On Sat, 4 Aug 2012 02:46:35 +0000 (UTC), "Vinny P."
wrote:

Here's how my friend Simon explained it to me today ... so I hope to have
more data this weekend.

It's a bit more complexicated than that. Just because you can see the
other end, doesn't mean that a 2.4GHz link will be reliable. Any
objects inside the Fresnel zone will cause problems. Reflections off
the ground will cause nulls and peaks. Moving objects (cars) close to
the path can cause fades. I use Radio-Mobile softwa
http://www.cplus.org/rmw/english1.html
to produce path profiles like this:
http://802.11junk.com/jeffl/coverage/K6BJ-to-KI6EH/K6BJ-to-KI6EH-Path-Profile-01.jpg
This one is at 420MHz and has some errors in the numbers, but gives a
tolerable idea of what can be done. All you need to do is supply some
numbers.

A simpler version is just the path loss.
http://wireless.navas.us/index.php?title=Wi-Fi#Link_Calculations
that simply calculates the fade margin, which directly translates to
reliability and uptime. I'm fairly sure you're close enough that
there are no path loss issues. I'm not so sure about obstructions
along the path.

If you look at the antenna profile for the NanoBridge M2,
it shows you how much loss to expect if you are a few degrees off target.
If you are 15 degrees off-target, you lose about 7 dB.

6dB loss is the same as cutting your range in half at the same signal
levels.

Another way to think about it is how much of your dish antenna can you
cover in order to produce a -6dB loss? Well, covering half will be
-3dB loss. Another half will be -6dB. So, how well does your dish
work with a dish only 1/4th the size?

In other words, aiming is not your problem.

Probably true. Something else is wrong which might be indicative of
defective equipment. The easy way to determine that is to compare
with a similar piece of hardware.

Did you ever settle on vertical or horizontal polarization?

We see random fluctuations in signal strength that dwarf anything like a
5 degree aiming error.

Random fluctuations as in fades and nulls is exactly what you get when
there are multiple reflections and objects in the Fresnel zone.

I have the tripod, and a bunch of brand-new NanoBridges. You can ride
along with me and we can set it up at different places along the road and
see what kind of signal and speeds we get, with and without the power
lines and towers in the way.

Great idea. Do it.

I'll be bringing it to Joe's house and Bill's house today or tomorrow,
and you can help set them up if you like, and we can get measurements
from those places as well.

Even better. Remove your Nanobridge and bring it along. Compare
signal levels.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558