(E-Mail Removed) hath wroth:
>The amp is to contact the access point on the far end of the valley (2
>miles away, which also has an amp and directional antenna to this
>area.).
So, you're going to be legally limited to a 6dBi antenna on this link.
Such antennas are not very directional. If you're also operating a
wireless system for clients in the same band, you're going to create
substantial inteference.
Howeve, you mention "directional" antenna. You're still limited to
6dBi gain whether omni or directional with 1 watt out. See FCC
15.247(?) for the confusing rules and regs. If you're going to use a
higher gain antenna, you're going to go well over the FCC limit.
Looking through your list, I see a 14dBi panel antenna which I presume
is the corresponding link antenna. That's well over the limit and
totally illegal. Were you to setup such a contrivance in my backyard,
I would instantly report you to the FCC enforcement bureau as a gross
polluter of the airwaves.
So, lets see what can be done without the power amplifier (which is
incidentally the most expensive item on your shopping list). Start at
for link calculations:
|
http://en.wikibooks.org/wiki/FAQ_for...k_Calculations
I'll make a few guesses as to your hardware and setup. Please correct
as required.
TX power = +15dBm
TX coax loss = 4dB (3ft LMR-240 plus a mess of connectors)
TX ant gain = +14dBi
Distance = 2 miles
RX ant gain = +14dBi
RX coax loss = 4dB (same at other end)
RX sens = -84dBm (at 12Mbits/sec)
Fade margin = unknown
Plugging into:
http://www.terabeam.com/support/calculations/som.php
I get a fade margin of 8 dB which will not work. Changing the
antennas to 24dBi barbeque grill antennas, this becomes a fade margin
of 29dB which is well above the recommended 20dB minimum and will work
just fine.
Loose the amplifiers and get some bigger antenna.
>That's the reason for the amp, to make the distance to the other access
>point. and to quite honestly, burn through the trees.
Oh, you have trees? How thick, what type, how many? Such things can
be calculated (or guessed). Your 1 watt amplifier will yield a gain
of about 15dB over the un-amplified output of about 15dBm. A MUCH
cheaper dish antenna will yield 24dBi. You also have the benifits of
having a much narrower beamwidth so that you pollute the valley. Also,
the rules for point to point are quite different. With a 24dBi dish,
you can legally run 24dBm power output maximum (about 300mw).
>The line of
>sight distance to the other access point is very close to the horizon
>(more trees).
Well, that's another problem. If you're that close to the ground, the
Fresnel zone clearance will be a major problem:
http://www.terabeam.com/support/calc...esnel-zone.php
At 2 miles, you have to have 26ft of clearance around the alleged line
of sight.
>Initial tests,
Initial test using what equipment?
> show the connection can be made if both sides of the
>connection are running at 200 mw. But we get -89-90 signal. Not
>enough for a stable connection.
I suggest you look into 900MHz equipment that is made for going
through trees:
http://www.wavewireless.com/SPEEDAccess_text.html
http://www.avalanwireless.com
--
Jeff Liebermann
(E-Mail Removed)
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558