Archive for the ‘diy’ Category

How to Build the World’s Lightest Quadrifilar Helix Antenna


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:


Toner Transfer and Muriatic Acid Etchant: Making PCBs at LVL1


Originally posted on my personal blog, Meat and Networking.

LVL1 is great.  A place for creative and motivated people to get together and goad each-other into doing more creative things.  It’s also a great gathering place for tools, as well as knowledge.  A few months ago, the spoiled electrical engineer that I am, I never would have considered making my own PCBs.  Any project worth taking off the breadboard was worth sending to China to get made “right.”

Of course, there isn’t always time and money to send something to China.  Today’s installment is the Sumo-bot board I’m trying to put together for the Hive13 sumobot competition.  Unfortunately, it doesn’t look like poor Snoopy bot will make it to the ring, but the board making process itself is worth talking about.

Laying out a PCB using software like Eagle is beyond the scope of this post.  If you can follow the appropriate Sparkfun Tutorial, it’s pretty easy to pick up.  Something to note:  for single sided home-made PCBs, put all traces and surface mount components on the BOTTOM layer.  Put any necessary jumpers on the top layer.  When you’re ready to print, just turn off all the layers you don’t want turned into copper.


Are you a maker?


Dale Dougherty, Make Magazine publisher did this nice Ted talk on Makers. If you are ever looking for a good way to tell people what LVL1 is all about, have them watch this video. BTW, Dale is from Louisville and visited our Hackerspace last summer.

Car-B-Gone workshop TODAY


We are having a Car-B-Gone workshop at the space this afternoon. Sorry we did not get the Eventbright announcement up. Just show up to build your very own Car-B-Gone tonight at 8-ish. If you do not know what a Car-B-Gone is… it is another fine Mitch Altman project. Read about it here

Following the Car-B-Gone workshop will be the ever popular Beer-B-Gone workshop. Hope to see everyone there.


LVL1 Hackerspace
1205 E. Washington St.
Louisville, KY 40206