On 15 Jul 2005 07:18:53 -0700,
nurp@pbworld.com wrote:
>I am currently using a waverider EUM3000 and running into issues where
>I lose my signal on and off. I am having problems pin-pointing the
>items that are causing interferences.
How about some numbers?
Range to access point?
Type of antennas in use?
Length of coax run (if any)?
Approximate path profile (how bad is the line of sight ignoring the
trees)?
Extra credit... Exact lat-long and antenna height of both ends so I
can calculate the fade margin.
|
http://support.waverider.com/dmfiles...opTest_r2.pdf?
I wouldn't expect you to actually peform this test, but the calcs can
be done with sufficient information.
>When aligning my antenna I can achieve about 77+/- dbm but can never
>get it to stick/stay constantly. It will be working good but then
>numerous times throughout the day it drops in and out.
What makes you think it's interference and not multipath? I think
(not sure) that -77dBm is a fair signal stength. However, if it's
varying all over the place, my guess(tm) is that you have either more
than one path between your EUM and the CCU, or that the trees in
between are moving in the wind. I don't have any experience with
Waverider, but I sure have had some with 900MHz in the forests with
Metricom. Getting the signal to stay put was a big problem as the
path through the forest was never direct. 900MHz would go though the
branches but not the trunks. Put enough trunks in the way and nothing
would work. Tree trunks swaying in the wind would open vertical
"slots", which would dramatically improve propagation for a few
seconds, and then die as the trunk swayed the other way. The only
solution was to get as much gain as possible at the client side
antenna and hope for the best. Moving the antenna around was also
useful, but was by no means a guaranteed solution.
>I do have a lot of trees by me but I have put together a tower that
>should be putting me above the tree line.
How many trees in a "lot"? How many miles of trees are you trying to
penetrate? What type of tree? Thick forest or thin? Ignoring the
trees, do you have line of sight or is there a hill, mountain,
building, or something in the way?
>I was under the impression that it had to be something on the ISP side
>but they claim not to be causing any problems and I am just not
>sure...so I thought that I might ask around about things that could be
>causing my problems.
Good plan. I like to do the numbers first, before doing the field
trip. Calculate the line of sight and the fade margin first.
Take your EUM and go for a drive. Get a 117VAC inverter for your
vehicle, a laptop, perhaps a spare antenna, and take it to some place
with a clear line of sight to the CCU at approximately your
unspecified range. Duz it work? Is it stable? If not, there's
something broken in your EUM. It's probably not the CCU or there
would be a rioting mob of irate customers at the ISP's door.
If that works, put some trees in the way, but no mountains or hills.
Just trees. Duz it still work? Monitor your signal strength. Is it
stable? Keep going until it craps out. Is it about the same as your
location or farther?
--
Jeff Liebermann
jeffl@comix.santa-cruz.ca.us
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558
900 MHz waverider & ISP problems 
Linear Mode
