My last three articles in Nuts and Volts cover this topic. I have notes and code in each article.

Our Civil Air Patrol Squadron got some Raspberry Pi kits for STEM activities. We might have a couple left over when we are done. I am wondering if there are any kits or additional "sensors" we can add

Crossposting this from the APRSSIG, since there are so many aprs.fi users here. 73 de Mark N9XTN Date: Tue, 16 Oct 2018 09:32:36 +0300 (EEST) From: Heikki Hannikainen <hessu@...> To:

I'm experimenting with a free monthly astronomy newsletter. If you're interested, you can subscribe at, https://stargazingalmanac.substack.com/

Here here! It was a great event in 2013.

Mike, Looking forward to it! We really enjoyed our time in Pella at your last GPSL. 73 de Mark N9XTN

GPSL will be in Pella, IA,, June 13, 14 and 15. Genelle is planning to recreate our Wednesday evening picnic at our house for those that come in on Wednesday afternoon. We are busy planning an

Hi Sorry for the short notice but things have been a bit hectic. On Sunday morning, September 30 I launched my first floater, VA5BNC-15 from Saskatoon, (52.1N, 106.6W).  It survived the first night

Don't forget the weight of that Giant Balloon! My "LITTLE" 300,000 Cubic Footer weighs 31 pounds Joe WB9SBD The Original

Hank, nice job on going the next step with the math which I didn't do. 73 de Mark N9XTN

The usage of helium for the typical amateur balloon refers to ground level conditions, similar to Standard Temperature and Pressure which is 20 Celsius and 1013 millibars pressure. The 60 million

Can you imagine paying that kind of money for a balloon launch? A flight into space on a Falcon 9 is about the same price.

If the goal was max altitude I'm surprised they did not use H2? Joe WB9SBD The Original Rolling Ball Clock Idle Tyme

Well, if you figure ~250 cu ft for a typical 1200g balloon, around 240,000. That's a lot of ARHAB flights! If they were paying commercial rates for their helium (which I think is approaching $1/cu ft

How many balloons could we fly with 60 million cubic feet of He? ;-)

https://www.space.com/41791-giant-nasa-balloon-big-60-breaks-record.html

Yes, the first step is at 36K as mentioned in my first post. The next two are at 65.6 Kfeet and 105 Kfeet. So up to 105 Kfeet there are three regimes of the Standard Atmosphere: 0 - 36, 36 - 65.6,

Hi Mike, We've flown the MS5611-01BA03 with good success. It is specified down to 10mb. Even without setting the local barometric pressure, it is generally within 100 Ft of actual altitude at

The  MS5611 is a better chip to use for HAB - its rated down to 10mbar (approximately 28km).   Both the BMP180 and BMP280 have an erratic output value issue outside of their rated range.    

You could get a sounding for the day for a little refinement. I just tried that and there was a difference of 360 meters from the Standard Atmosphere. That height is subject to the radiosonde system