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[liberationtech] Crowd-Funding Serval Mesh Extender

Yosem Companys companys at
Wed Jul 10 11:55:28 PDT 2013

From: Paul Gardner-Stephen <paul at>

As some of you may already be aware we have been working on what we call 
the Mesh Extender at the Serval Project.

The Mesh Extender is a combined battery powered embedded Linux router and 
UHF packet radio running the Serval Mesh software (which is all GPL, see for the source). 

It is intended for mobile and truly ad-hoc deployment where the end user 
just turns it on and uses it.

The idea is that it uses the UHF packet radio to mesh over greater 
distances than is possible with Wi-Fi, the trade-off being lower bandwidth.

In general, we find that the UHF packet radio has a range of about 10x that 
of Wi-Fi when deployed indoors with omni-directional antennae.  This means 
it has a range of about a block in a suburban or urban setting compared 
with Wi-Fi's range of about one house or apartment.

For example testing it in Boston recently we had coverage over much of the 
MIT campus from a single Mesh Extender in my room at a nearby hotel:

Extending the range in this way is a critical enabler for the adoption of 
mesh communications because it removes the need for skilled installation 
and lowers the required penetration rate from near 100% in a local area if 
using un-aimed Wi-Fi to below 1%:

Combined with the always-on end-to-end encryption of voice calls and text 
messages of the Serval Mesh we think that this device has the potential to 
play a significant role in enabling distributed, resilient and private 
communications for people in a wide variety of situations.  

We also see that the close alignment of what the Freedom Box and Serval 
Project are trying to achieve means that any device like this that we 
create could easily be adapted to being both a Mesh Extender and Freedom 
Box by adapting the included software inventory.

The necessity of a portable and trivial to deploy enabler of mesh 
communications, and the need for this to be completely open, has led us to 
the current point where we have setup a crowd funding campaign to develop 
this technology, taking it from the prototype stage and to develop an 
actual manufacturable product, and do further testing with our humanitarian 

This is the point that our campaign at will take us 
to if fully funded.

But to realise the full potential of this we not only need to make an 
attractive manufacturable device, but also to improve the open-source 
firmware of the packet radios we are using to support true "ad-hoc packet 
radio" within the complex regulatory requirements of the ISM 915MHz band, 
in particular the need to frequency hop which presents interesting 
technical challenges for a fully distributed mesh that does not rely on GPS 
timing for synchronisation.

Achieving "ad-hoc packet radio" will require us to not only meet our 
current funding goal, but stretch it by a factor of two.

We are conscious that achieving this will require promoting the campaign 
far and wide, possibly wider than the Serval team can achieve alone.

Therefore it would be tremendously helpful if as many of you as are willing 
and able would assist us in spreading the word as far and wide as possible. 
 We would love to get slash-dotted and reddited off the net. Repeatedly. 

So please take a look at our campaign, use the words below if they are 
helpful, and help us to get the word out, and ultimately let's make 
effective and private long-range mesh communications not only possible, but 
practical and easy for the general public so that they can enjoy the 
resilient backup communications capability that they need to keep 
connected, no matter what disaster may befall them.

Thanks in advance,

Dr. Paul Gardner-Stephen
Founder, Serval Project.


Serval crowd-funding Mesh Extenders to make mesh & disaster telephony go 
the next mile

Serval Project has been working for three years with New Zealand Red Cross 
on free and open technology, called the Serval Mesh, which can keep mobile 
phones operating when mobile networks fail, such as during disasters. We 
now want to take this technology out of the lab and get it into peoples 
hands. Find out more at

Twitter: @ServalProject
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