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Just thought I would jot down a few notes about some experimenting I've been doing with the mesh. Here is the scenario: Mesh node atop 40' tower, surrounded by trees, power lines, and all kinds of other clutter. The "path" is also cluttered with trees that are over 75 feet tall. Trying to establish a connection with another node approximately 35-40 feet up at half a mile away.
The challenges are punching through (or bouncing around) the two-story houses in the area. First tried using Omni's. Forget about it, not enough gain to get any distance at all. Tried using a parabolic and it was almost as bad as the Omni's. Since I am no expert on the matter the only thing I can deduce here is that the beam on the parabolic is too narrow and has no chance of getting "around" things. Then tried a pair of 14Dbi, 23 Degree sector antennas. Results showed some promise as I was able to pick up a signal most of the way to the second node (I was in a van with dual mag-mount omni's on top). Still no signal at the second node location though. Decided to try an experiment using an amplifier, but didn't feel like climbing all the way up the tower to install the new equipment. instead I decided to set up a quick node at about 25-30 feet (this way I could simply stand on the roof-top). Set up a couple of the sector antennas with one having an 8 watt amp on it. Was able to get an intermittent signal at the second location. Since the parabolics seemed to be too narrow and the sector antennas didn't seem to have enough gain, I've ordered a couple of Yagi style antennas that have about the same horizontal beamwidth but with a bit more gain. Some things to note, even without the amplifier from the 40 foot tower to a vehicle with a couple of mag-mount omnis I was able to get anywhere from .25 to .33 of a mile through the clutter. The amplifier only gained me a couple hundred feet of distance but feel it helped the "bounce" effect. I know it is said that if you can't get line of sight, you can't get a signal. Technically this is true. But you also have the bounce effect which can never be planned nor counted on. The moral of the story is. If at first you don't succeed, try something else. If that doesn't work, try another option. You'll be surprised how much you'll learn about mesh networking and 2.4Ghz propagation during your experiments. I have two other Hams that are located between the two locations and could have contacted them and tried to get them to set up a node. But that would have been too easy and I may end up having to go that route, but I would much rather have the two nodes functioning, then go to them and say, "See how well this can work". With any luck we can get more Hams in the area interested in the technology and have them bring up some nodes themselves, then it will be a matter of getting these "clusters" all connected. Have some more experimentation coming where their will be access to some taller buildings. Unfortunately we will still need to contend with the surface clutter (buildings & trees) to get the average Ham tower (30-40 feet) the proper set up to punch through and bounce around the clutter. Just thought I would share some of the experimentation with everyone and hopefully give some people some ideas for their particular situations.
73's Jess KC9QEA
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