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Paul, that is very interesting! I am particularly interested in what
kind of throughput you can get on that frequency. Do you attach an
external antenna to one of the RP-SMA connectors?<br>
<br>
As for battery power, I've been experimenting with providing power
to a Raspberry Pi using a series of D-cell batteries. D-cells have
the most energy capacity per density/size than any other common
consumer battery, from my investigation. For the RPi, which uses 5V
USB power, drawing 500-1000 mA, a couple alkaline D-cells could last
2-3 days. I bet this could work for your Mesh Helper as well. All I
needed to get that working was a simple step-down DC-DC converter,
which costs US$2 max. A handful of D-cells aren't exactly
pocket-sized, but certainly something you could stash in a backpack.
I'm about to buy a high-current solar cell as well, to try to make
an always-on solar-powered device.<br>
<br>
Let us know of your progress!<br>
<br>
Dan<br>
<br>
<div class="moz-cite-prefix">On 02/07/2013 09:46 AM, Ben West wrote:<br>
</div>
<blockquote
cite="mid:CADSh-SOXH6+YSWkdwu5iXXat0Y7onLyFWbTWTnAOohTVvtgtJw@mail.gmail.com"
type="cite">Likewise, Ubiquiti also sells 900MHz versions of their
Nanostation and Bullet access points. I understanding these units
essentially just have 2.4/5.8GHz chipsets that have been
translated to a different band, and with some consequent penalty
in spectral efficiency.<br>
<br>
E.g.<br>
<a moz-do-not-send="true"
href="http://www.wirelessnetworkproducts.com/locom900.aspx">http://www.wirelessnetworkproducts.com/locom900.aspx</a><br>
<br>
I would like to assume OpenWRT and derivatives will run w/o
complaint on such 900MHz units, but I'm guessing it's not that
simple.<br>
<br>
<div class="gmail_quote">On Wed, Feb 6, 2013 at 11:00 PM, Paul
Gardner-Stephen <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:paul@servalproject.org" target="_blank">paul@servalproject.org</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi All,<br>
<br>
Just a heads up on some stuff we are doing at Serval that I
think will<br>
be of interest to Commotion deployments more generally.<br>
<br>
We are now actively working on what we call our "Mesh Helper
Device",<br>
the prototype of which will consist of a TP-LINK WR703N
running<br>
Commotion OpenWRT + servald, connected to an RFD900 ISM 915MHz
band<br>
packet radio and a rechargeable battery.<br>
<br>
This gives the potential for much greater range than just
WiFi, as<br>
well as offering some resistance for 2.4GHz jamming in places
where<br>
that is a problem.<br>
<br>
The RFD900s with current firmware in urban settings offer 5x
to 10x<br>
range compared with WiFi. For example, I could receive a
decent<br>
signal with one radio sitting on my lounge, and the other
radio with<br>
me walking around the block, up to about 150m away -- with the
signal<br>
path obliquely through perhaps 8 or 10 houses, fences, cats,
dogs,<br>
trees and everything else.<br>
<br>
With good clear line of sight, and a low noise floor, ranges
of 10km<br>
or more are possible, with some evidence pointing to the
actual limit<br>
being around 80km - 120km in very ideal conditions.<br>
<br>
We have already managed to get Serval Mesh traffic, including
some<br>
Rhizome transfers (but not yet voice) running over one of
these links:<br>
<br>
<a moz-do-not-send="true"
href="http://servalpaul.blogspot.com.au/2013/02/breaking-wifi-barrier-serval-mesh.html"
target="_blank">servalpaul.blogspot.com.au/2013/02/breaking-wifi-barrier-serval-mesh.html</a><br>
<br>
We think a complete Mesh Helper Device, including these really
nice<br>
radios could be built and sell for <US$200. It may also be
possible<br>
to use a cheaper compatible (but slightly lower performance)
radio and<br>
get the price down to <US$100.<br>
<br>
The RFD900 firmware only does point-to-point communications,
but it is<br>
entirely possible to make it do "ad-hoc" point-to-multipoint<br>
communications. Perhaps this is something for us to look at
as a<br>
follow on after our current work block is complete.<br>
<br>
We are hoping to have a couple of these with us in New Zealand
in a<br>
couple of weeks for the KiwiEx field trial. General outline of
our<br>
thinking for KiwiEx at present is at:<br>
<br>
<a moz-do-not-send="true"
href="http://developer.servalproject.org/dokuwiki/doku.php?id=content:exercises:kiwiex2013"
target="_blank">http://developer.servalproject.org/dokuwiki/doku.php?id=content:exercises:kiwiex2013</a><br>
<br>
If there are other things people would like tested while we
are there,<br>
let me know, and we will endeavour to cover them.<br>
<br>
Paul.<br>
<br>
_______________________________________________<br>
Commotion-dev mailing list<br>
<a moz-do-not-send="true"
href="mailto:Commotion-dev@lists.chambana.net">Commotion-dev@lists.chambana.net</a><br>
<a moz-do-not-send="true"
href="https://lists.chambana.net/mailman/listinfo/commotion-dev"
target="_blank">https://lists.chambana.net/mailman/listinfo/commotion-dev</a><br>
<br>
</blockquote>
</div>
<br>
<br clear="all">
<br>
-- <br>
Ben West
<div><a moz-do-not-send="true" href="http://gowasabi.net"
target="_blank">http://gowasabi.net</a><br>
<a moz-do-not-send="true" href="mailto:ben@gowasabi.net"
target="_blank">ben@gowasabi.net</a><br>
314-246-9434<br>
</div>
<br>
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<br>
<pre wrap="">_______________________________________________
Commotion-dev mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Commotion-dev@lists.chambana.net">Commotion-dev@lists.chambana.net</a>
<a class="moz-txt-link-freetext" href="https://lists.chambana.net/mailman/listinfo/commotion-dev">https://lists.chambana.net/mailman/listinfo/commotion-dev</a>
</pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Dan Staples
Open Technology Institute
<a class="moz-txt-link-freetext" href="https://commotionwireless.net">https://commotionwireless.net</a></pre>
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