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Advise for starting a node in my city?

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Advise for starting a node in my city?

I have no nodes within 100 miles according to the ARDEN map. Based off placing a node at 25 feet (on my roof) I can cover quite a bit of of ground (majority of my city minus a few higher elevation areas.) So even though there are no nodes listing I figure it has to start somewhere so I have a few questions to get this going:

1) How accurate is the website in terms of coverage? I know nothing is 100% accurate and many variables come into place but is the site a good reference point? 

2) Antenna recommendation? I know a 360 omni antenna is not as ideal as a directional but with no nodes in my area to coordinate with I am thinking to start off 360 might be the way to go until more nodes show up. is this a poor approach to start off?

3) Since my area is a clean slate I am thinking 5.8 ghz mimo node. Any recommendations on a node/antenna combo for maximizing performance in my situation?


KE2N's picture

The tool in #1 is pretty nifty.  But it seems to only support the AC devices which are not supported by AREDN. So any data rate predictions will be a lot higher than what you will actually get.  As usual for these types of LOS tools, the effects of trees, man-made structures, etc., is not included. It seems like the signal is 100% until the Fresnel zone touches dirt and then the signal suddenly drops to zero. That is a highly simplified approach. 

Bear in mind that one large leafy tree will totally block a 5.8 GHz signal.  So, if you are planning to have your antenna at your house, go out in your yard and look at the tree tops in the direction you want to go.  That is your minimum required antenna height.

I knew trees could be an

I knew trees could be an issue but really 1 tree kills the signal? Would going with 2.4 ghz be a better choice or is it not much of a difference?

KE2N's picture

At 2.4 GHz it takes two bushy trees to kill the signal.

You can, of course, kind-of skim tree tops and get a gradual reduction in signal strength and/or link quality.  And you can go between (and even under) trees and get away with it.  But going right through a stand of trees will kill the signal, or make it unreadable due to scattering effects.   

Out west they can stick antennas on a 3 foot tall tripod and have a 60 mile LOS view.  

East of the Mississippi, most of country is basically a forest. Most of the permanent setups I have seen involve antennas on tall buildings, towers (towers on mountains) and on water tanks.   

If you can clear the tree tops you can get good paths.  Attached photo - testing a 5.9 GHz link using a Rocket M5 and 30 dB dish on a Hospital roof to another Rocket M5 using sector antenna mounted on a 90 foot tower located in those low mountains in the distance (1100 ft asl).   Signals were about -75 dBm as I recall, over a path of 20 miles. 


Image Attachments: 

I appreciate all the information everyone! I am just going to have to climb back on the roof and see what I can see for line of sight. Richard is correct that I am surrounded by trees. While I cut down mine I cant do anything about neighbors trees. I am currently playing with 4 Hap AC lite units placed around my house but wanted to get a little more out there. I guess in the mean time I can play with these 4 some more and maybe tunnel to another node until I can find an alternative solution.

nc8q's picture
Starting an AREDN network in Erie, PA.

Maybe start here:
and contact the folks on the 'Contacts' page.

Maybe ask the web editor to put this link on their 'Links' page:

Hope this helps.

AA7AU's picture

Four things to remember when discussing "clearing the tree tops" are:
1) the dreaded Fresnel zone (which everyone tends to "finally" remember);
2) a deciduous tree's leaf "presence" changes with the seasons (or drought etc);
3) those damn trees keep growing, so maybe OK this year and perhaps not the following; and,
4) those tree tops can move in all different ways due to the [occasional] winds.
This is just as true "out west" as it is in the forests of the central and eastern parts of the US.
Been there, done that. Two's company, tree's a crowd!

Also, microwave tends to fade/drift/etc due to other atmospheric conditions, including thermal inversions etc etc. If you're marginal today with your tree situation, tomorrow might not be so good and it may not be not the trees. Trees just confuse the situation, always best to be well above then, as pointed out already in this thread.

One other thing: some folks don't enter their lat/lon for various reasons including HOAs etc, and/or don't connect thru the interwebs to update maps. Be careful about false negatives when using maps to determine neighbors. Local word of mouth or a good site study is the best way to find who's out there. Pick a band, and then run scans from your node using 5, 10, and 20MHz to list who the node can see in the band with each of those bandwidths. You can get surprising results.

Good luck,
- Don - AA7AU

AREDN - Coming to a city near you!  (tm)

AA7AU's picture
Another thought or two

If you're starting your area for AREDN, your choices early on may dictate the way the mesh topography grows there in future. Opinion: there is only one really usable channel in 2GHz (-2/10) so best to not start out there unless there are already others around you using it that you want to connect to.

We have an issue in the LV metro area where one user (who only lives there part-time) put a -2/10 node on a high [dominant] mountain early on, and now is claiming that only MIMO modes can connect to it. Results in conflict with other local 2GHz node users who might be using older pre-existing non-MIMO gear. OTOH, here in our mesh island up in Idaho we very successfully share that same -2/10 channel between MIMO and non-MIMO nodes, both in the valley and in much higher locations - but it's a rurral area and we got on-line first here. Kind of like being the first to design a local "band plan".

Probably best to get 5.8GHz gear to start. Lots of part97 channels to pick from, not as much noise floor in general, and some really neat options keep appearing due to the hard work of the AREDN team - such as the ability to re-purpose old sat dishes with inexpensive plug-ins and great directional links.

But remember the journey to a good local network begins with that first single step. Make yours count.

Just some thoughts,
- Don - AA7AU

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