So the plan was for Chris Stubbs to launch on Saturday 18th October and me to launch on Sunday 19th October at Kingston Ridge Scouts Campsite in Essex. Chris was already on site by the time arrived. I was kindly ferried from my home location by Dave Hillwood since I don’t drive and carrying the kit by public transport wasn’t a realistic option. Chris had waited until the day to decide between launching a foil or a latex and he chose a latex due to the conditions. Although the launch was scheduled for 12:30pm, due to last minute schedule changes, we had to launch a little earlier. We eventually launched around 11:00am.
When the time came, one of the Scout leaders summoned the cubs with a few short blasts on the whistle. They assembled around Chris whilst he explained to them what was about to happen. I had filled a test balloon to check the wind direction.
Perhaps I needed more gas!
After I first let a better filled test balloon go to check the wind speed/direction, the cubs were led in a count:
5 – 4 – 3 – 2- 1 – Launch!
Chris seemed unconcerned with the prevailing conditions, and justifiably so since it brightened up later on. JOTA1 made good progress. I manned Peter Sipple’s laptop which was connected to a projector and Mike Lynn’s Yaesu FT-817D and Chris used his RTL Dongle and Laptop.
Due to a hiccup with the mic input on the laptop, we used a USB soundcard dongle to do the job. It worked well and JOTA1’s telemetry was decoded perfectly. Meanwhile, the cubs were once more assembled to release their own balloons carrying tags for their return.
JOTA1 did very well and flew all the way to the coast of The Netherlands with many Cubs, Scouts and Helpers popping into the balloon tent to check the current position on the tracking page.
As you can see from the object movie still, there was a short glitch when JOTA1 restarted and took a while to regain it’s GPS fix. Luckily, it came back and stayed pretty constant for the rest of the flight. We were all really hoping it would make landfall but it didn’t quite make it. Still, a very successful flight and a great taster for everyone at the camp. By the end of the day, conditions were really nice and I hoped that it would be the same on the Sunday for me to launch my foil.
For the rest of that evening, after some dinner ordered from a local takeaway, Chris and I assisted the scouts in building minDUINO kits that I’d got together with the help of RS Components. You will be able to read all about that on my other blog ProjectAVR soon.
I arose early at home the next day to be greeted by cloud and squalls of rain. I wasn’t hopeful for a launch. However, again, Dave Hillwell kindly came and got me and by the time we arrived on site, things were looking up. The clouds were parting and blue sky was visible. Again, Chris was already on site and we set about setting up the receiving station, this time in another tent, and devouring rather nice Bacon Rolls prepared by the Scouts for breakfast.
The idea with JOTA2 was to get it to ‘Float’. This is when the balloon ascends until it reaches the point of buoyancy where the balloon doesn’t burst or leak. This enables it to ‘Float’ for a long distance as demonstrated by Leo Bodnar’s brilliant B-64, as I write, currently on it’s 6th pass around the world past it’s launch point in Silverstone. Once the JOTA2 payload was attached to the foil balloon, kindly supplied by Steve of Random Engineering, I opened up the valve with a straw, the recommended method, and started to fill it. Once the balloon was just about able to lift the payload, Chris suggested we add a small weight. I attached 1.2g of solder on the bottom of the payload. We added some more Helium into the balloon but after testing, it seemed too spritely. Perhaps I’d added a few too extra ‘Stirks’ of gas. I extracted some of the gas with a straw after which Chris and I decided that the ascent rate was just right.
The rough measurement of gas equal to a ‘puff’ required to be added or extracted to/from an arbitrary volume of gas in a balloon envelope totaling exactly the correct amount for a given flight.
Abbreviation: STK. – Origin 2011-; named after A. Stirk
Luckily, we were filling the balloon in a tent so it was an easy job to check and re-check the ascent rate by letting the balloon rise to the ceiling. This was a critical to enable the balloon to get into float condition.
Because JOTA2 was going to ascend very slowly, it was essential that it miss any obstacles on the site, namely the trees. During the preparations of the event, Mike had told me about a climbing tower that was on site and on the Saturday, after a brief reccy, I decided that it was definitely the platform for the launch. Shortly after 10:00am, I donned a safety harness, not the most dignified of things to put on!
However undignified it was to put on, I soon realised that it was essential to keep me safe. The tower is 11m tall and I wouldn’t fancy that fall. I climbed the tower with the aid of Clive without mishap, albeit inside the tower up a ladder rather than on the outside, and the view was great. Kingston Ridge is about 90m Above Sea Level so we were around 100m ASL for the launch, excellent!
I fed a line down for the balloon and Chris attached it. I brought it up slowly while Clive made sure the balloon didn’t foul on the footholds on the side of the tower.
By this time the Scouts had assembled down below and once I had detached the line from JOTA2, I waited for a lull in the light breeze. When I was happy, I called for a countdown. Everyone shouted…
JOTA2 Launch Video – courtesy of Pete Sipple
JOTA2 climbed very slowly and thankfully missed all the trees. I carefully climbed down the tower after grabbing a quick snap on my iPhone.
Almost simultaneously, the Scouts launched their tagged balloons, some of which you can see in the image above, following JOTA2 into the sky.
Chris and I were very pleased with how JOTA2 ascended. It was 1m/sec and lower for most of the time. This was looking good for a Float. As JOTA2 continued, we had many Scouts and helpers coming into the tent for updates on how far JOTA2 had got and how high it was. Most were impressed with it’s progress.
To begin with, there was an issue decoding. Chris reported only one ‘$’ character at the beginning of telemetry sentences. He was also missing some sentences completely. I couldn’t understand this. Although I had reduced the ‘$’ characters from four to two, they should have still showed up. The ‘$’ characters indicate to the decoding software that a sentence is about to start. Chris soon found that the radios Squelch was set high, this was suppressing the beginning of the telemetry signal. Once it was opened up, all was well and we got solid strings.
Early JOTA2 telemetry string “$$JOTA2,10,09:08:51,51.559334,00.435543,88.2,0.52,1,1.41,6*6897”
JOTA2 continued to climb slowly into the afternoon and Chris and I wondered if it would get into a float. By this time, the camp was beginning to wind down and we only had a short time left to run the generator. JOTA2 was just beginning to level out though so we thought it was likely that we’d have our floating payload. Both Chris and I helped dismantling the tent and were very pleased to be presented with a gift for our contribution to the event in a ceremony culminating in a traditional Scouts Oggy.
Mike brought me home and I continued to track JOTA2 from there via Tracking Page. By this time I was very tired but continued to watch as JOTA2 successfully ascended into a nice float and crossed the Northern part of The Netherlands and on into the Baltic. At 18:13UTC, Stations SP1TMN-6 & SM7DSE received the last full telemetry string from JOTA2 having just .75v left in it’s AAA Lithium battery. JOTA2 had almost reached Latvia, more than 1000kM from launch and I’ve no doubt it did fly on and reach landfall.
All in all, two very successful flights over the weekend which, although being fun for Chris and I, successfully demonstrated two types of High Altitude Ballooning to Scouts and adults alike. This was the primary aim.
I’d like to take this opportunity to thank Chris Stubbs for all his assistance over the weekend, and without his guidance, JOTA2 may not have gone into Float. Clive for keeping me safe on the climbing tower. Pete Sipple for his help, loan of Laptop and radio for tracking, photograph taking and images. Dave for getting me to the site. Mike for inviting me in the first place and use of his radio and all of the Scouts, Leaders and Staff at Kingston Ridge Campsite for their enthusiasm and welcome (and Bacon rolls on Sunday!). As you can tell, I really enjoyed the event and I look forward to next year!