Nelson's log

Fixed wireless Internet: Cambium, Ubiquiti

I don’t believe in wireless communications. Too spooky. Also too unreliable, and slow. And 2.4GHz wifi is particularly bad in San Francisco, between the crowding, the lack of distinct channels in 802.11a/b/g, and the faraday cages surrounding all our lathe-and-plaster rooms.

But in Grass Valley wireless is the only option. AT&T and Comcast refuse to provide wired service to rural homes and PUC and the FCC are not regulating their monopolies effectively. My ISP is SmarterBroadband, a wireless ISP that works by establishing fixed wireless links from house to house to regional distribution point to central office and then down to fast fiber backhaul. It works surprisingly well and reliably, the main limiting factor has been speeds and the challenges of getting clear line-of-sight in a hilly area covered with trees.

My link for the last couple of years has been a 900 MHz link through oak trees to a house 1.4 miles north of me. The key thing about 900 MHz is it works OK through tree cover, something higher frequencies has a harder time with. Cambium Networks hardware running Canopy, which I think dates back to the old Motorola Canopy days. It’s been pretty reliable; the only time my point to point link has failed has been in heavy snow, and then only because snow accumulated on the antenna. Also low latency (20ms?) and low jitter. The problem has been speed. The max link speed is 2600kbits/s, and the product they sell me only bursts that fast before throttling me down to 1000kbit/s. That’s 300 megabytes / hour, and it sucks.

Yesterday they upgraded me. Sent a guy 70 feet up a tree with a Cambium ePMP 1000, a 5Ghz antenna. Pointed at the same house but that far up we’re above the trees, clear line of sight. I’m told the link is good to 25 Mbit/s but I’m being sold 12/2 Mbps. Which is still pretty great and I’m grateful for the upgrade. I’m surprised how cheap the antennas are. They offered me an upgrade for a very low cost, and it looks like you can buy your own antenna for about $140. Of course you need the service!

In addition to 900MHz and 5GHz my ISP sells two other types of wireless links. There’s a 2.4GHz product they mostly don’t sell any more. It also requires clear line of sight, but is slower than 5GHz. And they have a new 3.4GHz product they label “4G”, I think because it’s based on cellular technology. It’s pretty fast too (their product offers 70% the bandwidth of 5GHz) and is able to handle a little multipath, so works with a small amount of tree cover. Didn’t work at my house though, and once we were committed to going up a tree we might as well use the 5GHz gear.

The other half of the problem I have now is getting the Internet connection from the tree 200′ from my house inside. I’m intending to run cable, but that may get complicated depending on the status of existing conduits and the challenge of trenching. Right now I have a shitty old Linksys WRT54GL sitting outside and it works surprisingly well. That’s making me think I should try a wireless link instead, even though I don’t believe in wireless.

I asked on Metafilter and got a clear consensus answer on the product I need: a Ubiquiti Nanostation M. These are consumer grade point to point wireless links. There’s a variety of frequencies and antenna sizes. They’re rated for 5+ miles so are way overkill for my 200 ft needs. But then I can probably use the tiny 9″ x 3″ antennas and be done with it. It looks like I can get a pair for about $150. Need mounting hardware and a bit of wiring work at both ends to install it right, but still that’s got to be cheaper than digging a trench.

The big question is how reliable this kind of link is. Reports are promising! I’m also curious to know what’s going on at a protocol level. They call their protocol “airMAX” which is apparently not 802.11, it’s some TDMA thing. OK, I’m fine with proprietary. But then does the link work as an ethernet bridge? Or is it working at an IP level and messing with my packets? More to learn.

Wireless; maybe not as scary as I have believed! Still nothing beats a clean run of Cat5e. Except a pickup truck full of hard drives, of course.

Update: Ubiquiti answered a tweet I made asking for advice, with a suggestion to use the Nanostation locoM5 and a suggested wireless bridge configuration. That sure makes it easy!