…for they shatter the illusions of faithful happy Mac users like me that you “can just plug it in” and “boom, it works” and stuff like that. Well, it might be true that if you try to get two Genuine Apple AirPorts to talk to each other via WDS they work happily – though given that AirPort Utility frequently can’t even find the Express within 50cm of it, I doubt it. (Computers really need a “IT’S JUST THERE YOU BLASTED THING” button, to go with the “OH JUST RUDDY DO IT” one for every dialogue box.)

Getting an AirPort Express to talk to a Belkin router is, however, decidely not fun. And that’s a great shame given that the Express costs £70, but the Belkin is just £30 from Argos.

So after n hours of swearing, Googling, and therapeutic pints of perry in the Rose & Crown (now only 30 seconds from our new house – which I should blog some time, it’s much more exciting than this), we now, finally, have wifi in the barn (where the computers are) as well as the house (where the phone line is).

As ever, for the sake of any other poor unfortunates trying to do the same, here’s what finally worked. Our setup is a cheapy unbranded Chinese ADSL modem; an AirPort Express connected to it; and a Belkin G+ (aka F5D7231-4) in the next room, which provides enough of a boost for the signal to make its way to the barn via several very chunky 18th century stone walls.

To summarise, the changes that made the difference (as far as I can tell) were: giving absolutely everything an IP address in the same range; making sure that range was 192.168.2.x, which seems to be where the Belkin is happiest; preventing anything apart from the modem/router itself from distributing IP addresses via DHCP; and using wireless channel 1.

ADSL modem/router
IP address 192.168.2.1. DHCP pool 192.168.2.2 to 192.168.2.15. (I figured it was easier just to have one box distributing IP addresses.)

AirPort Express (connected to router via Ethernet cable)
Basic settings:
- Wireless tab set to ‘Participate in a WDS network’.
- Network name set to ‘My luvverly wireless network’ (well, not really, but you get the point).
- Channel 1. I initially tried it on 12. It didn’t work.
WDS settings:
- WDS main.
- MAC address of the Belkin added as a WDS remote.
Internet tab:
- Configure IPv4 manually.
- IP address 192.168.2.2.
- Subnet mask 255.255.255.0.
- Router address 192.168.2.1.
- DNS server 192.168.2.1.
- Connection sharing Off (Bridge Mode).

Belkin (in the next room, not connected to anything)
Use as access point: enabled, with IP address 192.168.2.254 (the default) and subnet mask 255.255.255.0. After a reboot, this disables half the functionality (a Good Thing), and you can log in at 192.168.2.254.
Channel 1 (as per above).
SSID ‘My luvverly wireless network’ (again, same as above).
Wireless bridging enabled.
Enable only specific access points: ticked, and the MAC address of the AirPort Express entered.

Security (update)
Oh, I was hoping you weren’t going to mention that. The AirPort and the Belkin won’t talk WPA to each other, sadly. They will, however, talk WEP 128-bit, with the usual caveat that the Belkin’s ASCII-to-WEP key algorithm is different from Apple’s. I took a 13-character Apple-style password, set it on the AirPort, then passed it through this WEP key generator and fed the resulting hex bytes into the Belkin.

Finally, kick each item several times, and have a large drink. Or two.

After all that, the client computers (I’ve tested three) should just work happily and get their settings via DHCP.

Matt Amos (who should blog more) has done a really cool visualisation of the editors used by OpenStreetMappers. Blue is Potlatch, red is JOSM, green is Merkaartor, and grey is everything else.

Really big disclaimer: this is based on the created_by tag, and JOSM and Potlatch treat this differently. JOSM sets the tag whenever it adds a new object: Potlatch sets it whenever it adds a new one or modifies an existing one. So there’ll be an inevitable bias towards Potlatch. (Potlatch’s behaviour is arguably more sensible but I’ll leave that for another time!) But despite all that – isn’t the big mass of blue pleasing to the eye? Well, I thought so.

See the full image here.

There has been some debate in the OpenStreetMap community about the exact provisions of the Open Database Licence.

Richard Weait has done a very good job explaining it in diagram form, but the exact nuances of the licence may still remain unclear to some. Therefore I hope the following illustrations will aptly yet concisely show the intricacies of licensing geodata, and the respective virtues of CC-BY-SA and the ODbL.

Thank you for your time.