carried out during the flight
The radiogoniometry determined
route was remarkably accurate. Six out of seven of the calculated
points are within 10 km of the route transmitted by APRS. This
result was made possible thanks to about ten mobile or permanent
stations placed very far from Lons-le-Saunier at the Ballon d'Alsace.
(Ballon: round-topped mountain)
Nevertheless we lacked in a station located in the Langres or Villersexel District. It would have been used to take bearings at right angles.
The number 7 point corresponds to the last bearings read by faraway stations. After landing the beacon could be heard more than 50 km away.
The micro-beacon was heard within a radius of some kilometers.
Localisation by GPS/APRS
The localization with the help
of the boarded GPS and APRS perfectly took place up to 18000m.
Beyond this altitude the transmission became intermittent but
the data kept dependable. The highest measured altitude was 34434
m, close to the one calculated (33000m). After the bursting of
the balloon the transmission of the APRS frames was permanently
interrupted likely because of the inflating mantle which fell
back against the gondola and broke the APRS antenna. Numerous
stations followed the route of the REFFC-11 balloon on their APRS
screen. Some received live frames, sometimes from very far, others
through the network.
At the head-quarters in Devecey, 2 stations (F5HUP and F1SRX) were permanently following the course by APRS. For F5HUP all the frames transmitted by the balloon were wholly received live with a TNC2 and an IC02E on a three elements antenna made by F6IJC and installed in pursuit on the ATV antennas group.
The software used was UIVIEW 32 bits. On the opposite map drawn by Serge F5HUP, you can see the real route corresponding to the rise (blue dots) and the supposed route of the fall (red line). The rough change of direction was recorded at altitude 20000m.
For more details download the full map (300ko).
An example of APRS display: the balloon
at highest altitude
This extract of a screen copy was made from the F5HUP log (70 ko)
The highest speed (72,2 km/h) is equally shown on the segnent of the route studied during the time of the passage in the jet stream, between 9000 and 10000 m. Others OM sent us reports of following. Among the last ones F5IBH/90 uses XAST1R and Linux with a summary map.
Download map (85ko) and frames received (60 ko)