Original URL: http://www.theregister.co.uk/2013/08/22/scottish_nonnotspot_extended/

Reg hack battles Margaret Thatcher's ghost to bring broadband to the Highlands

Swat the Not Spot

By Bill Ray

Posted in Networks, 22nd August 2013 09:02 GMT

Scottish broadband remains an elusive dream for many, despite the money being poured into BT's coffers, but pigeonhole a Reg reporter and you might just get lucky.

That's what Ronny did. He grabbed your correspondent at a ward meeting where reps from Community Broadband Scotland were polling householders for their opinions – to be held in reserve until 2016, when the community broadband kickstarter fund could do something about them – while presenters and audience alike blamed Margaret Thatcher and your humble correspondent told everyone to get off their arses and build a solution, which is what Ronny wanted to do.

I'd been invited to speak about how I brought broadband to my own home, a process which involved digging up a sheep field, braving carnivorous plants, falling out with several neighbours and, eventually, maintaining the 5Mb/sec connection I enjoy today.

The Ward Forum, a community talking shop, had invited Community Broadband Scotland along to explain that, come 2016, CBS would be able to support community-driven efforts with £5m in government cash. It can't do anything yet, the reps explained, as BT is still deciding how to spend the hundreds of millions of pounds it has been awarded by the Scottish government, and one wouldn't want to overlap.

This being Scotland, speakers were repeatedly interrupted by demands that BT be re-nationalised, despite that probably being beyond the power of the quango. A later presenter, who has been busy polling local opinion as recommended, even had a slide explaining how it was all Thatcher's fault for selling off BT in the first place, to the delight of the assembled.

My own argument was that anyone determined to get broadband could get broadband, and not by writing letters to BT or polling local opinions. Satellite is a lot better than it used to be (£150 install, £25 a month for 20Mb/sec) if one can tolerate the latency, and in Wales Exwavia has been spending the Welsh Assembly's thousand-pound grants on cheap microwave gear to link up homes, so it can be done.

But in Scotland, and England, the money is largely being handed to BT, so anyone wanting broadband now will have to build it for themselves.

When is a huge warehouse filled with single malt actually a problem? Read on...

Ronny is a typical Highland not-spotter: he runs a bed and breakfast on the East coast and takes bookings over the internet, but to see those bookings he has to get into his car and drive seven miles (11km) to the nearest public library with its internet connection. Broadband isn't a luxury, it's an essential – which is why he approached me at the end of the meeting to see if line of sight was a possibility.

A few days later he turned up armed with a telescope and tripod to establish if we had visual contact. Sadly the Glenmorangie warehouse lies between us, blocking ground-level contact, but from the top of my roof (where tripod and telescope are of little use) there appeared to be a line to his chimney pot – and, Fresnel-zone permitting, a narrow line of sight is all that one needs.

The Fresnel Zone is a blimp-shaped region within which radio signals propagate. A microwave signal isn't straight like a laser beam but gets fat around the middle. Trees, buildings and other clutter can interfere even when line of sight exists, and this zone of possible interference is called the Fresnel Zone after the physicist who calculated it.

A blimp-shaped

The Fresnel Zone, as shown by Wikipedia

Having said that, the microwave kit we're using tops out at 150Mb/sec, and the ADSL to which it eventually connects (at Claire's house) is only 5.5Mb/sec, so we can afford to lose most of the signal in transit.

The kit came from the nice chaps at WiFi-Stock who sell Ubiquiti AirGrid Airmax transceivers at £51.32 a pop. That's a very good price, though slightly less good when one adds the £35.01 for delivery (Highland surcharge) and the £5.51 for the privilege of paying with a credit card.

Chuck in the VAT and the whole bundle comes in at £171.79, but the kit itself is a joy to behold.

I've written about the AirMax before; how the lights on the side make alignment so much easier and the web interface lets even a complete idiot configure the radio link for optimal performance and regulatory compliance (if one wishes).

My Ofcom licence – £50 a year and required for my first microwave link to Claire's house – covers me for any number of points, so I just registered these new transceivers using Ofcom's website and everything is legal and above board.

The station list

The AirMax radios use PoE (Power over Ethernet) and come with an injector and a mains adapter in a separate box. The radio now also comes with a USB injector, which turned out to be unexpectedly important.

First task was bolting another antenna to the outside of my house, on the opposite gable from the existing link, which proved easy enough. A cable from there runs into the loft though I did discover that the weatherproofing seal where the cable enters the antenna is blocked by one of the bolts, so some balancing atop a roof ladder with a Dremel could have been avoided with better planning.

The antenna at my end

Equally, a glue gun was used to secure the sticking-up cable ties with which I hope to discourage birds perching. On the last antenna I strapped cable ties round and they worked great until the birds pushed them over, and since then the dish has been a welcome perch for our feathered friends and the radio is coated in guano.

So far this has had no impact on the signal, but I suspect it's no good thing and hope that a drop of glue on each cable tie will hold them in place. This too would have been much easier on the ground, but was done in the air (incredibly at both ends, as though I failed to learn the first time).

The ladders

Wireless Distribution System? More like Wacky Doesn't Signify much acronym

My roof ladder isn't quite long enough for Ronny's roof, and we considered ordering another section but instead managed to bodge it.

Our only hiccup came when we plugged in the radio at Ronny's end, and it was completely dead – not a flicker. Nipping back to my place we quickly established that the transformer for the PoE injector was faulty and considered boxing up the whole thing for dispatch back to WiFi-Stock before remembering the USB injector in the AirMax box.


Power into the Ethernet from any USB source, every home should have one

The ubiquity of USB as a power standard meant a spare transformer was quickly located, and the radio instantly sparked up and started looking for a connection.

From there we just pointed the fitting in roughly the right direction and both radios happily reported everything working just fine.

Sadly it wasn't. IP worked, but DHCP – the device configuration which allows networked kit to communicate using IP – refused to function. The Airmax can operate as a Network Address Translation router, but I dislike NATs at the best of times and double-NATting is against my religion. Our DHCP server is, therefore, at Claire's house and I wanted it to allocate IP across all three properties.

Some internet searching revealed the Airmax needed changing to "Access WDS" before it would pass DHCP packets. WDS apparently stands for Wireless Distribution System and I remain unclear what the difference is, but I do know that one should first link "Access Point" and "Station" together and then switch both into "WDS" mode, after which the link works perfectly.

(The fact that my link to Claire's house is not using WDS mode, and happily carries DHCP packets, is an anomaly I'm choosing to ignore.)

At first flush we got the full 150Mb/sec between my house and the B&B, but once the "Obey Regulatory Rules" got ticked (reducing the signal from 20dBm to 1) the speed stabilised around 6.5Mb/sec. We could probably improve that with better alignment, but there seems little reason to bother given the ADSL choke point.

The antenna at Ronny's end

That's the technical side out of the way, and for the moment that's all there is. Ronny isn't offering internet access to his guests, and his own consumption is minimal – just checking email and updating the website every now and then – so I'm happy with the couple of bottles of wine he's given in gratitude.

I could bill him for access, but that would get complicated as Zen Internet might get upset, and given The Register pays for my broadband they too would have a legitimate objection. So for the foreseeable future it's a true community connection, sharing something I currently have in abundance. How long that can last I'm not sure but for the moment it's one less not-spot in the Highlands and that's got to be a good thing ... and at least Ronny isn't driving 14 miles in a day just to read his email. ®