On 3/5/2012 8:26 AM, Jeff Liebermann wrote:
On Mon, 5 Mar 2012 15:09:40 +0000 (UTC), alpha male
wrote:

On Sat, 03 Mar 2012 19:43:47 -0800, Jeff Liebermann wrote:
What is the OP trying to accomplish?

The neighbors and are discussing setting up a neighborhood mesh network
and we need to ascertain, beforehand, where to place masts and which
direction to point them in our mountainous neighborhood (Skyline& Summit
area).

Ok. Go thee unto:
http://www.cplus.org/rmw/english1.html
Follow the destructions at:
http://www.cplus.org/rmw/download/download.php?S=1
For maps, download the SRTM3 maps for your area from:
http://rmw.recordist.com
Do not bother with DEM, SRTM1, or other maps. Do NOT unzip the maps.
My directory shows about 600MBytes of SRTM3 data for everything for
the SF Bay and Monterey Bay areas. You can set Radio-Mobile to
automatically download a map if needed, but it's easier to just
download the maps ahead of time.

Follow a simple example such as:
http://www.cplus.org/rmw/afirst.html
to get started. There are also numerous tutorials on the web.
Note that the program uses the concept of "networks" which will be key
to modeling a mesh. Locate your nodes, use realistic values, and
build a model. This part is a PITA and requires considerable time and
effort. Draw the (optical) coverage areas for each node, and the line
of sight:
http://joelgranados.wordpress.com/2011/11/05/wireless-link-calculations-radio-mobile/

You're going to have a big problem in the Santa Cruz Mountains call
trees. These are cellulose and water obstructions that may or may not
appear at the correct altitude on the elevation profiles. 2.4GHz will
NOT penetrate foliage, especially when wet. You'll need to manually
adjust your path profiles for the tree line. If the trees are inside
the Fresnel zone, you'll have losses.

If you have problems, ask here, or preferably the Yahoo Radio-Mobile
group at:
http://groups.yahoo.com/group/Radio_Mobile_Deluxe/

I have a really bad attitude about mesh networks. Bug me if you want
to hear the full rant. For a sample, see the dismal performance of an
early mesh network (MIT Roofnet - Meraki).
http://pdos.csail.mit.edu/roofnet/doku.php?id=interesting
"Surprisingly, the performance over a two hop route is
less than 1/2 that of one hop routes, implying routes
tend to interfere with themselves."
Also:
http://sha.ddih.org/2011/11/26/why-wireless-mesh-networks-wont-save-us-from-censorship/
covers the main problems. Do you really want a phone call at 2AM from
a neighbor asking if the network is down?


I've used Radio Mobile and SPLAT!. I never got a warm and fuzzy with
Radio Mobile. Of course, it is a bit more complicated to use SPLAT!.

One obvious advantage to SPLAT! is it can analyze very large areas. Not
all that useful in the case of this wifi setup, but very useful in sigint.