A last update on this thread from me, or at least probably for a few weeks. The balloon flew north into Ukraine last night and into a region with very few TTN gateways and virtually none with outdoor antenna. So I wasn’t expecting it to check in early this morning and it didn’t but a couple of hours later a single gateway established contact for an hour or so and gave the balloon’s position as close to Kiev.
The gateway, which was in Kiev itself, was an indoor one according to the TTN website and I can only guess it has a view of the sky through a window.
Short though this “drive by” contact was it was reassuring to see the balloon is staying at the same altitude.
The balloon is likely to swing east over the coming day or so. There is a chance it could swing back west into Europe but this is a lower probability than an eastern route although the weather can never be predicted with precision. If it does go east it will pass a little north of Moscow and then if it is very lucky probably reach the Pacific somewhere near Japan. If very, very lucky it will return to Europe via the Atlantic in about three weeks.
If the balloon does swing back west I will post an update tomorrow otherwise, it it goes east we will all have to wait and see if it pops up again next month.
Joe, the earliest it might reappear will be towards the end of this week. They can stay in the air a long time. I think the record is something like 17 circumnavigations of the world which took a year or more.
John
The problem is different parts of the World use different TTN frequency plans. The Imperial College of Science in London built a tracker which uses the gps to work out what frequency to use, depending on where it was. But I’m using off the shelf components and the transmitter is 968MHz only. It probably could transmit weakly on different frequencies but the coding required (in C++) to get the geo-fencing required to change plans was a bit beyond me at the time. I may yet try again but I now have the special licence from Ofcom to use WSPR on the 20m band from a balloon so my efforts now are going down that route. Its amazing what ranges 15mW of WSPR can do at altitude - thousands of kilometres.
Cheers. Hopefully the balloon will ping into life over the next couple of weeks and say hello!
Looking forward to seeing the results of a 15mW of WSPR on 20m.
Thanks, I wasn’t sure about doing the interview but it seems to have worked out OK - apart from getting an email today from I think a “flat-earther” asking about the reference to “curvature of the Earth”. I’m ignoring them.
If anyone wants to see the article, and a photo of me (you have been warned!) this link might help. It doesn’t seem to behind a pay wall.
Sadly no, it’s slightly irritating not knowing how far it got but that’s the limitation of the TTN network as it could only track the balloon in Europe.
The answer is WSPR and I’ll try again in the summer, possibly using 10m instead of 20. Someone recently flew one using 10m and they got good coverage around the globe. The shorter antenna saves a little weight but the main advantage is it is easier to handle during the launch.
Thats a bit of a bummer but as you say, limited by the TTN network coverage.
WSPR might just be the solution. There are quite a few WSPR stations around. Good luck.
What’s the reason for that limitation? The different frequency allocations for LoRa (e.g. here we have 915MHz in place of your 868MHz) or do TTN geographically limit what gateways a device can connect through even if the frequencies are available?
Sorry if I wasn’t clear, my tracker could only work on the European channels. In theory you could make one which changed frequency as it floated around the globe but after Europe there are hardly any ground stations (gateways) until you reach Japan. If it missed Japan the next place it might find a TTN gateway would be North America and there are few in the northern regions of Canada.
Range is also limited to around 350km which is not much compared to the size of say the Pacific.
This is why HF WSPR is the most popular choice, allowing balloons to be tracked almost anywhere except the polar regions - which some have visited, emerging after a few weeks of silence.
Edit: I’m being misleading again! WSPR does work in the polar regions. The problem is the balloons don’t because the sun is too low in the sky for the typical flat solar array used. Some pyramidal arrays have been made which work much better with low sun angles.
