High Altitude Balloon Flights Carrying HF Radio Telemetry
Balloon flight BB10 - launched on 07 June 2020 at 20:38 UTC
A test flight of a triangular pyramid solar cell arrangement designed to capture the sun's energy and power the tracker transmitter from sun rise until sun set. Further information and photos of the harware are at the bottom of this page. Thanks to a generous sponsor, BB10 is flying under an SBS-12 balloon at an altitude between 11,500m and 13,300m ASL depending upon the atmospheric pressure on the day and the heat absorbed from the sun. Refer to these links for the latest flight information ...
Tracking on Habhub (temperature may be incorrect)
Tracking on APRS
NOAA path prediction (the last prediction)
Flight comments:
06 October 2020 - Nothing heard from BB10 since the last decode over 4 days ago. According to the NOAA trajectory, the balloon's location during that time should not have presented any propagation difficulties, therefore we must assume the balloon is down.
It was an interesting flight of just over 115 days which achieved 10 circumnavigations of the earth, and illustrated the power advantage of the experimental triangular pyramid array of solar cells that could run the transmitter from a few minutes after sun rise to a few minutes before sun set every day without a battery or super capacitor.
There are more photos and details of the payload transmitter at the bottom of this page.
01 October 2020, 13:44 UTC - The last spot from BB10. No trace of either the WSPR or JT9 signals from BB10 on 02 October despite good signals from the PS-80 balloon in the same general region (southern South America). We'll keep monitoring for a few days, but the prospects are not good.
29 September 2020, 05:24 UTC - After many weeks (16) of steady and rapid progress eastward almost everyday, the BB10 flight path appears to be changing with the seasons and becoming more eratic. Refer to the NOAA path prediction link above.
28 September 2020, 00:54 UTC - BB10 has completed its 10th circumnavigation of the world
23 September 2020, 17:14 UTC - Back into fairly clear skys and entering a stretch of faster jetstream again.
19 September 2020, 19:54 UTC - The 20m band propagation is changing with the seasons. An improvement was anticipated with the approaching equinox, but it seems not to be the case and decodes from the 10mW to 20mW telemetry transmitters on the various 'pico-balloons' flying at the moment (including BB10) are harder to come by.
The NOAA path prediction has BB10 flying across southern Brazil and meeting with some high altitude 'weather' according to windy.com, with cloud tops extending to the high 12,000m altitude ranges. The next few days "could be interesting" in terms of balloon survival.
16 September 2020, 18:34 UTC - BB10 'woke up' 450km east of the launch meridian thus completing its 9th circumnavigation of the world
11 September 2020, 14:18 UTC - BB10 appears to have entered a fresh section of jet stream and re-gained the speeds we have become used to. This may not last as the southern hemisphere summer approaches and potentially alters the flow of the jet stream ... to be seen if BB10 remains aloft a while longer.
Green circle = area of slow jet stream over southern Africa where BB10 was stuck for two days without propagation
Red circle = last position at 14:18 UTC near Madagascar, entering the faster jet stream flow again.
11 September 2020, 11:00 UTC - Finally some weak signals from about 09 UTC, so the 'problem' was simply lack of propagation on 20m for the first time since launching BB10 95 days ago.
10 September 2020, 13:40 UTC - Very little was decoded at all on 20m WSPR or JT9 from BB10 yesterday, and nothing at all today.
The NOAA Hysplit trajectory prediction has had BB10 very slowly crossing Namibia, Botswana and Zimbabwe for the last few days, so maybe the balloon is in the 'skip zone' for radio signals to the ZS stations who have been diligently providing tracking from that side of the world ...
... or the balloon is down? Satellite imagery over the area for the past 2 days has shown clear skys, so if the balloon has come down, it was not a weather related event.
A screen shot of the last good NOAA prediction is shown below and indicates that BB10 may be in the 'skip zone' for ZS until 12 September. Nothing to do but continue monitoring for the coming days ...
