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High-Altitude Adventure with a DIY Pico Balloon

spectrum.ieee.org

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Re: High-Altitude Adventure with a DIY Pico Balloon

#11

Post by SuperMouse »

iberator wrote: post #10
SuperMouse wrote: post #8

I'm currently thinkering of building a balloon with a 2.4GHz LoRa transmitter (SX128x) and a low-power STM32U microcontroller. Why? - You can repurpose 2.4GHz Wifi gear opening many doors - You can easily include volunteers dumping data from HF into a IP sink for telemetry. TTGO offers boards with 2.4GHz LoRa. - Theoretically you still can add a "low rate" 868MHz/433MHz and a "high rate" 2.4GHz for transmitting pictu…

lol. WPRS works like 10.000km per WATT on HF. You can't do it with 2.4ghz. Ham radio basics

lol. 10.000km with a few bits of fixed-structure payload you mean.

Encoding basics

Re: High-Altitude Adventure with a DIY Pico Balloon

#13

Post by AtlasGains »

This is way cooler than I expected. I had no idea you could do near-space stuff for the price of a dinner, or that ham radio networks like WSPR could track something globally without satellites. Feels like one of those “old tech + clever hacks” projects that shouldn’t work but somehow does. Also kind of wild that a party balloon can end up halfway around the world.

Re: High-Altitude Adventure with a DIY Pico Balloon

#15

Post by ErroneousBosh »

iberator wrote: post #10
SuperMouse wrote: post #8

I'm currently thinkering of building a balloon with a 2.4GHz LoRa transmitter (SX128x) and a low-power STM32U microcontroller. Why? - You can repurpose 2.4GHz Wifi gear opening many doors - You can easily include volunteers dumping data from HF into a IP sink for telemetry. TTGO offers boards with 2.4GHz LoRa. - Theoretically you still can add a "low rate" 868MHz/433MHz and a "high rate" 2.4GHz for transmitting pictu…

lol. WPRS works like 10.000km per WATT on HF. You can't do it with 2.4ghz. Ham radio basics

Why do they do WSPR on HF and not 2.4GHz?

What's the important part that defines what kind of range you can get?

Re: High-Altitude Adventure with a DIY Pico Balloon

#17

Post by ErroneousBosh »

radeeyate wrote: post #6
bambax wrote: post #5

This sounds so cool! > I’m a little puzzled about the balloons’ telemetry messages received on the WSPR network, as they have been few and far between. But wouldn't there be a way to send messages to Starlink satellites instead of WSPR? Is it a problem of power consumption? (It would be great to be able to transmit images, not just GPS pings).

If you are wanting to send images, there are already some cool ways to do that: either SSTV ( https://en.wikipedia.org/wiki/Slow-scan_television ) or Wenet, which sends them at a much higher speed: https://github.com/projecthorus/wenet .

I wrote some code to send SSTV because everything was either proprietary and didn't work, shareware and didn't work (and often with the original author gone Silent Key so no way to get the real version), or under some vaguely-specified licence and written with Tk widgets in Fortran or some damn thing.

I wrote it about 25 years ago and can't currently find it but it's one one of these hard disks in these here blue moving crates somewhere. It'd take less time to recreate than find, I suspect, especially if I also wanted to make it build nicely in gcc from this decade.

It just grabbed from a V4L2 source, and emitted a burst of Robot36 over the soundcard. In conjunction with a heavy-duty Tait T2000-family transceiver I used it to livestream a drive across Glasgow, slowly and noisily, sending one picture per minute which gave the poor PA transistor time to cool a bit ;-)

Re: High-Altitude Adventure with a DIY Pico Balloon

#18

Post by maccam912 »

ErroneousBosh wrote: post #15
iberator wrote: post #10

Earlier quoted context omitted.

lol. WPRS works like 10.000km per WATT on HF. You can't do it with 2.4ghz. Ham radio basics

Why do they do WSPR on HF and not 2.4GHz? What's the important part that defines what kind of range you can get?

WSPR on HF makes sense down here on the surface of the planet because certain ranges of frequencies (not the same range always, but generally always within HF) can bounce off of upper atmosphere layers and pinball back and forth to get signals to someone or from someone who couldn't be seen line-of-sight because of the curvature of the Earth. For line of sight work, the 2.4GHz in theory would work as well as anything, but another trick WSPR has is that it doesn't allow for arbitrary data to be sent. Sender and receiver encode the limited information in an agreed-upon way and then it takes a long time, like minutes, to send that little bit of data. Very high redundancy.

Re: High-Altitude Adventure with a DIY Pico Balloon

#19

Post by superkuh »

I wish the regulations around HAB were not so lighter-than-air gas centric. Hot air balloons are much more accessible, especially solar heated hot air balllons. But they have much less lift per volume and so the FAA FAR 101 rules basically say they all have to be treated as the type where you inform the FAA beforehand and then every hour about their position among other things.

https://www.ecfr.gov/current/title-14/chapter-I/subchapter-F...

>any balloon that is moored to the surface of the earth or an object thereon and that has a diameter of more than 6 feet or a gas capacity of more than 115 cubic feet.

And the regulations on tethered balloons end up being even stricter than letting them go.

Re: High-Altitude Adventure with a DIY Pico Balloon

#20

Post by ErroneousBosh »

maccam912 wrote: post #18
ErroneousBosh wrote: post #15

Earlier quoted context omitted.

Why do they do WSPR on HF and not 2.4GHz? What's the important part that defines what kind of range you can get?

WSPR on HF makes sense down here on the surface of the planet because certain ranges of frequencies (not the same range always, but generally always within HF) can bounce off of upper atmosphere layers and pinball back and forth to get signals to someone or from someone who couldn't be seen line-of-sight because of the curvature of the Earth. For line of sight work, the 2.4GHz in theory would work as well as anything…

You know that and I know that, it was a Socratic question aimed at OP ;-)

In the olden days we did QRSS, FSK Morse with a dot rate in the order of minutes.

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