Monday, April 18, 2011

KJ6KUV-11 flight and successful recovery!

KJ6KUV-11 was launched yesterday from Ojai, California at 0820 PDT and successfully recovered 84 minutes later near Oak Park, 53.6 Km to the south-east! Check Kyle's blog for details, but I think all the efforts can be summarized with one single picture:


During the whole flight, the balloon was able to steadily report its position via APRS and the trajectory could be followed at Between 12-16 Km altitude, the balloon caught the jet stream and sped up quite a lot as you can tell by the more spread-out points on the map!

kj6kuv-11 trajectory

The tracker was a Trackuino board with a Venus 634FLPx GPS and a Radiometrix HX1 300 mW radio transmitter. We were not sure the HX1 was going to deliver enough power to reach any digipeater from that high up. Well, sure it did... At its peak altitude (20 Km), the signal could be heard from Phoenix, Arizona, which is... 597 Km away!

kj6kuv-11 hx1 range

We were also not sure the Venus 634FLPx would report its position above 18 Km high, since many manufacturers seem to get the CoCom limits all wrong. But then again, the above picture proves how the GPS worked perfectly at 20036 meters.

Here are some flight stats I gathered with WBALTRAK. This is a plot of altitude versus time:

kj6kuv-11 altitude vs time

The ascent rate was smooth and constant at about 500 meters/minute. After the balloon popped, the payload fell at a vertiginous 1000 meters/min and steadily slowed down as the air density allowed the parachute to deploy. The payload landed smoothly at 294 meters/min:

kj6kuv-11 vertical rates

The speed was about 38 Km/h average and it reached peaks of 100 Km/h (about 60 mph) while the balloon was caught by the jet stream:

kj6kuv-11 speed

This was a lot of fun to track :)


Saturday, April 9, 2011

First Flight

I'm really excited to announce that Kyle (KJ6KUV), a great contributor to this project, is launching a balloon and he'll be using a Trackuino board to track its payload. He'll be launching from the Oxnard airport (California) on sunday april 17 around 8:00 am pacific time.

To track the balloon online go to this page. It will have the most recent position as well as the previous positions reported:

Best of luck with the chase!

4 things

A few random updates:

1. I'll be giving a speed talk on Trackuino, high altitude balloons and near space photography at OSHWCON 2011! Quoting their web site:

The Open Source Hardware, Electronics and Robotics Convention is a 3-day event organized by the Synusia collective in an effort to extend the Open Source Software and to promote electronics and the philosophy of "do it yourself". The event will take place in Madrid at the Centro de Formación Padre Piquer,  from the 23 to 25 September 2011.

2. This blog is becoming a bit chaotic, with bits of information here and there. So, I'm giving the Trackuino project's site a facelift. From now on, technical articles will go to the wiki, while news and event updates will stay in this blog.

3. Even though the wiki is pretty much empty right now, I just posted an article on flight prediction based on Rick von Glahn (NØKKZ) great WBALTRAK software. Unlike on-line prediction sites, this program uses actual inflight data to predict the touchdown point with higher accuracy. Check it out, I think flight prediction is a key step prior to and during the flight of high altitude balloons!

4. Last, but not least, we're having our first Trackuino flight next sunday! But this deserves a dedicated post, so stay tuned!