02 September 2020, 03:44 UTC - BB10 has completed its 8th circumnavigation of the world.
23 August 2020, 19:00 UTC - BB10 is now well to the east of New Zealand and has completed its 7th circumnavigation of the world.
23 August 2020, 06:18 UTC - BB10 just went into darkness a few hundred km short of completing it's 7th lap around the world. The balloon is in an area of very fast Jet Stream and travelling east at about 230km/hr, so it should cross the launch longitude in about 2 or 3 hours time ... however, we will have to wait until the transmissions resume just after sunrise at about 18 UTC for confirmation.
19 August 2020, 14:26 UTC - SE of South Africa and heading east across the Indian Ocean towards Australia.
18 August 2020, 16:00 UTC - The balloon is now just south of South Africa.
16 August 2020, 21:00 UTC - BB10 crossed central Uruguay and the southern tip of Brazil today, and was just over the Atlantic Ocean by nightfall. The predicted track has the balloon near South Africa in 2 days time.
15 August 2020, 22:14 UTC - BB10 is still in the Pacific Ocean just west of Chile but should cross South America tomorrow.
14 August 2020, 23:14 UTC - The balloon travelled mainly NNE today and is still in the Pacific Ocean about 1000km west of Chile. Slower progress is predicted for the next couple of days.
13 August 2020, 19:00 UTC - The trajectory for BB10 has moved south to be about 60 degrees south latitude today. The temperature is very cold and the sun angle is low (maximum sun elevation at midday will be about 19 degrees), however the triangular pyramid array of solar cells continues to run the tracker transmitter from sunrise until sunset.
12 August 2020, 20:44 UTC - The short distance 20m band propagation finally opened about 2 hours after sunrise and we can confirm that BB10 has completed the 6th circumnavigation of the world. The balloon is currently at locator AE24hw near the Chatham Islands about 800km SE of Wellington, New Zealand.
12 August 2020, 06:04 UTC - BB10 should cross the start-line longitude overnight and complete lap 6 of the earth.
10 August 2020, 09:14 UTC - Today BB10 has been 9 weeks in the air.
09 August 2020, 02:14 UTC - BB10 is now about 3000km SE of Madagascar on its way across the Indian Ocean towards Australia.
07 August 2020, 07:14 UTC - Back into the faster jet stream again and travelling east at around 120km/hr. BB10 is now about 1200km SW of Cape Town, South Africa.
06 August 2020, 18:00 UTC - The balloon is in an area of slower jet stream speed for the last day or so. BB10 is presently located at about 3000km WSW of Cape Town, South Africa.
04 August 2020, 20:00 UTC - BB10 is now flying over the South Atlantic Ocean.
03 August 2020, 19:04 UTC - BB10 is presently located about 1500km west of the southern Chilean coast and should cross South America during the next 24 hours.
02 August 2020, 19:14 UTC - Now BB10 is just over half way across the South Pacific Ocean.
01 August 2020, 20:14 UTC - BB10 completed the 5th circumnavigation of the world overnight and is now 2000km east of the launch longitude and about 3000km SE of New Zealand.
31 July 2020, 21:34 UTC - BB10 is now SE of Tasmania, Australia and flying SE past an area of very bad weather. It should stay away from the worst of the storm and cross the launch longitude tonight to complete the 5th lap of the world.
31 July 2020, 00:00 UTC - BB10 'woke up' a few minutes ago about 900km SSW of Perth, Australia.
28 - 30 July 2020 - Fast progress across the South Atlantic and Indian Oceans.
27 July 2020, 10:54 UTC - BB10 has crossed South America and is now over the South Atlantic Ocean.
25 July 2020, 19:34 UTC - BB10 is now just over half way across the South Pacific Ocean. Tracking updates have been a bit sporadic for the last few days because I have not had my receiver running here. This is due to the Beverage antenna being removed to allow our cattle to graze in the eastern paddock. The WSPR decodes from the current very remote corner of the earth have been patchy from other stations.
