Using wireless to get a fast connection where none exists

[Charles Steinkuehler]

Dustin Decker wrote:
> Charles Steinkuehler (charles at steinkuehler.net) wrote:
> [snip]
>>When a radio signal hits something like a building or tree, it gets
>>attenuated and possibly dispersed (ie: weakened), not "swallowed up".
>>
>>Probably the best way to get a 'real-world feel' for what happens is to
>>compare wireless links to cell-phones (especially the more modern
>>digital phones, which use somewhat similar frequencies).  They'll work
>>through walls, inside metal buildings, etc, but the link quality will go
>>to hell, and if it gets bad enough, they just won't work at all.
> [snip]
> 
> Just out of curiosity, anyone tried to make their own "pringles can" antenna or the
> like?  Saw this a while back on ThinkGeek, and thought it might be worth a shot
> if/when I find myself in need of a good antenna - anyone had a go with one of these
> yet?
> http://www.thinkgeek.com/computing/accessories/666e/

I didn't try the pringles can (it's really not a good size for 
2.4G...see the spreadsheet below), but I did try a waveguide 'can-tenna' 
(I used a can identical in size to the hunts pasta/spagetti-sauce can), 
a D-Link flat panel antenna (DWL-R60AT), and a passive reflector:

Cantenna info:
http://www.turnpoint.net/wireless/antennas/hunts.html
http://www.concentrate.com.au/misc/circular_waveguide_optimise.xls

D-Link Antenna:
http://www.d-link.com/products/?pid=57

Passive Reflector:
http://www.freeantennas.com/
http://www.freeantennas.com/projects/template/parabolic.pdf

All had roughly similar results, with terrible packet loss until I 
forced the DWL-900AP+'s into 1/2/5.5/11 MBit mode (ie: disabled the 
high-speed 22 MBit mode).  That's one reason I strongly suspect 
multipath was a big part of my problem...there should have been a 
substantial difference in gain between these various antennas.

I'm currently running with no extra antenna (just the stock dipole) on 
one end of the link, and a parabolic reflector made from the pdf pattern 
above on the other end.  As mentioned, the link travels through two 
complete houses (and exterior walls of two other houses), and has been 
working solidly for about a year.  I haven't done lots of testing of the 
link bandwidth, but my ping flood packet loss across the link fell to 
<1% once I switched out of 'high-speed' mode, and even if I'm running at 
1 MBit/s with lots of overhead, it's faster than the 384K link I'm 
sharing with the neighbors.

I'll probably do some speed tests when my service gets upgraded to 
1MBit+ (should happen as soon as Birch gets me an install date for their 
new combo voice/data service!).

-- 
Charles Steinkuehler
charles at steinkuehler.net