[Metalab] OHM2013 / Wetterballoons?

[Rene.Schickbauer at magnapowertrain.com]

Hi!

> There are several launches of weatherballoons in Austria every day
> (usually twice a day per station). As far as I know every airport is
> doing this ...
>
> PS: don't know about permits to start a balloon, maybe one has to
> contact Austro Control ...

I'm also not sure about the 403MHz frequency band this radiosonde uses. I don't want to disrupt commercially launched weather balloon reception. But i guess, since we most likely will need a permit anyway, that should be ok as well.

I've just contacted the Royal Netherlands Meteorological Institute (Ministry of Infrastructure and the Environment) via their crappy Webform to get some details about the relevant regulations. I guess they should be able to tell me the details, since they are part of the government branch that does all the balloon launches. May take some days before i get the answers...

If we are going to launch one or more balloons anyway (that is, if we get permission), we might as well think about one with a ham radio payload as well. What about a simple, cheap, lightweight "space cam"? Given the location[2], we can assume we'll never recover the payload, has anyone experience with either downlinking photos or videos?

I *might* be able to cheaply get my hands on more of those more or less bio-degradable, no-heavy-metal water activated batteries[1] used in the above mentioned radiosondes or complete radiosondes (including the batteries). 

The newer digital radiosonde are quite expensive (30-40 Euros up), but sometimes you can get the older RS80 models for 5-7 Euros per piece. 

If i understand correctly (which i probably don't after 30 minutes of googling), the RS-80 encodes the sensor readings analog as different tones/frequencies. E.g. the sensors get switched round robin to be part of a flip-flop, which changes the frequency depending on the sensor value. Which in turn is what gets FM-modulated onto the 403MHz carrier. There's also some sort of GPS which doesn't measure absolute but relativ position or something for ground bases calculation of wind speed (this one seems to be modulated onto the carrier through some kind of frequency shift keying, according to some guy who tried to adapt the GPS part of the sonde for something else).

I have the relevant PDF on my office machine, so i can post that tomorrow (if i don't forget).

This stuff will probably take a huge amount of nerve-wracking Ebay bidding, government haggling, radio hacking, software coding, gnu-radio learning and facepalming. But i don't have any other project planned for Ohm2013, so why not open our own MetaLab weather science research station ;-)

LG
Rene

[1] http://en.wikipedia.org/wiki/File:Side-view-water-activated-battery.jpg

[2] "Water to the right of them, water to the left of them, water on top of them, volley'd and thundered. Stormed at with rain and hail, boldly they flew and well, into the jaws of death, into the storm of hell, flew the four hundred(mhz)!" (Adapted from "The Charge of the Light Brigade")