NEW: Quick getting started guide for setting up an outdoor mesh node

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Step by step guide to getting onto Pretoria network


The first edition of "Wireless Networking in the Deveolping World" is available as e-book now. Prints can be
ordered on demand at The e-book is available at no cost under a creative commons license.
Get your copy at wndw or locally and share it.

Step 1. Check where you are on the planet:

Your very first step is to find your current position on a map and then see what other wireless nodes are nearby. The best way to do this is to get a GPS and find out your coordinates and then to enter these into google earth - you can also use google earth to find your coordinates by identifying your house on the satellite image.

Step 2. Check who else is around that you can connect to

Once you have entered your google earth position - have a look at the positions of other wifi installations around you. For the Pretoria Mesh we have stored all the google earth positions in this file. You can also have a look on sites like NodeDB to see if there are other wireless installations near you. Once you have identified someone that you want to connect to, the best way to check connectivity is to use a WiFi sniffer such as netsumbler for windows or Kismet on linux loaded on a laptop with a Wifi card fitted with an external antenna. Find the highest point at your house such as your roof and slowly rotate the directional antenna around you to see if you can pick up any WiFi access points. You will want to find an access point that is in ad-hoc mode and is mesh enabled - the wifi sniffer will tell you if the wireless node is in ad-hoc mode but you will have to contact the owner to check what mesh protocol, if any, they are running.

For the Pretoria network you will be looking for any node with the SSID: ptamesh

Step 3. Build a mesh node

Now that you know where you are located and you have hopefully found someone you can connect to, you will need to construct your mesh hardware. Have a look at the diagram at the top of the wiki for a description of all the components that make up an installation. Below is a shopping list of all the components together with the suppliers that provide them and prices.

Shopping list

× Item description Supplier Supplier Stock Code Quantity type Cost Quantity Total
1 1.5m 38mm Aluminium mast MIRO AP-38x150 EACH R48.00 1 R48.00
2 Wall Bracket - Large - 250mm (tripod) MIRO WB-250-15 EACH R54.45 1 R54.45
3 Coach screw with wall plug MIRO COACH EACH R2.42 3 R7.26
4 50mm U Bolt (Mast to Wall Bracket) MIRO UB-50 EACH R4.24 2 R8.48
5 LMR400 Cable (per Meter) - Loss 0.2dB /m MIRO LMR400 METERS R24.20 3 R72.60
6 N-Type (Male) Connector for LMR400 Cable MIRO N(m)-400 EACH R66.55 2 R133.10
7 Weather Proof Box ROSS RL2P EACH R129.60 1 R129.60
8 12dBi Yagi Antenna - 2.4GHz MIRO PA-12-YAGE EACH R290.40 1 R290.40
9 CAT5 single core cable /m Compucable xxx METERS R1.75 20 R35.00
10 Ethernet connector and jacket Compucable xxx EACH R1.48 2 R2.96
11 Pigtail RP TNC - N FEM Bulkhead WEBB xxx EACH R160.00 1 R160.00
12 No 0 13mm Gland ROSS xxx EACH R15.00 1 R15.00
13 Linksys WRT54GL MIRO LS-WRT54GL EACH R647.35 1 R647.35
14 3.5mm Power Jack ROSS xxx EACH R2.50 1 R2.50
15 Power over Ethernet Injector (CAT5) - Base - no PSU MIRO 12V-POE EACH R108.90 1 R108.90
TOTAL R1715.60
VAT R240.18

Tools and accessories needed

× Item description Purpose
1 GPS Establish coordinates of site
2 Signal measurement device Measure signal strength to establish Antenna gain required
3 >650W Drill For Drilling holes to mount wall bracket
4 11mm Masonary drill bit For Drilling holes to mount wall bracket
5 Duck tape To secure box on mast
6 Ethernet crimping tool To build custom ethernet cable length from box to PC in house
7 Size 10 Spanner For Antenna bracket nuts and U bolt nuts
8 Size 13 Spanner For Coach screws
9 Flat Screwdriver To open waterproof enclosure
10 HT Tape To seal RF connectors at Box and antenna
11 Ladder Best to use this instead of pole vaulting onto roof
12 13mm Hole sore To drill 13mm hole for N-Type Bulk head and gland for ethernet

A mesh network node consists of a wireless router, antenna, routing software and settings.

