WiMax antenna with auto-positioning system

posted Jun 8th 2010 1:00pm by Mike Szczys
filed under: wireless hacks

[Andrew] certainly brings a bit of a James Bond feel to connecting to your WiMax base station. He built this antenna along with an auto-positioning system to get the strongest signal possible. The device, which appears a bit fragile, breaks down into a nice little case. When you get to your next checkpoint you can set it up and the stepper motor along with an ATtiny2313 will rescan to get you on with your mission as fast as possible. This is one of our favorite antenna builds so far, and we’ve seen a lot of hacked antennas. Don’t miss the action-packed trailer after the break.

Comments [13]

tagged: antenna, attiny2313, stepper, WiMax

13 Responses to WiMax antenna with auto-positioning system

hellbringercid says:

June 8, 2010 at 1:28 pm

ha ha, yes very fragile, would not want to take that outside on a mission.

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Michael L. says:

June 8, 2010 at 1:30 pm

I’d personally like to see more build details and some code for the microcontroller. This seems like it’d be a fun afternoon project.

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oxid says:

June 8, 2010 at 1:47 pm

could be cleaner.

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Joe says:

June 8, 2010 at 1:58 pm

So, what exactly is it optimizing? RSSI? CINR?

I’d guess that it’s optimizing RSSI. I’m not 100% sure that’s necessarily optimal for a system that implements MIMO. I’m also curious about cell edge performance, where optimizing RSSI in a system with N=1 reuse might just mean it’s picking up signal from 2 base stations and effectively maximizing interference.

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Necromant says:

June 8, 2010 at 2:24 pm

Well, I have created this little thing for usage mostly outdoors, with only one BS around. Out of town, I don’t have a really big choice, since the territory officially does not have any network coverage. But ofcourse it is best to work tuned onto one BS, with no switching.
While now, the algo is quite simple – I just check the output of madwimax and try to find the angle with the best CINR. I will carry more tests later this month, and perhaps switch to a logoperiodic instead of a biquad.

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Necromant says:

June 8, 2010 at 2:41 pm

For those eager to make your own: grab all the stuff I have here: http://necromant.ath.cx/projects/wi-radar-0.1.tar.gz
It’s not very well documented/annotated, since I like to keep to many things in my head, but I will try to fix that later.

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DerAxeman says:

June 8, 2010 at 2:52 pm

Is it worth while to invest so much time into this? Everyone will be switching to LTE and wimax is going to die out.

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ICan'tTellYou says:

June 8, 2010 at 3:22 pm

Looks pretty good, but it could be cleaner.

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Jimmacle says:

June 8, 2010 at 3:23 pm

Looks pretty good, but it could be cleaner.
P.S. I’m not copying, I changed my name.

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cannonface says:

June 8, 2010 at 8:00 pm

I built one just like this 5 years ago for wifi sniffing by following some guide. Dunno what’s the exact name of this antenna, maybe fragile as u said but this was definitely not a good solution for 802.11b/g.

Matter of fact this antenna screwed up the signal instead of helping to get to far distances.

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octel says:

June 8, 2010 at 11:53 pm

Now if only Clear WiMax could fix their terrible infrastructure problems!

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kabukicho2001 says:

June 9, 2010 at 7:58 am

Hi:Instead of using biquad it would be better to use othe antenna like yagi or stub loaded helix one.