22 July 2020, 19:54 UTC - BB10 'woke up' 76km east of the launch longitude and has completed the 4th circumnavigation of the world just north of Wellington, New Zealand.
21 July 2020, 22:04 UTC - Presently south of Tasmania, Australia.
21 July 2020, 00:34 UTC - Presently south of Perth, Australia.
16 July 2020 - Crossed South America, and now over the South Atlantic Ocean.
15 July 2020 - BB10 completed the trip across the South Pacific Ocean and is currently over Chile.
12 July 2020, 16:56 UTC - The second half of the WSPR telemetry was received by KA7OEI and showed that BB10 was still flying at 12320m ASL. Since 19:14 UTC propagation allowed the full telemetry to be decoded and confirmed that the balloon was already half way across the South Pacific Ocean towards South America.
11 July 2020, 18:34 UTC - The first transmission from BB10 today was at locator AF49pq about 1500km ENE of the launching point. The flight has completed its third circumnavigation of the earth.
10 July 2020, 21:00 UTC - The balloon's location is now over the Tasman Sea between Australia and New Zealand. This area was in the 'skip zone' for all receiving stations first thing this morning and, as a result, no updates were received until well after BB10 started transmitting. Now stations near Adelaide, Australia are receiving the balloon's transmissions and this will spread to other areas once the MUF increases and the ionosphere can support high angle signals. The balloon is over another area of high surface pressure (anticyclone), so we have high altitude again.
We are hopeful that BB10 will cross the longitude line of the launch point tonight and the flight will then have completed its third circumnavigation of the earth.
09 July 2020, 20:44 UTC - BB10 'woke up' near the WA/SA border of Australia (locator PF38ms) travelling at about 150kmph towards the east.
09 July 2020, 00:24 UTC - BB10 is about 800km WSW of Perth and in the center of a large anti-cyclone with surface pressure of 1030mb, hence the higher altitude today. Just after sunrise the altitude was 12640m and will probably rise higher has the sun warms the balloon.
08 July 2020, 01:54 UTC - Start up today at locator NF15QM about 3000km WSW of Perth, Australia. The speed has reduced to around 80 kmph and the altitude has increased to 12,400m ASL. windy.com indicates the surface pressure in the area is 1020mb and that BB10 is flying towards an anticyclone with surface pressure around 1031mb, so lets see if the altitude rises further in the coming day or two.
07 July 2020, 04:54 UTC - BB10 'woke up' at grid locator LE62mw (south of Madagascar) and is tracking ENE at nearly 200 kmph.
06 July 2020 - a high speed day south of South Africa travelling ESE at around 230 kmph.
The anticipated 'wake up' tomorrow (06 July at 07:30 UTC) is about 2000km WSW of Cape Town, South Africa. The trajectory prediction has the balloon flying straight into a deep depression about 1500km south of Cape Town by sunset, so it could be 'an interesting day'. We expect the altitude to drop considerably, but fortunately windy.com is not predicting any high cloud.
05 July 2020, 18:23 UTC - Shut down about 3000km east of Buenos Aires with about 1.5 degrees of sun angle remaining before sunset. Today BB10 reached speeds up to 180 kmph in the jet stream.
05 July 2020, 10:44 UTC - BB10 'woke up' over the South Atlantic Ocean about 1800km ESE of Buenos Aires, Argentina.
04 July 2020, 20:42 UTC - BB10 crossed South America today and is about to catch a high speed jet stream across the South Atlantic and Indian Oceans taking it half way around the world to Australia over the next 4 to 5 days.
02/03 July 2020 - Slow and uneventful progress SW of South America. More updates in a few days ...
01 July 2020, 20:03 UTC - BB10 stopped with 1.3 degrees of sun remaining at locator DD72nw. The next 'wake up' is anticipated on 02 July just after 15 UTC.
