Ps. I'll link to this from my *wave* post this one just got finished first...
I didn't find a similar thread (altho I only looked through the first 3 or 4 pages of threads)
So I'll start and from the out of left field side of things. I figured I'd post a little craziness about me.
I've been a Ham Radio operator for more than 25 years (and I'm really not that old
And because I like to thinker and build things. A couple of years ago, I designed a really light, small, portable radio complete with GPS, solar, battery, charging etc. Glued that to a 3' party balloon and let it go.
That looked like this

and the first board designed was this - (it has processor, radio, gps, power supply, solar charger, etc) This version weighed about 24grams all in with battery, etc. If flew at 24-26k feet and in this case it survived for 2 days at pretty much 24hr's a day.

So fast forward a year. Technology changed and I decided to design a replacement with a specific task. Be as light as possible, and flexible as possible and provide location information every day.
The first version used a ham radio method called APRS and while there is a network of receiving stations world wide, there are large areas of the globe that are NOT covered. Others that have flown like this, will go for many days crossing the oceans, etc and never know where their balloon is. I was going to solve this problem.
So meet the current generation board. It weight considerably less. It's < 1 sq in in area, and weighs ~ 1 gram when built. In full flying configuration it weighs about 8grams, power, board, solar, and antennas.

a one rev prior Board with AA battery for perspective

This version uses the same APRS mode of relaying it's position, but it also uses a different way that is also listened for on a world wide network of receivers, but has pretty much global coverage.
Here's an example of a recent flight and it's coverage footprint. The balloon is the K4JCW callsign. The others are people who heard it and relayed its position.

Now fast forward to today. I have 3 of these in the air. They were launched at various times spanning back to 8/22 as the oldest one. It and the one launched on 9/8 have a hardware issue that prevents them from starting up every day. It's kinda hard to think through all the issues at -60C temperatures and that one got me. I resolved that in the one that was launched on 9/20.
Specifically
hirfw-3 launched 8/22
hirfw-5 launched 9/8
hirfw-6 launched 9/20
They are all flying at around 46k feet on a custom balloon, they have all been around the world a number of times. And at least with -6 it checks in every day. They are all solar only, so they only function during the day. Trying to get a rechargable battery to work at -60C during the night has proven to be impossible.
Here is the site I go to to track their positions
https://tracker.habhub.org/#!mt=roadmap&mz=1&qm=All&mc=26.77911,96.98119&q=hirfw-3;%20hirfw-5;%20hirfw-6
Just a little craziness to have fun with on a day over day basis, that isn't JEEP related
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