caught 2024-04-05 1am written 2024-04-07 12pm

Finally after a number of failed attempts I have caught a radiosonde.

I had attempted to drive out to a few nearby radiosondes like when V2431368

landed in Wollert near Mill Park - but as it is subrubia it was found, most likely on landing so rocking up 1 hour late was not going to cut it. On last Thursday 4th of April I decided to see if I could still get a signal from that days radiosonde which seemed to land in an industrial estate and or the nearby grass lands it was heading for around Epping V2431234.

As I got into the car I decided to fire up the radio just to make sure it works and what do I hear? the sound of a fresh radiosonde. Sure enough V2430897 is bound to land around Sunbry so if I was luck I could pick both of them up.

I got out to Epping and nothing, just the sound of the currently sounding one heading for Sunbry. I attempted to predict an updated path of where it might fall using predict.sondehub.org launch_altitude=21000 using the launch and coordinates of where the radiosonde was currently sounding 21km up. I got a prediction 9minutes down the road, so I headed there. When I got there I saw where the balloon was and it seemed to be landing back near the airport. Off I drove and arrived at the back of the airport and sure enough, as I corner, right there barely 5 meters from the airport perimmiter fence, on the road is the triangle reflector. I park the car, grab the reflector and follow the string towards some grass and finally a tree. I pull on the string, and too late realise that the radiosonde was likely at my height but I have just pulled it up into a 7 metere gum tree. Luckly it does not get stuck and the little syrofoam box falls to the ground at my feet. I grab it all and stuff it into the back of the car. I switch my radio on and it still receives the familiar signal. I pry the radiosonde appart, pop out one of the Enegrizer lithium batteries and radio silence. I drive home listening to ABC late night quiz, hang the radio sonde in the living room as some kind of a hunting trophy and go to sleep

Next time

So I have started experimenting with some Microcontroller (ESP32) based experiments/in_location_tracking using GPS, Magnetic sensor and OLED display to track direction. Looking at driving and trying to get an update on where the radiosonde is and where it is planning to land I would imagine a system like the following would be beneficial

  • mounting in the car
  • large display that stays on and gives all the relevant data - like an iPad
  • a live decoded radio signal - with coordinates and altitude, say from my computer or in future from a de-tuned LoRa module. In the mean time it could just be fed directly from the https://radiosondy.info/ site?
  • a zoomed in version of the map on the balloon and the predicted land site
  • updates of the land site given current data and maybe looking up the https://predict.sondehub.org site, not sure how it deal with a falling object only? maybe put in current coordinates and say that is the hight of the pop?
  • a clear indication of it is rising and or falling
  • prediction of when it will fall
  • updated prediction of fall based on descent rate and hight
  • updated driving instructions to the location it is predicted to land
  • and given I am trying to brush up on some angular in my other learning blog https://saramic.github.io/learning/ may as well look at that. it will probably just be an extension of my experiments/in_radiosonde_notifier

TODO - image of this dashboard idea!!!