01 July 2020, 18:00 UTC - The altitude has increased to 11,900m ASL again, but the surface pressure at the BB10 location according to windy.com remains at 996mb and the temperature is somewhat lower. This leads to the conclusion that the balloon cannot have lost gas and the likely cause of the altitude drop was a little bit of extra weight (ice?) on the payload , and that has now somehow gone.
30 June 2020, 22:46 UTC - 'Gone to sleep' at DD45op with 1.6 degrees of sun remaining.
The NOAA trajectory prediction has changed again, this time quite significantly when compared to the screen shot below. It now seems that BB10 will not move south to Antarctica and into permanent darkness for 2 or 3 days.
30 June 2020, 21:00 UTC - Again BB10 started up at an undetermined time due to geographic isolation in the South Pacific Ocean and a lack of 20m band propagation. The first transmission captured was a lonely WSPR spot by K1RA 10,600km away at 17:04 UTC ... that was over an hour past the sunrise time at the DD47 location.
30 June 2020, 00:13 UTC - The first 2 or 3 hours of today's transmissions (29 June) were missed due to isolation in the middle of the South Pacific Ocean. BB10 shut down at 00:13 UTC while located at CE83ub with 1.5 degrees of sun angle remaining.
The altitude has dropped again, it is now around 11,600m ASL. The surface pressure in the area is 996mb which is lower than that at the launch date (1022mb and 12,300m altitude). There are a large number of low pressure systems in the southern latitudes (it is winter in the southern hemisphere, so no surprises there), therefore we don't expect the altitude to recover unless BB10 moves into one of the few high pressure systems. It is also possible that the balloon and/or payload has collected a few grams of ice particles, or the balloon envelope has leaked some hydrogen gas. Both occurances would of course reduce the float altitude.
29 June 2020, 00:58 UTC - BB10 shut down with 1.3 degrees of sun angle left.
The NOAA trajectory prediction for the next 7 days suggests that we might see 2 or 3 days more tracking, then 3 or 4 days too far south with no sun, and then the next signals could be from the South Atlantic Ocean on 05 July.
28 June 2020, 19:54 UTC - BB10 'woke up' more or less according to the time and location of the NOAA Hysplit preditction of two days ago. The balloon was located at BD30if and has completed its second circumnavigation of the earth.
27 June 2020, 05:02 UTC - BB10 'woke up just before 01 UTC and lost the sun at 05:02 UTC with 1.7 degrees of sun angle remaining.
Tomorrow BB10 will be >70 degrees south latitude where there is no sun above the horizon, so the next 'wake up' is expected on 28 June somewhere SE of New Zealand at about 19:30 UTC.
26 June 2020, 08:12 UTC - BB10 lost the sun at 1.2 degrees of sun angle. The next 'wake up' is expected on 27 June at about 01 UTC. The NOAA hysplit trajectory prediction shows that BB10 might run for about 4 hours tomorrow, then disappear for two days due to no sun because the flight track takes the balloon lower than 65 degrees South latitude.
25 June 2020 - The anticipated 'wake up' was at about 02:40 UTC on 25 June about 3000km south west of Perth, Australia. The actual wake up time of 03:24 UTC was a bit later than expected because the trajectory had changed and BB10 was several degrees of latitude further south than predicted. There are not many day light hours down there at this time of year (southern hemisphere winter), so BB10 only ran for about 6.5 hours today and shut down at locator ND54bs around 09:18 UTC with 1 degree of sun angle left before sunset.
The cold winter at the deep southern latitude is keeping the temperature data from BB10 on the cold side of the "value wrap-around" point, so I have made a change to the telemetry decode calculation so it displays correctly on Habhub (at least while the temperature is below -20 Celcius).
23 June 2020, 14:00 UTC - BB10 'woke up' at 07:14 UTC with about 2.5 degrees of sun elevation and thanks to WSPR mode decodes received from ZS1ABU, ZR1AOC, ZS1C, ZS1OK, ZS4TX, ZS6KN (and ZS6KN/1), ZS6VOL, DP0GVN-1, and PY2GN the balloon flight was tracked for almost 7 hours until it stopped at 14:00 UTC with 1.3 degrees of sun angle remaining.
