[HN Gopher] Tracking Pico Balloons Using Ham Radio [pdf]
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Tracking Pico Balloons Using Ham Radio [pdf]
Author : jah
Score : 71 points
Date : 2020-07-11 15:16 UTC (7 hours ago)
(HTM) web link (www.harc.net)
(TXT) w3m dump (www.harc.net)
| JKCalhoun wrote:
| This is the coolest thing I have seen this year. I think I always
| wanted to do such a thing, circle the earth with a balloon -- had
| no idea it was within reach. I love all the ways in which they
| shaved weight on the payload.
|
| I suppose having heard about the gas-powered model plane that
| crossed the Atlantic decades ago started my obsession. Then
| learning about the Japanese fire balloons that crossed the
| Pacific in WWII....
| pugworthy wrote:
| This kind of reminds me of CubeSats. I love the simple little
| design with the side solar panel wings.
| i_am_proteus wrote:
| Whenever I see things like this in light of the various threats
| to amateur radio (usually from various interests who would like
| to get the frequencies sold at FCC auction for commercial use),
| I'm reminded of the tremendous value this hobby adds to
| engineering education. So many of the engineers I know who work
| with radio got started by tinkering with amateur gear.
| Stratoscope wrote:
| Related discussion from yesterday:
|
| https://news.ycombinator.com/item?id=23795913
| themodelplumber wrote:
| Wow, that's amazing. 22 laps around the world over the course of
| one year. And HF data rx in Australia from this tiny circuit
| board attached to a tiny balloon over the mid-atlantic. Worth a
| read. Also bonus Windows XP points.
|
| Btw how are they flying a circuit board in the raw without
| damaging environmental effect from water? I'm new to this part of
| the hobby.
| th0ma5 wrote:
| Maybe they just put on a thin layer of conformal coating?
| sgt wrote:
| What about clear coat paint you would get from a hardware
| store just before launch?
| djaque wrote:
| I've always used clear nailpolish as a hacky version of
| conformal coating.
| 0_____0 wrote:
| fwiw You can get urethane and silicone conformal coating in
| a spray can and it's not _that_ expensive.
| trophyhead wrote:
| At the altitudes these are flying at (10km+), the air is bone
| dry. Unless moisture is encountered on the ascent, there is no
| need for conformal coating.
|
| P.S. - I've done a fair number of these flights and can speak
| in more detail about this hobby on request. Great fun!
| mcculley wrote:
| Can this frequency/protocol be used from sea level? I have some
| boats offshore that I would like to track. We currently use a
| combination of AIS and SPOT trackers.
| lxe wrote:
| I'm guessing it's possible. I think WSPR supports a wide
| selection of bands so you can have over the horizon comms. APRS
| is usually VHF/UHF so it's mostly line of sight. On land, there
| are APRS repeaters that rebroadcast your signal at higher power
| so I'm guessing it's more suited for land.
| trophyhead wrote:
| You can, but you may not get the results you're looking for.
|
| APRS is a line-of sight signal. In a balloon, you might be
| heard by transmitters 200 miles or so away. On a boat, I'd
| expect that range to drop to 50 or less. So if you're out at
| sea, it's unlikely you'd be heard when you're much outside the
| view of land.
|
| WSPR has a very long range, but the density of information
| transmitted is very low. Each transmissison takes about 2
| minutes and the tx rate is around 5 baud (not 5kb...5 baud!).
| The protocol was developed to test the range of ham radio
| antennae and it doesn't give you much more than the
| transmission voltage and the 'maidenhead' coordinates (which
| will give your location within a roughly 80 mile box depending
| on your latitude).
|
| If that rough estimate of your position is good enough, WSPR
| may be useful to you for tracking a boat. Some balloon trackers
| also transmit a secondary signal under a different callsign
| with some more advanced telemetry information, such as
| altitude, speed, more granular position within a 2 or 3 mile
| box.
|
| Also, you'll need an antenna of some length. My balloons
| transmit on the 20m bands, which means it has a 17 foot antenna
| both above and below the tracker constituting a half dipole
| (it's 36 gauge magnet wire so weights almost nothing. If your
| boats are big enough to cross oceans, you can likely mount them
| in a way where you'd be heard.
| lxe wrote:
| What's the purpose of that capacitor?
| JKCalhoun wrote:
| As the other person responded, basically a battery back-up.
| [deleted]
| trophyhead wrote:
| These are run by solar panels that only transmit during the
| day. The capacitor just gives a half a minute or so in the
| event of brief cloud cover, panel not facing the sun at a good
| angle, etc. Not strictly necessary, but since a WSPR message
| takes almost two minutes to send, a good idea to not have it
| abort in the middle of the transmission due to lack of power
| for a couple of seconds.
| hanoz wrote:
| Why is the UK (in the unusual company of Yemen and North Korea)
| an important "do not transmit zone"?
| trophyhead wrote:
| Airborne transmissions of this sort are not legal over the UK,
| North Korea, or Yemen. Guessing it's a leftover rule from WW2
| in the case of the UK, not sure.
|
| These transmitters typically have geofencing routines that turn
| off the transmission when flying over these countries.
| hanoz wrote:
| But in my brief attempt to answer my own question I only
| found pages detailing pico balloon launches _from_ the UK.
| trophyhead wrote:
| I'm sure people in the UK are doing launches, but it's
| illegal for them to transmit when flying in UK airspace.
|
| In reality, it's an almost unenforcable law to begin with.
| Most of the WSPR transmissions are on the order of 10mW
| (probably similar to the Bluetooth output of your cell
| phone). It's not unusual for these transmissions to be
| heard several thousand miles away, which is quite amazing!
| CraigJPerry wrote:
| Yeah unfortunately the uk amateur radio licence (at all
| levels) prohibits airborne use of the licence.
|
| I know for other amateur balloon experiments such as
| weather balloons, they often use the ISM bands instead in
| the UK.
| kokey wrote:
| If I remember right is the reason is that it's illegal do
| use amateur radio bands on something that is flying, so
| that excludes APRS. However, using the ISM bands are fine
| so that's what people in the UK tend to use, but it means
| no APRS and you have to have people tracking you in other
| ways (e.g. sending your telemetry over LoRa or RTTY)
| ECA_stax wrote:
| http://leobodnar.com/balloons/
|
| more reading
| jimnotgym wrote:
| I love Leo Bodnar's stuff. I made a 'flight sim' joystick and
| pedals from one of his boards
| bfirsh wrote:
| The tracker is very cool: http://habhub.org/
|
| It's a crowdsourced set of antennas around the world that upload
| data to central server (think Flightradar24 for high altitude
| balloons). It's been running for 15 years or so.
|
| Various bits of more reading if you're interested in this stuff:
| http://picospace.net/ https://ukhas.org.uk/
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(page generated 2020-07-11 23:00 UTC)