Wi-Fi Antennas On the Cheap [802.11 Wireless]

It should be noted right off that I intend to research information regarding unconventional wireless networking use. You probably won’t find much here that’ll help with day-to-day wireless networking. Unless, of course, you’re desperate and don’t care that your setup looks ridiculous.

Probably one of the most popular things I’ve run across when looking into wi-Fi antennas is what’s called “WOKTENNA” or “WIFRY.” Admittedly, these names aren’t used as often as the concepts that are derived from them, but I think the names are funny, and you should too.

The idea is to use any metallic parabolic device (think about what you have in your kitchen right now that fits this bill) and to place a wireless USB adapter at the focal point of the selected parabola. Its been found that Asian cookware, like various types of WOK cookware work very well for this purpose. Here is a site that shows a number of examples when people combine USB WiFi adapoters with DIY antennas to make a “poor man’s wifi,” including several variations of the WOKTENNA idea.

Another cheap option is the parabolic reflector antenna. The one I used is called the Windsurfer; a template is available at freeantennas.com. The site claims that a 1:1 scale of the template will net you about 9dbi of gain, double the size and you’ll see 12dbi of gain.

But, how do the cheapies compare to the “proper” devices available for increasing gain?

Using a stock Fonera (from FON) version 1 wireless access point with DD-WRT firmware I attached various antennas and performed simple signal trials using a laptop and Netstumler. Below, you can see a screencap of Netstumbler’s output. The first section on the left was just some testing before running the trials. The stock Fonera antenna provides a mere 1.5dbi of gain, and at approximately 111 meters, gets a signal to noice ratio of -70 to -60 dBm. A large 5dbi omni-directional antenna attached to the Fonera provides a solid -60dBm rating at 111 meters. The same antenna with a Windsurfer parabolic reflector provides slightly more gain. Using a 10dbi directional panel antenna — the “proper” way to direct wireless signals — performs equally with the 5dbi omni-antenna with the Windsurfer attatched.

WiFi Signal Stregnths of various antenna methods. (Click to view full image)

Approx. range of trials. (Click to view larger) Tests were performed at ground level, folliage was not an issue.

The most surprising result, however, is the result seen with the stock 1.5dbi Fonera antenna and the Windsurfer parabolic reflector. As Netstumbler reports it, this arrangement provides just as much gain, even a pinch more, than all previous antenna combinations, including the 10dbi directional panel and the much larger 5dbi omni-directional antenna!

So, if you’re trying to get a signal outdoors or to the other side of your home, try throwing a parabolic reflector antenna on your current setup before laying down any cash on inferior solutions!

Coming soon… additional tests with the same antennas at a larger distance, new antennas, and a dual-antenna setup (Linksys WRT-style).

Update to WiFi Map & Other Updates

I’ve made a sizable update to the WiFi Scan / Wardriving map adding nearly 1000 new points to the map from areas in Southern California. Though, for some reason, the new points are not showing on the web maps, but show when the KML file is loaded directly into Google Earth. I would figure out what the problem is, but, meh.

Secondly… I think I was going to say something about how I’m really digging WordPress 2.7 and its built-in plugin updating and auto-install features. So yeah, I really like WP 2.7′s plugin updating and auto install feature.

Third, I’ve recently become engaged. I guess others would use that as an excuse as to why they are spending less time with online endevours. I’m not. I haven’t spent too much time on this site before the engagement, so, no excuses from me you will hear. However, you will be delighted (but probably “meh”) to know that I have not spared my engagement from the nuances of nerdom. I am currently building a site to centralize wedding details, photos, and house a blog where my dearest and I will share our adventures with family and friends. The site will also have a method to accept RSVPs from guests. I thought that idea would get shot down right quick, because it’s “not how it’s done.” But, to my surprise, she was excited about the prospect of saving the postage by not sending return cards to our tech-savvy friends and family (the techno-phobic will still get the tradtional reply cards).

So anywho, that’s some of what’s going on over here. How about over there?

A Personal Project: WiFi Scan & War Driving

I’ve created  a page that displays an interactive Google Maps mashup of wireless access points with dynamic pin colors and detailed information including geographical coordinates, type of encryption (if any), and signal strength. Below the map is a link to download the KML file for use in Google Earth. Most, if not all, of the points have been captured during wardriving (though, I may have been a passenger in the vehicle, or walking, or riding a bike), with an Android-powered smartphone using WiFi Scan.

As you’ll see most of the points are located in Turlock, California, USA. Other points have been captured while wardriving in Merced, and Dublin, California and various paths throughout Stanislaus, Merced, San Joaquin, and Alameda County.

Wardriving with Wifi Scan in California and beyond (at some point)