The next anticipated 'wake up' is at about 04:30 UTC on 24 June about 3000km south east of South Africa. At midday (around 07:30 UTC) BB10 will be located at about 54 south latitude and the maximum sun angle will be just 12.6 degrees. With the previous 'flat' solar cell arrangements there would not be enough solar energy to start the transmitter, but we expect that the pyramid solar cell arrangement on BB10 will power the tracker transmitter for about 5 hours.
22 June 2020, 17:02 UTC - BB10 continued to track across the southern Atlantic Ocean and 'went to sleep' about 3500km SW of Cape Town, South Africa with 1.8 degrees of sun elevation remaining before sunset. The next anticipated 'wake up' is at about 07:00 UTC on 23 June at about 2000km south of Cape Town.
21 June 2020, 18:54 UTC - BB10 shut down during this standard WSPR transmission with the sun at 1.4 degrees above the horizon.
There could be an extreme test for the pyramid solar cell array in a few days as the NOAA hysplit trajectory predictions shows BB10 will move towards the South Pole. Presently the highest sun angle at 65 degrees south latitude is 1.5 degrees which might be enough to start BB10 up at midday (local balloon time) for a position update, but BB10 is predicted to go further south than that. There are interesting times ahead if BB10 remains aloft!
21 June 2020, 11:46 UTC - The first transmission received was the WSPR telemetry frame, but the standard WSPR must have been transmitted 2 minutes earlier so, allowing for a GPS cold start, BB10 'woke up' a couple of minutes before 11:44 UTC with the sun at about 1.2 degrees above the horizon.
19 and 20 June 2020 - a 'rinse and repeat' of the previous day regarding no propagation from the southern latitudes at the start up just after sunrise. Transmissions stopped at 1.2 degrees around 23:26 UTC on June 19, and at 1.3 degrees around 21:18 UTC on June 20. Unfortunately the tracking upload 'froze' at about 15:30 UTC ... the location at sunset (21:18 UTC) was FE14go, just off the coast of southern Chile. At the next expected start up (11:30 - 12 UTC on 21 June) BB10 should have crossed South America and be over the south Atlantic Ocean.
June 20/21 is Winter solstice in the southern hemisphere ... the lowest sun angles and the best test for the pyramid solar cell array on BB10.
18 - 19 June 2020 - The start up time and sun elevation could not be determined today because there was no propagation from the balloon's location on 20m at the time. Shut down was at locator BE80pu around 01:22 UTC with 1.2 degrees of sun angle remaining.
18 June 2020, 02:58 UTC - Shut down this evening at locator AD50ov with 1.6 degrees of sun remaining.
17 June 2020, 20:04 UTC - The first transmission from BB10 was at locator AE11 when the sun angle was 1.9 degrees. Yes, it has successfully completed a circumnavigation of the earth!
17 June 2020, 05:02 UTC - The transmissions have just stopped with the sun at 1.2 degrees above the horizon. BB10 was then located at RE46kn about 400km west of the longitude line of the launch position and will make it's first lap around the world in 4 or 5 hours time. BB10 should 'wake up' next at around 20:00 UTC and be located about 1,000km SE of Christchurch, New Zealand.
16 June 2020, 22:00 UTC - BB10 is transmitting, but located in the skip zone for ZL and VK at the moment.
16 June 2020, 06:59 UTC - BB10 shut down at locator QF10ge with 1.2 degrees of sun remaining. The anticipated wake up time will be 16 June at about 20:30 UTC around 1000km W of Wellington, New Zealand.
15 June 2020, 23:14 UTC - The first decode of the day at 2.2 degrees of sun angle. Locator PE47wd.
15 June 2020, 09:26 UTC - BB10 shut down at locator NE93 with about 1.4 degrees of sun remaining. The anticipated wake up time will be 15 June at about 23:30 UTC around 1500km SW of Adelaide, Australia.
