by Sorry if this is not the forum for this - let me know where to ask if so.
I work for a small ISP and we did a deal with a customer to sign them up
to connect to us via "wireless lan". In short, Aironet's stuff. Basically
it's 2.4Ghz digital
spread spectrum signal.
At any rate, I can handle the networking part of it fine - the question I
have is about
the antenna.
I know that the rule of thumb for line of sight signals like this is to
get the antenna as high as possible - above the tree line of course - and we
are in an industrial park and have permission from the landlord to build a
tower, etc. The building is 20 feet high and I figure to go at least 50
feet.
A couple of things though I have questions on:
1) After calling the local government it appears that we need to get a
conditional use permit. They say that this is usually a *** stamp
process for an industrial park (unlike a residentail area), and also told me
that I was somewhat in a grey area as to needing it anyway, since it didn't
sound like that large an installation. What I'm wondering is that if a 50
foot tower is considered "small" perhaps I should get the permit for 100
feet just in case we need the tower to get higher. Of course, the higher
the tower on a permit request, the more likely it might attract attention.
Any suggestions here? My boss was of the opinion we should just***the
permits and put up the tower and see if someone ***es about it. I'm a bit
more cautious as I'm concerned that if we do that we might be forced to take
it down.
2) There are 3 different types of antennas available with this gear - a
window patch (that is obviously intended for the customer end) a parabolic
dish, and a Yagi. The salesperson at Aironet seemed to imply that a Yagi
was omnidirectional - which would imply that all we would need to do is put
up a Yagi and feed anyone in the 5-10 mile radius.
Since then after talking with several tower contractors I've been informed
that a Yagi is very directional just like a dish. Now I'm wondering if we
are going to eventually need to put up multiple antennas on this tower as we
get more customers scattered around us. Would it be better to put multiple
dishes up pointed in different directions, or multiple Yagi's? This would
affect the tower construction, as dishes have greater wind loading, are
harder to hide, etc.
Really, what's the big difference between them (other than obvious
construction issues) is one more efficient than the other?
3) The height of this thing is sure to become an issue - obviously a higher
tower is going to cost more and the owner is kind of a penny pincher. Of
course it would be disasterous to sink $10K into this and have it not work
because of trees in the way. I get mixed messages on this - some people say
trees won't block the signal, others say they will. This obviously also
will affect how tall a permit we need to get.
I'm sure that the landlord will also probably start arguing about this if we
make it pretty tall - fortunately we forced an antenna permit into the last
lease renegotiation, but it would help if I could have some testimonials or
be pointed to some resources that would be more definite as to if trees
would block a signal of this frequency.
Thanks!
Ted