As a former Canopy user, I would like to point out a couple of issues
not mentioned here.
1) Canopy is limited to vertical polarity in PTMP deployments. Trango
and many other systems can be deployed in horizontal polarity, pretty
much avoiding any Canopy in the area.
2) Canopy systems will be more robust in comparison to other systems
deployed at the same antenna gain and polarity, and they will also
coexist nicely with other Canopy systems if they are all running GPS
sync on the access points. HOWEVER, non-synced Canopy causes other
Canopy systems all kinds of problems, and other types of systems will
take a Canopy system down if the other system has higher gain and runs
on the same path. Canopy will run with 3db of signal to noise
separation, which is more robust than 802.11b for example which needs
5-6db - but that doesn't make it immune to noise. There are situations
where the poor antenna design of the Canopy ends up getting more noise
and will run worse than a better engineered 802.11b system.
It is easy to build a 2000lb elephant (legally, I will add) that will
kick the 500lb gorilla's butt. Been there, done that. I'm glad I don't
have to deal with Canopy any more.
Matt Larsen
[EMAIL PROTECTED]
Forrest W Christian wrote:
Richard Goodin wrote:
I have been planning my WISP for about a year, and have yet to begin
delivery of bandwidth to customers.
Since Canopy hasn't been mentioned yet, I'll mention it.
You really can't go wrong with a canopy installation. It works, even
in the presence of noise that would kill other systems. We swapped a
dying (due to interference) Trango system with a canopy system well
over a year ago and haven't looked back. As customers on our
existing 802.11b network have problems we just swap them to Canopy.
Some here will probably mention canopy's "abusive" spectrum use.
Yes, Motorola uses a very agressive modulation which both provides for
incredible interference robustness, but unfortunately doesn't play
very well with others. Systems with marginal link budget will fail
when put in the presence of a motorola radio. I have heard this
referred to as the 500 pound gorilla approach - I.E. where does a 500
pound gorilla set? Anywhere he wants to. I find it hard to see
this as a disavantage to the Canopy operator. After all this is
business, and you need to make decisions which improve your bottom line.
One more thing... you need to be very careful about FCC certification
of systems. Many of the systems which people put together themselves
are not legal in the eyes of the FCC. In short, buying a radio from
vendor A and pairing it with an antenna from vendor B may or may not
be legal, even if the EIRP limit is not exceeded. Plus, you will
have vendors (distributors mostly) which will lie to you about whether
or not a given pair is legal. Currently many WISP's are doing things
which are definitely not legal under the rules, and count on the FCC's
continued non-enforcement of the part-15 bands as part of their
business plan. As being an Amateur Radio operator and seeing what
happens when the FCC decides to actually pursue enforcement in a band,
I wouldn't want to tie my continued business survival to illegal
equipment.
-forrest
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