15 June 2020, 02:04 UTC - The first decode of the day at about 2 degrees of sun angle. Locator NE27xr.
14 June 2020, 12:38 UTC - BB10 shut down at locator LF91lt with 1.1 degrees of sun remaining. The anticipated wake up time will be 15 June at about 02 UTC around 4000km WSW of Perth, Australia.
14 June 2020, 05:30 UTC - Nice propagation of the JT9 signal on 20m today, even as far as my home station here in ZL during the propagation peak at around 05 to 06 UTC:
0538 -23 -0.0 1705 @ ZL1RS LF21HL ZL1RS1
0538 -2 -0.1 1704 @ ZL1RS LF21HL ZS4TX
0538 -19 -0.4 1701 @ ZL1RS LF21HL ZS6KN
0539 -21 -0.0 1706 @ ALT 12551.M ZL1RS1
0539 -1 -0.1 1705 @ ALT 12551.M ZS4TX
0539 -20 -0.1 1702 @ ALT 12551.M ZS6KN
BB10 is entering another area of low atmospheric pressure on the trip across the southern Indian Ocean between South Africa and Australia, so we expect the altitude to drop several hundred meters during the coming days.
14 June 2020, 04:44 UTC - BB10 woke up 'on schedule' at LF11hq with about 2.4 degrees of sun elevation after sunrise.
13 June 2020, 15:08 UTC - BB10 shut down at locator KF15sr with 0.9 degrees of sun remaining. Today BB10 passed directly over Cape Town, South Africa and was received by many ZS stations with strong line-of-sight WSPR and JT9 signals as high as +20dB SNR. The anticipated wake up time will be 14 June at about 05 UTC around 1000km SE of South Africa.
13 June 2020, 06:24 UTC - The first decode at around 1.7 degrees after sunrise. There was a brief burst of WSPR 10 minutes earlier which might have been BB10 ... the sun's elevation at that time was 0 degrees, right on sunrise. The location now is JF66, about 400km WNW of Cape Town, South Africa and heading directly towards the city. There should be strong line-of-sight 20m band WSPR and JT9 signals into ZS1 at about 09 UTC.
12 June 2020, 16:40 UTC - BB10 shut down at locator JF04ko with 0.9 degrees of sun remaining.
12 June 2020, 08:24 UTC - The first decode at around 2 degrees after sunrise. The altitude is nearly 12,900m and clearly influenced by the higher air pressure at the present location.
11 June 2020, 18:39 UTC - BB10 shut down at locator HF43ub with 0.9 degrees of sun remaining. The altitude improved further as the balloon tracked over an area of increasing surface pressure. From the last JT9 telemetry, the altitude at shut down was 12,728m. The expected wake up time will be 12 June at about 08 UTC.
Muchas gracias a todos los rastreadores de globos LU en 20m WSPR!
11 June 2020, 10:24 UTC - The first decode for the day at about 3 degrees of sun elevation. Tracking according to the prediction below. The altitude has recovered to near 12,600m as it was on the first day ... the surface pressure in the present area (1018mb) is similar to that when BB10 was launched (1022mb), and much higher than it was for the past few days when the altitude was 400 to 600m lower.
10 June 2020, 20:26 UTC - BB10 shut down at locator FE97en with 1.2 degrees of sun elevation remaining. Expected wake up time 11 June at about 10 UTC.
10 June 2020, 12:52 UTC - the first transmission was receved at FE34bx 2 degrees after sunrise. Now flying over southern South America. The altitude has largely recovered to be around 12,300m but there are significant altitude variations (+- >100m) due to 'pressure waves' (turbulence) on the lee side of the Andes mountain range.
09 June 2020, 22:38 UTC - BB10 shut down just now at locator DD88ox with 0.7 degrees of sun elevation before sunset. Hopefully BB10 will start up again on 10 June at about 12:30 UTC somewhere near the coast line of southern Peru.
