRS.fi. Movement from wsprnet.org to tracking is semiautomated if you register your flight on the lu7aa website. Otherwise, there are programs available to move the data.
WSPR Ham Radio Propagation Network
WSPR is a method of sending radio message using a ham radio. Many ham radio operators attempt to contact people around the world. Certificates are given for contacting 100 countries. These ham radio operators use WSPR to test how well radio signals are propagating around the world, Basically some operators transmit and others receive. All received messages contain the location of the transmitting station and are uploaded to a central database and used to plot on a map a line between the transmitting station and the receiving station. The software that is used by operators to decode the information in the radio signal is called WXJT-X. Balloon trackers send WSPR messages that are heard by the same ham operators, All decoded messages are uploaded to a central database Wsprnet.org.
The Wsprnet.org website can be used to see the latest location of a balloon. You can see a line on a world map from each of the stations that received your signal to the location of your balloon.
WSPRnet.org also provides a method to download this data which then can be uploaded to the tracking websites. This is semi-automated by lu7aa.org.ar website.
Tracking Websites
This ham network is used for all types of tracking and communication. It is typically used for tracking cars and bikes. The lu7aa.org.ar website automatically forwards spots to this APRS.fi. So balloons can also be tracked using this site.
The best tracking site. Amsat Argentina provides a wonderful service to the ballooning community. Its website downloads data from wspr.net and provides decoding for all of the tracker wspr formats. It then will plot the location of your balloon with links to other sites like wind speed and cloud cover. Also it uploads the data to APRS.fi and Soundehub. To use this for your balloon go to this site and fill in the information for your balloon.
This sites will automatically take balloon data from APRS.fi or it can be directly uploaded. In addition to plotting positions and path, it also provides a way to plot sensor data.
Path Prediction
NOAA provides a website that calculates the projected path of a balloon. Click here for instructions on how to use the site to get trajectory predictions.