June 17th, 2005


(no subject)

Today I am pleased by simple but non-obvious solutions to things.

For example, in poking around researching wireless networks, I discovered that, apparently, the true data rates of wireless networks are as follows:
  • Pure 802.11g network with no support for 802.11b does ~27Mbps.
  • 802.11g network with support for 802.11b but no 802.11b clients does ~18Mbps.
  • 802.11g network with active 802.11b clients does ~9Mbps for the 802.11g clients.
  • 802.11b clients always get ~6Mbps.
Obviously this is pretty daft for 802.11g clients to be dragged down to one third of the speed of which they are capable, just because of one 802.11b client on the network. But going incompatible and forcing people to upgrade isn't nice. The delightful simple but non-obvious solution: an access point which has two wireless cards, one doing 802.11b the other doing 802.11g, linked together into a single network. Instant maximum speed for all, at a fairly negligible cost.

Another geeky wireless example - I was looking for wireless devices that support external antennae, for potential community wireless things at some point in the future. Neighbourhoods sharing internet access seems like a good idea to me. The only cards that seem to properly support external antennae are PCI cards, the worst choice for setting up for other people since they require opening up your computer. Nearly all the USB wireless connectors I could find are just tiny sticks that will project from the back of the PC's case, with no antenna connector. The delightful simple but non-obvious solution: USB extension cables. The USB device itself becomes the external antenna. Apparently, standard external antenna cabling generally adds ~0.5dB loss per metre of cable and ~1dB loss per connector (for comparison, adding a small DIY dish to an aerial adds ~21dB), whereas USB extension cables will be effectively lossless within reason (and can even have quite cheap repeater hubs added to extend "within reason"), so this option is in many cases superior to a proper external antenna. (I later found a USB adapter that incorporates a proper directional antenna, though USB extension cables still appear to be the way to successfully distance the aerial from the machine.)

Tell me delightfully simple but non-obvious solutions that you have encountered. Other than duct tape. We all know about duct tape.