Melbourne Wireless
Get into Wireless LAN anyway you can at wireless.org.au. I reside at node CIA. The view from the roof (important because 2.4GHz signals at < 100mW don't penetrate anything much) is good
Cantenna Testing
The results of the preliminary round of Cantenna testing
are available. This testing characterises the beam pattern of a Harris Coffee Tin used
as a circular waveguide.
The polar plot to the right summarises the results. Essentially, the device under test, a harris coffee can
of internal diameter 98mm, with a tuned 1/4 (28mm of copper instead of 31mm) wave stub was placed on a post
and rotated in an anechoic chamber. From about 8m away, a series of measurements of received signal power were
taken by a spectrum analyser. A signal generator was used to launch a constant 10dBm at 2.462 GHz (choice of
frequency is a long story, I'll try again at a lower frequency later) through a source at the device under test.
The directivity or gain of this cantenna is found to be between 6 and 7dBi.
I intend to make modifications and perform further testing to determine the improvement gained by adding an extra length of can to make it 5/4 guide wavelengths long; a choke; a spreader.
Network Architecture
I have done a considerable amount of thinking about feasible ways to construct a network architecture to provide some degree of mesh routing for the wireless community of Melbourne. There are slides to document the design thoughts (also in PPT format. Additional information can be found on the Routing / Addressing working group.