Thursday, January 12, 2012

The Midnight WiFi Rider

I went out again tonight, to play with microwaves; you might call them WiFi. OK, so it wasn't midnight; I really needed a catchy title. Anyway, I drove up to a high point in town, which isn't all that high; and, I pointed the Ubiquiti Nanostation LOCO down Conway Avenue in Mission, Texas just to see what networks I could hit.

As an aside, you can set Ubiquiti radios to "any" SSID, which, as the name implies, connects your radio to any open SSID it finds. Of course, there is more to it than that; the radios do not come with setup destructions, so there are plenty of things to figure out the hard way.

Chimney Park

Going back to my signal checking, I was able to see Chimney Park North and Chimney Park South, which are about 5 km away. I did not have a very clear line of sight other than what a road without traffic can provide. The elevation drops about 20 feet between where I was and Chimney Park.

There is another RV park that is about 1 or 2 km closer, Oleander Acres. I was able to occasionally see their network; but, it was much weaker, which is understandable. Oleander Acres does not have a clear line of sight up Conway. They are off to one side of Conway, surrounded by trees, and blocked by buildings and a highway bridge. Whereas, Chimney Park had nothing but open road between them and me.

I could see them; but, I could not connect. I am certain this is because their radios are omnidirectional access points. Perhaps it would work under ideal conditions; but these were not.

The Chamber

I then drove to the parking lot behind the Rotary Park, which I think is called the Leo Peña Placita these days. From there, my objective was to connect to the Greater Mission Chamber of Commerce public WiFi. There is no elevation change, the routers transmit at 400 mW from inside the building. Even so, I was able to connect from 250 meters away. The speed was not all that great (30 kbps to 300kbps); nor was it a reliable connection. It would flake out on occasion.

In the past, I had tried that link with a mesh router in between the park and the Chamber to act as a repeater. I got good speeds; but, the connection could get flaky at times too. Without a high gain radio, the connection simply isn't possible.

For the Record

I don't like the metric system. I'm quoting km and meters even though I can't estimate what they are, mentally. The only reason I'm using them is for the sake of calculating stuff. Metric is Measurement for Dummies. I've got enough going on that I don't want to fuss too much with conversions; therefore, metric.

What Could Be Done Differently

Even though my results were not amazing; they were rather exciting considering the limitations. Placing the radio on the dashboard of my old minivan was not the greatest location. It does not even bother to account for the Fresnel Zone and Earth curvature.

Obviously, a more definite line of sight would have helped. In the Chimney Park instance, having a pole would have helped. In the Chamber instance, a pole on my end and an external antenna on the other end would have really helped.

Given the limitations of these "quick and dirty" experiments, I'm not bummed out. Now that I know that my Ubiquiti Nanostation LOCO can likely achieve 15 km links under ideal conditions, I can start attempting to achieve those conditions. Yes, 5 km is not 15 km; however, that was 5 km under crappy conditions. The next step is to decrap the conditions.

How I Can Improve Results

  • I can get a higher gain radio for testing. Instead of the Ubiquity Nanostation LOCO, I should get the larger Nanostation. 
  • More elevation. Ground level simply does not work well with long distance radio communications. I'm going to need to raise my devices above rooftops and tree canopies. 
  • Better equipment. The "base stations" used in these tests are not designed for long distance links. They are designed for short-distance omnidirectional links. More directional equipment would improve the connections. 
That's it for now. Once I get past that, I can start tweaking some more to improve upon those results. 
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