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Another day, another repost from another project I'm working on. This time, from White Star Balloons, the world's lightest quad helix antenna.

After the scrub on the launch pad for flight attempt A, we went back to the books, to try and figure out what we could do to improve our odds the next time around. One of our biggest setbacks was the inability make an antenna suitable for our use: We needed an antenna tuned for 149 MHz, not needing a ground plane, weighing as little as possible.

After 4 tries, and some expensive test equipment, the end result was a Quadrifilar Helix antenna weighing only 80 grams!

Our ground test antenna was a 5/8ths wave whip antenna, which works well, but unfortunately needs a ground plane. Tests with both a quarter-wave dipole and a J-pole antenna were lackluster. Documentation from our satellite service provider implied that a quadrifilar helix antenna would provide the best coverage at all. While these antennas are pretty, their design and construction was voodoo magic at first.

Thanks to some design documentation here: and some help from the balloon community, we had some baselines for creating such an antenna. We still went through *quite* a few revisions.  We went through 3 revisions that didn't work, and one which works pretty darn well!

Here are the antennas which didn't work:

...continue reading "How to Build the World’s Lightest Quadrifilar Helix Antenna"


Yuri's Night

This Tuesday is shaping up to be a Super Tuesday!  Tuesdays at 8:00pm are our regular meeting times, but this Tuesday, 4/12/11, we're throwing in a Sumo-bot throw-down, and a Yuri's Night  Celebration.

What: LVL1 Tuesday Meeting, Yuri's Night Celebration, and Sumo-bot throw-down!

When: Tuesday, April 12th, 2011

Where: The LVL1 Hackerspace, 814 East Broadway, Entrance on the rear alley

For visitors, our regular meetings usually consist of 30 minutes of talking about LVL1 business, events, and miscellany, followed by building, hacking, making and general mayhem, extending well into the night.  This Tuesday, however, we'll be celebrating Yuri's Night, a world-wide party commemorating the 50th anniversary of mankind first slipping the surly bonds of earth, and extending our reach into space.

LVL1 will be hosting members of the Louisville Astronomical Society for some urban star gazing, and we'll be trying to listen for the ARRISat, an amateur radio satellite currently attached to the International Space Station, transmitting just for Yuri's Night, before it becomes fully armed and operational later this year.

In addition, almost a dozen members of the LVL1 community have been working on Sumo-bots for the upcoming tournament at Hive13, Cincinnati's hackerspace.  We've got enough bots running around here for our own tournament, so we'll be doing exposition matches all evening, building, testing and tweaking our sumos!

Come one, come all to LVL1 this Tuesday at 8:00pm.  Anyone and everyone is always welcome.

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Change of plans everyone! SpeedBall-1 is going to be launched *very* soon. By soon, I mean that we're planning to launch within the next week or two. Why? There are several reasons:

One, we're basically done with SpeedBall-1 and are just working on finishing the last of cryo tests to fix any remaining bugs related to operating in such cold temperatures.

Two, we don't have much time left to catch the jet stream this season. The jet stream changes according to the seasons, and according to the National Oceanic and Atmospheric Administration (NOAA) data models we've calculated, we're running out of time to catch the particular stream we need to hopefully hitch a ride to Europe, but possibly North Africa instead, since it's impossible to predict the actual path the balloon will take in the jet stream. Also because of the limited time and amazing progress we're made in putting everything together, SpeedBall-1 will be a full, trans-Atlantic flight, and not just a test of systems like previously planned.

Third, and something we realized after deciding to make the full, trans-Atlantic flight, we found out we have some tough competition! Cornell University has had a multi-year project to do basically what we're doing -- set the record for having the first amateur trans-Atlantic balloon crossing, and possibly farther. The difference? They started back in 2008, and have a huge, multi-disciplinary team of graduate students working on this full-time with full financial backing (from Lockheed-Martin, no less). Given that we're a small hackerspace with limited time and resources, and started from scratch August 2010, what we've accomplished so far is nothing short of astounding. They're planning to launch on Feb. 21st, so we don't have much time left!