Day 7 report, 25-Sep-2016
Day 6 report, 24-Sep-2016
Day 5 report, 23-Sep-2016
Day 4 report, 22-Sep-2016
Day 3 report, 21-Sep-2016
Day 2 report, 20-Sep-2016
Day 1 report, 19-Sep-2016
Photos of the launch
The map below is updated automatically with the latest received position during the balloon's flight. During the balloon's night time the battery is quickly depleted, so from just after sunset there are no more reports until daylight.
NOTE: the RED line shows actual position reports received from the balloon during the day. The BLUE line is an interpolation at night based on the NOAA predictions. There were no position reports from the end of Day 2 until the start of Day 6. The blue track from the last reported position in the Atlantic is the 48-hour NOAA prediction. The North-South (approximately) GREEN lines are the arc of the likely position of the balloon at the end of days 4 (through Tunisia) and 5 (through Syria), based on the assumption that transmissions stop when the sun is below 15 degrees above the horizon. The green line leading up to the start of day 6 (just East of Turkmenistan) joins the first day 6 position report to the end of the 48-hour NOAA prediction and is pure speculation.
Nothing was heard from S17 at all today. S17 might have landed. Or perhaps it just hasn't been received, because it is flying in a part of the world where there are not many receiving stations, and we know the GPS is flakey, so the timing and frequency may be off.
I will write further updates here IF and WHEN S17 appears again.
Good news today for S17, the GPS booted up correctly in the morning and reported the position all day. Then the BAD news: when S17 woke up the first position report, over the Caspian sea, put the altitude at 3,600m. MUCH too low! Each of the next two reports, it dropped another 200m. There was some nail-biting. But miraculously S17 started gaining altitude again, climbing steadily over the next 2 hours to reach around 10,500m again. Most probably the balloon entered a high altitude cloud that was in the area. See the weather map below - the cloud is the red-circled thing right in the top right corner over the Caspian sea. In the cloud the balloon would have collected moisture, weighing it down and starting the descent. However perhaps as it came lower, the moisture dried off and it could gain altitude again. The graph below shows the beginning of S17's 6th day!
Thereafter the day was uneventful - S17 continued East through Turkmenistan, Kazakhstan and Uzbekistan. The NOAA prediction (see below) shows a steady journey East over China, North Korea and the northern part of Japan.
S17 flew again all day without any update to the position, and without the GPS setting the time etc. Today the clock was 60 seconds fast so by setting the PC clock off-time by 60 seconds it was possible for some stations to receive it (special thanks to Alan G4ZFQ for this and for tracking S17 all day). With the information of the last reception report occurring at 14:46Z it was possible for Dave to make a guess of where the balloon might be. On the assumption that the solar voltage will fail and cause the system to shut down when the sun is below an angle of 15 degrees, the balloon should be somewhere around the second green curve shown on the tracking map, see above, the line passing through Syria.
S17 flew again all day without any update to the position, and without the GPS setting the time etc. It was possible to receive S17 by setting your PC clock 10 seconds fast of usual. Thanks to Euan M0GBZ and Alan G4ZFQ for discovering this and also tracking S17 all day. With the information of the last reception report occurring at 16:50Z it was possible for Dave to make a guess of where the balloon might be. On the assumption that the solar voltage will fail and cause the system to shut down when the sun is below an angle of 15 degrees, the balloon should be somewhere around the red curve shown on the map below. Dave thinks it is probably somewhere around the Italian island of Sardinia (the red circle on the map).
S17 is still flying today, but the GPS did not start up properly at the beginning of the day. Maybe the way the battery voltage increased did not properly boot up the GPS and it got stuck somehow. So S17 had no position update, and the real time clock and calibration were also incorrect. Yet, S17 was reported by a number of stations. Initially on 20m only, by only two stations. The hypothesis is that the real time clock was off, so it was transmitting at incorrect timing, but close enough that a couple of receiving stations whose timing is also off, could copy it. As the day went on, S17 got more reports also on 30m. So probably the un-GPS-disciplined real time clock was drifting into correct timing. It was good luck that the random start time of the system was such that it was close enough for WSPR decodes. The telemetry therefore contains temperature and battery information but nothing on position, altitude or ground speed, all of which come from the GPS.
Apparently S17 survived the storm yesterday, and lived through to the following morning. It woke up when the sunlight allowed the solar cells to charge the battery. S17 made excellent progress East across the Atlantic, reaching ground speeds of 110 knots (204 kph, or 127 mph). It also climbed altitude, reaching a peak of 11,560m.
The same thing happened near the end of the day, the GPS stopped reporting and the temperature appeared to rise. Hopefully this does not mean any problem exists, hopefully it is just something which happens as the battery voltage drops.
Dave VE3KCL had a successful launch of S17 (see photos below) at dawn local time on 19-Sep-2016. S17 climbed to a little over 10,000m and it was a great relief to see the SIM28C GPS module still operating over 10,000m, following earlier flights in which the GPS shut down at 10,000m. For this flight Dave doesn't do a hardware reset of the SIM28C every transmit cycle, which for some reason appeared to force the module back into the lower altitude mode.
S17 headed East, and right into a big storm near sunset... there were some big altitude fluctuations, then the GPS stopped reporting. The transmitter continued sending reports for another 1 hour but without location or altitude. The temperature kept going up, which was really making us nervous - since higher temperature can often mean lower altitude, i.e. the balloon is coming down. So, the balloon went to sleep with unknown position, heading into a big storm, perhaps coming down... and very uncertain, would it still be flying when the morning light came...
This flight uses two hydrogen-filled "party" balloons with 4.5g of free lift. The balloons were NOT pre-stretched before launch because it seems that might cause fractures in the metal foil which increase leaks and shorten the flight.
The Si5351A Synth, SIM28 GPS and regulator are integrated now onto a PCB that Dave designed. There is also a PA transistor, to boost the power output a little. See the measurements table below for more info on the power output at different battery voltages.
The callsign is "VE3KCL" and the balloon telemetry channel is 4 (see S-4 page for more details).
Note the infra-red camera photos, showing most of the heat being generated by the Si5351A chip itself.