[Battlemesh] recommendations for 40Km Link

Nicolás Echániz nicoechaniz at altermundi.net
Mon Mar 24 22:58:40 CET 2014

El 24/03/14 00:12, Dave Taht escribió:
> On Mar 22, 2014 9:25 PM, "Nicolás Echániz" <nicoechaniz at altermundi.net
> <mailto:nicoechaniz at altermundi.net>> wrote:
>> El 04/07/13 05:00, Joseph Bonicioli escribió:
>> > Links of that distance are very common in our network (AWMN). Attika in
>> > Greece is not flat resulting to many links that are over 10 20 or
> even 50Km.
>> > Moreover since we got access to TV channel installations we have a
> lot of
>> > long distance links to other areas of Greece and with other wireless
>> > communities . It will be pointless to point some out. They are many
> and I
>> > own a couple of them.
>> >
>> > Do not over analyze. Maths never fail you (FSL calculations)  and rocket
>> > dishes are fine for 40Km. With 34dbi dishes at both ends you will
> get -71db
>> > signal with no Tx power at all. If you add 5-10db Tx power you will
> be well
>> > in the good performance zone of -61 to -66.
>> > If you are in a noiseless environment you will be thrilled to find
> that the
>> > performance will be "just" as good as in your test room.
>> > You can also find cheaper alternatives. Get yourself a couple of
> good solid
>> > reliable 120cm offset dishes, a couple of feeders that we can
> provide you if
>> > you need to and you are ready.
>> >
>> > On the other hand don't consider anything less than the biggest gain
>> > (biggest dishes) and most reliable hardware you can get. You will
> have to
>> > compensate for bad weather in the winter making the link harder due to
>> > conditions, harsh environment may punish hard you equipment and of
> course
>> > unreliable hardware/software will make you travel a lot. The difference
>> > between some extra cash for something a bit more reliable and traveling
>> > expenses is big.
>> >
>> > And don't worry about details like alignment. Those things nowadays
> if you
>> > have not broken something in your equipment are a breeze with the
> tools that
>> > you get.
>> > Plan for other details if you are going somewhere far or on a mountain.
>> > Cables, extra tools, insulation material, things that make your life
> and the
>> > experience pleasurable, communication equipment, ropes, toolboxes,
> people :)
>> >
>> > Go play, take some pictures and let us know the results! Good luck!!!!
>> We finally got around to finishing our first long distance (50Km) link
>> and it's working great.
>> Thanks joseph for the hints and optimism :)
>> We published a small blog post (in spanish and english):
>> http://blog.altermundi.net/article/completamos-el-enlace-de-50km/
>> with some details on link conditions, quality and photos.
> I am impressed. Was the link really 50 Mbit in both directions
> simultaneously? Are you using airos or OpenWrt?

We plan to use OpenWrt everywhere when ath9k gets more stable, so far we
have had different issues with every release we tested for the past year
or so.

So here's what AirOS "speed test" is reporting:

running it repeatedly gives similar results every time.

Check the blog post for other images, like terrain profile, etc.


> Got Bufferbloat? What does a rrul test look like? (See netperf-wrappers)

We'll have to wait till we can upgrade to OpenWrt

> How well does it work in rain?

It hasn't rained since we set this up. I will report when it does.


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