09 June 2020, 17:04 UTC - the first transmission was received about 1 hour after sunrise with the sun at 6.7 degrees elevation. Not sure if this was the first transmission for the day, or were there earlier transmissions but no 20m band propagation? (consider a 20mW signal, located at 52 degrees south latitude, at sunrise in mid-winter, and 6000km from the nearest RX station). The balloon's altitude has dopped again and is now floating at around 12,000m. This is a concern, but is more or less in line with the NOAA hysplit prediction due to lower air pressure in this region.
09 June 2020, 02:07 UTC - BB10 shut down near sunset at locator BE67xn with 1 degree of sun elevation remaining. It has moved into an area of low pressure resulting in a lower float altitude at around 12,200m.
08 June 2020, 17:26 UTC - the first transmission received after sunrise (a weak decode of the WSPR telemetry by KB5OXR). For this to happen there must have been sufficient sun for a GPS cold start at the latest time of 17:22 UTC. The sun angle at that time for locator BF44am was 0.8 degrees.
08 June 2020, 04:14 UTC - the last transmission for the day with the sun angle at about 1 degree above the horizon ... solar cells only, no battery.
08 June 2020, 00:00 UTC - BB10 reached 'float altitude' about 1 hour ago. The float altitude at around 12600m is slightly lower than that calculated by the float1b spreadsheet (12900m), but the balloon volume used in the spreadsheet was a 'calculated guess' rather than an actual measured value.
07 June 2020, 20:38 UTC - Launched in near perfect conditions. BB10 will test a unique solar cell configuration ... see the photos below. This 3-sided pyramid captures sufficient solar energy on one or more sets of solar cells to power the tracker transmitter at any time between sunrise and sunset (subject to atmospheric clarity at low sun angles). This will typically extend the balloon's transmission time by between 2 and 3 hours each day, and also potentially allow transmissions at the very low sun angles during winter and as are found near the earth's north and south poles.
Temperature:
The temperature displayed on habhub is usually fairly accurate, but at about -20C there is some sort of 'value wrap around' in the transmitted data which causes a blatent error depending on the 'fix' I have running at the time ...
 or
This is due to a different voltage reference used on BB10 than what the transmitter's firmware expects, and a voltage divider on the output of the temperature sensor which didn't work as planned (and couldn't be fully tested because our freezer only goes to -16C). I have two instances of the telemetry script with different temperature calculations to get around this, but don't always have the appropriate one running. However, depending on what appears on habhub, the correct temperature can be determined by either:
Adding 80 to any obviously too low value ... for example: -97.9 + 80 = -17.9C
Subtracting 90 from any obviously too high value ... for example 65.1 - 90 = -24.9
BB10 over-view:
Balloon: a SBS-12 balloon inflated with hydrogen gas providing 7.5 grams of free lift over the total payload weight
Payload: a QRP-Labs U3S based TX sending WSPR mode tracking and JT9 mode plain text information at 20mW on the 20m band
Antenna: a halfwave dipole (0.1mm dia wire) supported on 4 pound fishing braid, with the transmitter suspended at the feed point
GPS: ATGM336H with a reset system the same as on BB08 and BB09
GPS antenna: a 1575 MHz dipole made from 0.15mm diameter enamelled copper wire
Solar cells: a triangular pyramid arrangement of 39mm x 19mm 0.12W solar cells set up as 3 banks of 4 cells 120 degrees apart
The 3 banks of cells are each inclined at about 60 degrees above the horizon and generate up to 2.7V when facing the sun
Each bank of 4 cells is fed via schottkey isolation diodes to provide up to 2.4V at the boost regulator input
Voltage regulator: a CE021 'charge pump' boost regulator with 3.3V output (see photos below)
Total payload weight: transmitter (1.6 grams) + regulator (0.5 grams) + solar cells (7.1 grams) + antenna (1.0 grams) = 10.2 grams
Balloon lift: 17.7 grams of neck lift less the 10.2 grams of payload = 7.5 grams of free lift
Anticipated 'float altitude': 12,900m (subject to external conditions like temperature and air pressure)
BB10 transmitter compliment:
Processor: ATmega328P-AU
Processor clock: 8MHz
Synthesiser: Si5351a
Synth reference: 27MHz TCXO
Built on a 'full' SA6BSS PCB complete with solar voltage ("battery") and temperature sensors
Insulation: none
Transmitter frequency:
The WSPR and JT9 signals can be received with a SSB receiver in USB mode tuned to the standard 20m band WSPR 'dial frequency' of 14.095600 MHz. The WSPR signal appears on the waterfall in the upper half of the WSPR band slot at about 1565Hz, and the JT9 appears at about 1700Hz (see the screen shot in the pictures below).
