Jeff Liebermann wrote:
On Wed, 16 Dec 2009 21:25:34 -0600, tom wrote:

What "vector"? The beamwidth width was 120 degrees for Go Networks
and 60 degress for Vivato. That's not a beam. That's a barn door.
That nonsense got me rather irate when the FCC concluded that an
overpowerful alligator, with beam steering, will somehow cause less
interference than a sector antenna system.

Go Networks was one of the later vendors to hop on the alligator
bandwagon:
http://wifinetnews.com/archives/2006/04/go_networks_slips_veil_on_cellularmesh_metro_wi-fi.html
They picked up the fumble after Vivato dropped the ball.
http://en.wikipedia.org/wiki/Vivato
To add insult to injury, Go Networks somehow convinced the FCC that
120 degree wide steerable "beams" qualified for the higher power. I
could do better with common sector antennas. At least Vivato used 60
degree beams, which was marginally better. As I recall, their
literature had an illustrators imaginative drawing showing what might
be hundreds of beams with what appeared to be about 5 degree
beamwidth. The illustration also showed the steerable antenna hung on
a wall, thus eliminating half the "beams".

What I saw with the one Vivato 2210 controller I played with was that
the usable range was about the same as a lower powered omni or panel
system because of the alligator effect. The AP was deaf. So was
management.

Incidentally, one local Muni Wi-Fi network turned DOWN their mesh
nodes TX power when they were finally convinced that they were
creating almost all of their own interference. Things worked much
better when the access points and repeaters used approximately the
same tx power as the client radios.


Absolutely right on the power.

I was referring to the panel antennas, not the pole mount units, but
your point is well made. I didn't mean to imply that it was a good
solution.

I modeled the 4 vertical pole mount unit and it's nothing great. At
least the panel versions ended up with some front to back.

Unfortunately, few muni systems seem to use sector antennas. Probably
because you can lose money just as easily with a cheap system as an
expensive one.

I am just glad that I am no longer near the WiFi biz.

tom
K0TAR