Technology & Gadgets

Long range wireless

I finally got the time to get together with my good buddy and former roommate, the fire chief of Sunshine, Steve Stratton, and set up a long range link between our houses. He has a T1 line (1.544 Mbps up and down) and I’ve been using my Motorola V551 GPRS for internet access for the past two weeks, which is pretty painful. I used my Mac via Bluetooth to serve up the GPRS connection to my other computers. The rate is 100 kpbs which is not half bad, but the latency is terrible (2-5 seconds), and it doesn’t deal well with multiple transactions.

I bought two LinkSys WAP54G access points, and two enclosed outdoor Yagi antennas (EnteraSys RoamAbout Point-to-Point Wireless: RBTES-BG-Y14M), and actually got the link working nearly flawlessly between our houses, which are over 2200′ apart, with trees partially obscuring the line of sight and energy envelope (big oblong) of the transmission (if both were not obscured, this link could go to 8 km). The link is pretty good, but not quite reliable enough for VOIP (I think the wind moving the trees is causing problems).

The antenna is on Steve’s deck, fastened to the railing using some paper wedges, and the access point is in a baggie on the deck (didn’t have enough antenna wire to put it inside).

This is the view of Steve’s house (the roof, circled in red) from my house out the window.

The other antenna is precariously perched on the window sill inside the house I’m renting.

They’re pointed ROUGHLY towards eachother, but not very exactly. The polarization appears critical, as rotating the antenna about it’s access kills the signal. It’s a very good thing the link worked the first time, as I have no signal strength metering on either access point, so everything is binary (link or no-link).

I added WEP 128 bit encryption so other folks couldn’t tune in (also MAC address control), but I have not yet hacked the firmware to boost transmit power (x4 is possible with these APs, as they use open source Linux, and many have hacked them).

Total cost of the setup: WAP54G ($60 x 2) + Antennas ($62×2) = $244. This is pretty good, because the antennas MSRP are over $280 each.

By Dave

He was born in Canada, but currently lives in Boulder, CO up in Boulder Heights.