Wireless Router

Your wireless router can either be a PC with a wireless card, a dedicated Wireless Router unit or SBC Single Board Computer with a wireless card. A dedicated Wireless Router is the most popular choice because it is relatively cheap, easy to configure and low power making it practicle for a device that is meant to be on most of the time. Have a look at Cost Tables to get an idea of all the possible types of mesh nodes you can build together with the cost implications


The first step is to select an antenna that suits your situation best. There are several types of Antennae:

1) Omnidirectional
2) Yagi-Uda
3) Grid
4) Flat-panel
5) Wave-guide

The main difference between these antennae is the Radiation Pattern. Each type is also available with different Gain specifications. Typical Wireless Routers are sold with 2 omnidirectional antennae and these can be re-used as part of your node, depending on your situation. If you have other nodes in your vicinity that are spread out in all directions but are fairly close (i.e. < 3Km), then an omni-directional antenna should suffice. If the other nodes are concentrated in one direction, for example, if you have a hill on one side of your house and theres no point in radiating the hill, then you may want to choose a more directional antenna, like a 180 degree Flat-panel. For point-to-point links, a smaller radiation angle is needed and Grid or Yagi-Uda type antennae are probably best suited.

Step 4. Install latest mesh networking firmware

The type of software that needs to be installed will typically be implmentations of mesh routing protocols like OLSR, as well as security software, like VPN clients. On dedicated wireless routers, this is typically implemented on Firmware, while on standard PC's its implemented in Software.

WRT54G Firmware update

Wireless Routers like the WRT54G are not mesh capable as is. One of the reasons for selecting the Linksys is that the Firmware is upgradeable.

Caution: Please note, that fiddling with the firmware will void your warranty!!!

The following instructions apply to networks running the OLSR routing protocl, like the Pretoria Mesh.

1. Download freifunk firmware from Freifunk site or Local

2. Set boot wait on linksys

Web method:

Navigate to web page were you can send pings and type each of these lines one line at a time


NVRAM method:

telnet into box and type the following

nvram set boot_wait=on nvram commit reboot

3. Upload firmware

Give yourself a fixed IP in the 192.168.1.x range e.g.

Use tftp to upload firmware

tftp> binary
tftp> rexmt 1
tftp> trace
Packet tracing on.
tftp> put openwrt-g-freifunk-1.0.2-en.bin

Wait for the power light to stop flashing Power cycle the box

Step 5. Install mesh node

HowTo Water-proof your equipment

Step 6. Setup mesh configuration

1. Check that the web interface is working. Visit the site on your web browser - you should see the main freifunk web interface appear

2. Set up the wireless interface

WLAN protocol: Static
Ip Address:
WLAN Mode: Ad Hoc (Peer to Peer)
ESSID: mesh
Channel: 6
TX Power: 100

3. Set up the LAN interface

LAN protocol: Static
LAN Netmask:
Disable NAT: yes
Disable Firewall: yes

4. Set up the WAN interface

WAN Protocol: DHCP
Host name: Lawrence

5. Set up OLSR


6. Restart the Linksys

You should now be given an IP address in the 192.168.3.x range You should be able to connect to another mesh access point and even get a default gateway to an internet point, if one exists

Step 7. Start surfing

Hopefully you`re now hooked up to the internet and you can start surfing the web or hooking up to other PCś on the mesh

Step 8. Troubleshoot

Start with Layer 1:

Is everything switched on?
Is the LAN plugged in?
Is the Antenna connected?
Is it facing the right direction?
Is it polarised correctly?

Check software settings:

Is the correct antenna selected?
Is the routing daemon running?