Project Strato flew their team’s 10th flight this past weekend with a successful launch and recovery. Unfortunately, we learned a hard lesson about proper radio packet configuration. We apologize to the APRS users for our excessive network traffic during the flight on 16 March 2014.

Our balloon flew two trackers, a Kenwood TH-D72 handheld radio and a modified MicroTrak tracker. These tracking devices were intended for two purposes: tracking the payload during flight as well as deriving altitude, ascent rate and descent rate data from the received packets.  These devices were configured with settings similar to the defaults which were designed for mobile terrestrial use.  However, our use of these settings while airborne, specifically the use of digirepeating paths and transmission rate, caused unreasonable congestion on the 144.390 MHz public use frequency.  We apologize to the many users of this wonderful service who were impacted by our unintentional misuse of the network.

We thank a couple HAMs, Stephen Smith WA8LMF and Dave Dobbins K7GPS in particular, for their help in identifying the problem and letting us to know to fix. Lynn W. Deffenbaugh posted  interesting plots of packets received and their distances, see below. Based on their feedback, our future flights will have properly configured multi hop settings and transmission rates.  There was also some pretty impressive flaming that occured on APRS related lists. Again, we apologize for the congestion and will not repeat.

Red lines represent direct reception.  Green are multipath packets.  It's quite clear how far the packets from the flights reached.
Red lines represent direct reception. Green are multipath packets. It’s quite clear how far the packets from the flights reached.

Fortunately, the rest of the flight was a success. As a training mission, students gained valuable hands on experience in developing and flying. They set an internal team altitude record of greater than 104,000 feet. Their inertial measurement unit measured accelerations and rotations for flight dynamics modeling. Flight operations went well despite the wind and cold. Recovery was good.

Launch, Strato Flight #10.
Launch, Strato Flight #10.

We look forward to future flights that will continue to flight test new technologies and train the next generation of engineers. We appreciate the help and advise from our neighbors and mentors. Thanks again!

Strato Flight – 16 March 2014