line of site - how much of the tower needs to be visible?

I'm hoping to get wireless internet shortly (can't get dsl or cable).
The transmitting tower is maybe 2 - 3 miles away and when I look out
an upstairs window I can see the red light on the top of the tower -
everything below that is blocked by a building. Since the antenna
that *I* would need would be quite a bit higher than where I look out
this upstairs window (presumably higher than the peak of my roof) then
more of the transmitting tower would be visible if I were look at it
from the top of the antennae. So what I want to know is exactly how
much of the transmitting tower do I need to be able to see, in order
to get a good enough signal to get the wireless internet?

The Bean <(E-Mail Removed)> writes:

> I'm hoping to get wireless internet shortly (can't get dsl or cable).
> The transmitting tower is maybe 2 - 3 miles away and when I look out
> an upstairs window I can see the red light on the top of the tower -
> everything below that is blocked by a building. Since the antenna
> that *I* would need would be quite a bit higher than where I look out
> this upstairs window (presumably higher than the peak of my roof) then
> more of the transmitting tower would be visible if I were look at it
> from the top of the antennae. So what I want to know is exactly how
> much of the transmitting tower do I need to be able to see, in order
> to get a good enough signal to get the wireless internet?

That would depend strongly on where on that tower the antenna is
located. Towers typically host a multitude of antennae these days.

BEst Regards,
--
Todd H.
http://www.toddh.net/

In article <(E-Mail Removed)>,
The Bean <(E-Mail Removed)> wrote:
:I'm hoping to get wireless internet shortly (can't get dsl or cable).
:The transmitting tower is maybe 2 - 3 miles away and when I look out
:an upstairs window I can see the red light on the top of the tower -
:everything below that is blocked by a building. Since the antenna
:that *I* would need would be quite a bit higher than where I look out
:this upstairs window (presumably higher than the peak of my roof) then
:more of the transmitting tower would be visible if I were look at it
:from the top of the antennae. So what I want to know is exactly how
:much of the transmitting tower do I need to be able to see, in order
:to get a good enough signal to get the wireless internet?

You are likely going to suffer from fresnel effects. Please see the
information and calculator at
http://www.zytrax.com/tech/wireless/fresnel.htm
(or other places, I imagine.)

--
"There are three kinds of lies: lies, damn lies, and statistics."
-- not Twain, perhaps Disraeli, first quoted by Leonard Courtney

In article <(E-Mail Removed)>,
The Bean <(E-Mail Removed)> wrote:
:I'm hoping to get wireless internet shortly (can't get dsl or cable).
:The transmitting tower is maybe 2 - 3 miles away and when I look out
:an upstairs window I can see the red light on the top of the tower -
:everything below that is blocked by a building. Since the antenna
:that *I* would need would be quite a bit higher than where I look out
:this upstairs window (presumably higher than the peak of my roof) then
:more of the transmitting tower would be visible if I were look at it
:from the top of the antennae. So what I want to know is exactly how
:much of the transmitting tower do I need to be able to see, in order
:to get a good enough signal to get the wireless internet?

To within the accuracy of the information you have told us:
10 feet.

But if the blocking building is half-way instead of very near
either you or the other building, then you'll need 33 feet clear
sight.


--
'ignorandus (Latin): "deserving not to be known"'
-- Journal of Self-Referentialism

>To within the accuracy of the information you have told us:
> 10 feet.
>
>But if the blocking building is half-way instead of very near
>either you or the other building, then you'll need 33 feet clear
>sight.


The offending building is across the road from me, and down a long
laneway.

The upstairs window I was looking out of is in the middle point of my
house - if I go outside and stand next to the house, I can see a lot
more of the tower, as then the building is no longer in the way.

The Bean wrote:

> I'm hoping to get wireless internet shortly (can't get dsl or cable).
> The transmitting tower is maybe 2 - 3 miles away and when I look out
> an upstairs window I can see the red light on the top of the tower -
> everything below that is blocked by a building. Since the antenna
> that *I* would need would be quite a bit higher than where I look out
> this upstairs window (presumably higher than the peak of my roof) then
> more of the transmitting tower would be visible if I were look at it
> from the top of the antennae. So what I want to know is exactly how
> much of the transmitting tower do I need to be able to see, in order
> to get a good enough signal to get the wireless internet?

Get the wireless company to come do a site survey. From my experience,
I'd say you have a 80-90% chance of having a usable signal if there's
not much RF interference in the area. All the damn calculators in the
world can't explain why sometimes good line-of-site links don't work and
why links that break the rules *do* work. I've run into a lot more links
that shouldn't work that do than those that should work and won't.

Rôgêr <(E-Mail Removed)> wrote in message news:<or2dneFijbgvaG2iRVn-(E-Mail Removed)>...
> The Bean wrote:
>
> > I'm hoping to get wireless internet shortly (can't get dsl or cable).
> > The transmitting tower is maybe 2 - 3 miles away and when I look out
> > an upstairs window I can see the red light on the top of the tower -
> > everything below that is blocked by a building. Since the antenna
> > that *I* would need would be quite a bit higher than where I look out
> > this upstairs window (presumably higher than the peak of my roof) then
> > more of the transmitting tower would be visible if I were look at it
> > from the top of the antennae. So what I want to know is exactly how
> > much of the transmitting tower do I need to be able to see, in order
> > to get a good enough signal to get the wireless internet?
>
> Get the wireless company to come do a site survey. From my experience,
> I'd say you have a 80-90% chance of having a usable signal if there's
> not much RF interference in the area. All the damn calculators in the
> world can't explain why sometimes good line-of-site links don't work and
> why links that break the rules *do* work. I've run into a lot more links
> that shouldn't work that do than those that should work and won't.

The Bean:

I run a wireless ISP, and the equipment that we use does require line
of site. A firmware upgrade that I performed over the summer allowed
a headset to be plugged into the customer CPE and it exhibited audible
tones as you got stronger and stronger signal strength from the
transmitters on the tower. Unfortuately, my house does not have line
of site to the tower. There are trees in my back yard, and in my
neighbors yard across the street. Both block direct line of site to
the tower. However, I can see the tower directly to the left of ours.
For the hell of it, we got up on the roof and used the headset, and
we are able to get good signal. We are going through two sets of
trees. My advice, give it a try. Going through two sets of trees at
5Ghz, and getting 1.3Mbps throughput from a T1 is pretty damn good in
my opinion.

The Bean <(E-Mail Removed)> wrote:
> I'm hoping to get wireless internet shortly (can't get dsl or cable).
> The transmitting tower is maybe 2 - 3 miles away and when I look out

Three things come to mind:
1- try it. if you can get a laptop configured for the wireless connection,
wander around, including the roof.

2 - A reflector... a flat panel mounted on a nearby rooftop might
reflect enough signal for you to use. Lots of miscellaneous links and
good reading at http://www.freeantennas.com

3 - An active repeater, maybe in a nearby house, serving both them
and you for some mutually acceptable arrangement. David makes some
rather impressive antennas, and here uses a repeater for this link.
http://www.nodomainname.co.uk/Equati..._broadband.htm

The wireless provider may be prepared to do one or more of the above.

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8-122.5