We’ve reported on “space” balloons before. Heck, some of us have even launched a few. Usually they go way up in the air, take some cool pictures, and land within driving (and retrieving) distance the same afternoon. You get often amazing photos and bragging rights that you took them for the low, low price of a really big helium balloon and a fill.
But what if you shrunk everything down? Over the last few years, [Andy, VK3YT] has been launching ever smaller and lighter balloons with very low power ham radio payloads. So no camera and no photos, but the payback is that he’s launching payloads that weigh around thirteen grams complete with GPS, radio, solar cell, and batteries. They can stay up for weeks and go really far. We’d love to see some construction details beyond the minimalistic “Solar powered party balloon, 25mW TX”. But that about sums it up.
Did we mention that this “party balloon” started off in Australia, visited Africa, crossed over Australia again, visited Africa a second time, did a heart-shaped loop just outside Jakarta, and landed in Australia?
The payloads send very slow (QRSS), very low power (QRP) radio signals on a couple channels and using two different encoding schemes (WSPR and JT9) to maximize the chances of someone on the ground picking them up. The choice of the relatively low-frequency 20m and 30m bands helps a lot with long-distance signal propagation at low wattage levels.
To conserve power, the beacon only broadcasts a few times per hour unless the battery is fully charged. Receiving stations use software-defined-radio techniques to tease the low, slow signal out from the noise. And when anyone receives the signal, they can upload the telemetry data to habhub, a high-altitude balloon tracking network, to figure out where it’s from and where it’s going.
Twice around the world is incredible. But note that it’s [Andy]’s 46th such balloon. His first pico-balloon (PS-2, ironically) only stayed up for fifteen hours and made it under 800km away. Practice makes perfect?
We’ve written up WSPR on a Raspberry Pi (code and hardware) if you’re interested in getting started on WSPR on the cheap.
Thanks to [Bill Meara] of Soldersmoke for the tip.
13 thoughts on “Pico Space Balloon Circumnavigates The Globe, Twice”
It hasn’t landed yet, still floating. It’s a great use of HF radio, previous circumnavigation flights used only UHF and where out of contact when over the oceans. Those where the B-* flights from a few years ago: http://hackaday.com/2014/10/19/high-altitude-balloon-keeps-going/
Thanks to Lora™ (Semtech’s “Long Range” spread spectrum technology) UHF links have made great leaps in recent times. LoRa™ ranges are at least an order of magnitude greater than devices using FSK transmitters,with 100s of km LoS typical from 10-25 mW transmitters on the licence free 433 MHz band. The LoRa™ limiting factor aloft is usually the earths curvature. Data rates are much better than HF “fuzzy modes” too – 100s of bps – & only simple antenna & LoRa receivers are needed too. Many HF “fuzzy mode” hams – myself included – use costly specialised “YA-KEN-COM” ham gear. 73s de ZL2APS
Extra: See a heads up => http://www.instructables.com/id/Introducing-LoRa-/
Why do you keep posting about this stupid system in the comments? Andy didn’t use LoRa, because it sucks shit.
2 meters would work great if you had line of sight, 20m is desired as they are trying to get comms over the horizon to get all the position reports. you could simply do an APRS beacon with an arduino into a baofeng 2M handi and cheaply do the same thing but it will require ground stations around the globe to look for it, and you will not get the regular updates for location.
I have done 500mw 2 meter communications over 250 miles to a balloon and even then it was still strong, 50 miles is useable as the balloon will never really get past 25 miles up, and you have about 250 miles of range before it drops below the horizon.
Antenna design is important, so an inverted quarter wave with the radials not at 45 but at 33 degrees will give you a tipped pattern that is more towards the ground and just a little off from 50 ohms (more like 55 ohms) I have seen turnstile dipoles at 90 degrees as well create a very nice ground pattern.
No photos of the balloon! I would like to see it. And what the antennas look like? Are they long wires hanging under the balloon? A quarter wave at 30 meters is over 7 meters long…
Seems like a good time to plug my own somewhat similar project. It’s an APRS transmitter designed for weather balloons that measures 1.75″ x .75″ and 55 grams with a pair of AAs. Source code and schematics / board are coming soon™, until then here is the hackaday.io page:
That’s, like, 4 times heavier than Andy’s solution. Not even on the same scale.
What are people using for WSPR transmitters on these balloons? I read about it, but I didn’t see the device itself.
I wonder if the driver for VK3YT’s miniaturization is that there’s a lot less hassle launching free balloons in Oz if (per CASR 101.145) the payload limit is under 50gm. http://www.rmac.riverland.net.au/101casr.pdf
This is what it looks like:
About 15-20 years ago I heard of a group of amateur radio operators in the Wichita, KS who would build payloads that could be launched by party balloons. I don’t recall the nature of the payloads, but it seemed to be that they launched them to track them. We where told at least on vendor would deliver them within a certain distance, so they where dispatched to some rural intersection.
My new Skytracker APRS tracker board weighs 6 grams and can be easily flown from a 36-inch Mylar party balloon. My second flight test launched from the Huntsville, Alabama area was totally solar-powered stayed aloft 3 days at 23,000 feet and was last heard from about 250 miles east of Florida on its way to the Caribbean. Alan W7QO in Atlanta has developed an APRS board that weights around 2 to 3 grams and has been flying his on 36-inch Mylar balloons this week as well. – Bill WB8ELK
It’s hard to find open source code for these balloons, so I made my own. Its open for everyone to see.
Please be kind and respectful to help make the comments section excellent. (Comment Policy)