Since I wrote the paper on Wireless
Topology, I have received many request to build out mesh networks;
but my objective is to build my own network first. As a result I started
to build a small wireless mesh in my neighbourhood. Linking friends and
family together. The problem that I have is my hardware configuration
does not match the physical topology of the landscape. Even though I
following my plans out I found that the wrong antenna and the placement
of that antenna can create some major performance problem.
I have a node that is sitting 16 floors up using 8 dbi
down tilt built into the antenna. The problem is that only some of the
signal is getting to the actual antenna that is besides the building
(yellow circle.)
What to do? I recently acquired a 200 mW radio card that has antenna
diversity. I place a directional antenna pointing upwards to the node
that is on the 16th floor; I've place a second regular 8 dbi antenna
above the directional antenna i.e. two different antenna on the same
radio card.
I also set Wiana Diversity to have a hi pin TX and low pin RX where the
omni was on the RX. Great. The link strengthens but the connection to
the gateway sucked. When tested the performance of the node on the 16th
floor was similar to that of the node below it. I was able to improve
the nodes performance by placing the antenna and radio card in a new
position.
I replace the 200mW back with the MA311 and left the node on the 16th
floor to have poor performance once again. I took a second solution by
adding another node to further away from the building and with in
tolerance of the down tilt antenna. Guess what. It works much better.
Two solution, two different results.