Transmitter schedule:
The JT9 messages and GPS reset timing have been rearranged to fill up the 10 minute transmission 'frame'. The altitude is sent once in the WSPR telemetry and twice via JT9 for regular height information. There is no battery, so the transmitter only works during the day time. Here are the transmission timings:
MinuteTransmission
:x4Standard WSPR mode ... callsign ZL1RS, grid locator as determined by the GPS, power 13dBm (20mW / 0.02W)
:x6Special WSPR mode balloon telemetry (channel 02)
:x8JT9 using message 00 with QRP-Labs U3S tags #CS and #M6 - ZL1RS + the current 6 character Maidenhead locator
:x9JT9 using message 01 with plain text and QRP-Labs U3S tag #AT - ALT #ATM - (altitude in meters)
:x0JT9 using message 02 with plain text and QRP-Labs U3S tag #GS - KNOTS #GS - (speed in knots)
:x1JT9 using message 03 with plain text and QRP-Labs U3S tag #GC - BEARING #GC - (course in degrees true)
:x2JT9 using message 04 with plain text and QRP-Labs U3S tags #A0 and #A3 - TMP#A0 SOL#A3 - (see below)
:x3JT9 using message 01 with plain text and QRP-Labs U3S tag #AT - ALT #ATM - (altitude in meters)
:x3 + 52sCW using message 05 - the letter "E" in Morse Code ('reset' - see BB08 flight for the experimental GPS reset information)
#AT, #GS and #GC are altitude, ground speed and ground course from the GPS output strings
#A0 is the raw A-D value from the temperature sensor, and #A3 is the raw A-D value of the solar cell output
Decoding and tracking:
The WSPR telemetry capture, decoding and forwarding is done by a version of Aaron M7REG's python script (forked from SM3ULC) with further modifications by Andy VK3YT and myself. Thanks also to Jim N2NXZ for the set-up tips that saved a lot of potential grief.
The PCB is the same as BB08 and BB09 as pictured above. To be added in 'dead bug' style are a few SMD components for the battery and temperature sensing. The programming header to the right hand side is cut off before the flight
The pyramid solar array
The tracker transmitter board and regulator board with schottkey isolation diodes mounted inside the solar pyramid. The GPS wire dipole is extended beyond the solar cells to the right on a twisted pair feedline.
BB10 with triangulation braces added to the pyramid base. Here it is undergoing a leveling/balancing test before soldering on the antenna wires. The wires protruding at the lower left are the GPS dipole.
To give an appreciation of the overall size ... each of the three solar panels (4 cells) is smaller than the size of a credit card, and the whole structure (solar cells, polystyrene frame, and transmitter) weighs 10.2 grams which is less than the weight of 2 credit cards. The pyramid can sit comfortably on the palm of one's hand.
Screen shot of the waterfall showing the WSPR and JT9 trails with their associated decodes. The 'reset tone' (morse code letter E) is sent after minute :x3 (02:53) and is just visible as a very faint line extending to the left at the end of the last of the JT9 tones.
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