My first Nightsonde

NP1 Essen – Birnbaum
Vaisala RS41-SGP / P3530031 / 22.01.2019 0000Z
πŸ”— public transport

After the last Essen sondes had not made it to a position uncomplicated to reach, P3530031 broke through this series. The prediction was at first southeast of my QTH, between Wiehl and WaldbrΓΆl, but thanks to the early burst below 25000 m the landing shifted some kilometers to the north. Despite the low descent rate the probe didn’t fly as far as I expected and landed northwest of me in the Gelpetal in a forest. So far the nearest landing site to my my QTH since I’m into radiosondes with 6.62 km as the crow flies (in 2017 two landed within sight of my window, but I didn’t knew anything about them…)

A friend, who lives a little over a kilometre from the landing site, had asked me to let him know when I would be hunting in the vicinity of his house. I wrote him at night and we arranged to meet in the morning. The first bus would arrive there at 8:10, I hoped that the probe’s batteries would do that despite the cold weather.

Arriving on site, the fact that only 400 m away from the sonde the signal level was sufficient for decoding, made me hope for a ground landing in the forest. So it was, probe lying on the ground, parachute and big balloon remainings approx. 20 m further in the tree. Unfortunately the balloon remainings could not be abseiled. The large remainings of the balloon could also mean that the balloon did not burst completely, but leaked helium bit by bit. The probe shows traces of corrosion on the broken sensor arm, which surprises me after only one night in the forest.

No Radio neccessary

#9 Meppen – Radevormwald
Vaisala RS41-SGP / N2130183 / 02.01.2019 1100Z
πŸ”— individual transport

For the first Meppen sondes of the new year, the prediction showed a landing almost at my front door. The wind was and is very extreme at the moment, sondes fly to places where one would hardly expect them. Unfortunately all three sondes on 02.01. scattered quite strongly. The first sonde had a burst under 17 km and fell very fast, but landed exactly at the prediction, which was for a working parachute and average burst altitude. The morning sonde had an excellent parachute and flew almost 150 km further south. The midday probe finally seemed to land well for me, but descendet faster than I thought and only made it to Radevormwald.

So I discussed the strategy with flynamic, who was exceptionally not in Bonn at university. It was clear that all sondes would land further west the next day. However, Cologne is easier to reach than Radevormwald. But if prediction and probe behaviour were to spread like this again, it would be pure gambling. So it was decided to make a trip to Radevormwald. Jason, who had only taken part in an unsuccessful sonde hunt by now, also had time and came with us.

As usual with car searches I booted my Macbook into Windows a few kilometers before the landing site and opened the toolchain. But the RS41 Tracker had a New Year present for me “This Engineering Version of RS41 Tracker is expired”. I totally forgot. So I downloaded the new version via mobile hotspot, unpacked it and “Your PC is incompatible with this Application”. No simple debugging, to be honest I didn’t feel like debugging at all. We had already narrowed down the landing site to a 100×500 m strip, so DFing was the easiest solution, albeit with the Macbook in hand. (I hadn’t taken the new Baofeng and my attenuators with me to the TH, because I didn’t really expect a hunt, and only packed the Moxon and the RTLSDR).

We looked for a parking place and got the equipment ready. Before we could look around and find out if there was anything to see, a local resident came. We explained our intentions and he had already noticed the landing site about 350 m away at the edge of the forest and showed it to us. Parachute and probe lay on the meadow at the edge of the forest, the string hung on the last tree. The recovery was easy, the unroller not completely unrolled. Third N sonde, second ABS sonde, first BW sonde with intact salvaged parachute. No more meppen style cardboard :cry:.

The sondes on 03. and 04.01. flew to reasonable positions, but I didn’t have time to take the train to Cologne in the morning and since ON-1 is down at the moment, there is no cold search at the weekend. But at least one more launch site in my CV, increasing the number to five so far.