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11th November – Without Wires


If you operate within the wireless arena (products/services/consultancy etc.), or are a business crying out for BB Access (and in the short to medium term wireless may be the only solution), then this is for you.

All day conference, commencing with coffee and registration at 9.15am and finishing at 16.30pm for networking. Presentations will include:

  • Background Presentation on Baseline Perceptions, What is Wireless, UK Wireless Regime – Nigel King, Orthogon
  • Opportunities for Wireless – Stephen Lowe, Telewest
  • Wireless in Urban areas, Contrast in Rural areas – Tim Cull, Motorola – East Midlands Hub, Case Study – Tim Watton, RABBIT
  • ICT in the Future, Roles of the RDA

After lunch there will be 2 workshops for users and enablers.

The keynote on Rural Broadband will be given by Nigel Heriz Smith of the DTI and there will be ‘Q & A’ sessions following each presentation.

Email for further information.

Bristol Wireless Network Report

Bristol Wireless Network Report

Bristol Wireless currently has 2 main operating nodes running a distribution of Debian Linux. The nodes are situated at the Easton Community Centre (ECC) and the Chelsea Inn (Chelsea). The node at the Chelsea talks back to the main node at the ECC and also runs as an open access point allowing clients to connect in and extend the network range.

Background info:
802.11b standard is 11mbit with roughly 6mbit maximum data transfer throughput.
802.11g standard is 54mbit with roughly 20mbit maximum data transfer throughput.
Most/all 802.11g access points are backwards compatible with 802.11b clients.

There are ready-made access points available which do wireless repeating via wds, but as far as I know do not allow more then one wds connection per unit.

Current nodes are based on DEC multias which are p100 based systems with 32mb ram. They have on board video, network and PCMCIA controllers. We are using Netgear MA311ge PCI wireless cards in these which are based on the prism2.5 chipset by Intersil and have a lot of features enabled in Linux. We are using UMR67 antenna cable runs with a selection of antennas from home made sectors (directional antenna) to purchased omni’s (omni directional antenna)

Clients connected to the network can use any 802.11b wifi compliant device to connect although we have mainly been using the buffalo wifi cards. This is due to their good Linux support and external antenna connectors. The antennas we have used for clients vary depending on their location to a node. We have used home-made waveguides (high gain directional antenna) to quarter wave omni’s (omni directional antenna).

Node Software:
As I mentioned earlier the nodes run a distribution of Debian Linux with daemons such
as zebra (routing daemon) and dhcpd (IP leasing daemon). We use the hostap wireless drivers for the prism based chipset as this enables a lot of extra features such as running in access point mode and wds mode. The Nodes basically run in ap mode and wds mode at the same time allowing clients to connect in as well as backbone links between different ap’s. We use zebra to automatically create and update the routing tables between the different types of links (ap + wds), this allows every machine on the network to be reachable by any other machine without any network address translation (NAT).

Advantages of this network structure:
The main advantage of this network structure is that we can string nodes together and increase the range of the network. As long as you can see a node which can see another node and so on you can be part of the network.

Disadvantages of this network structure:
The repeating nature of this network structure is sound in theory but leaves a lot to be desired in practice. The nature of the 802.11b wifi standard puts a crimp on the whole thing due to being half duplex, their for losing a lot of bandwidth per wireless hop. Due to the nature of RF communications full duplex systems would need 2 radio transmitter circuits running on different frequency’s to allow full duplex operation which works out very costly.

The other obvious disadvantage is that if a node goes down any other nodes beyond that node will lose connectivity and create two separate wifi coverage areas instead of one larger one.

Advantages of our node setup:
The dec mutlias are slimline desktop pc’s and don’t use that much power keeping the running costs down. They also have dual pcmcia slots and a pci slot making them very expandable. They can run a standard distribution of linux making them very customisable. They can easily be wall mounted and don’t create much noise.

Disadvantages of our node setup:
Although the multias are slimline desktop machines they still require mains input and are too large to be mounted on a roof. This means that you need a long cable coming from the antenna on the roof down to the back of the multias wireless card.

The current cable we are using is uniradio umr67 which has quite a high signal loss per meter, this limits the range of the network. The solution to this is to use high quality cable such as times microwave lmr400, but both umr67 and lmr400 are expensive to buy (lmr400 being more expensive due to better quality) This cable is also quite large, 11mm in diameter, and hard to run around the house easily.

Proposed New Network Structure:
The idea behind the new structure is to have one well positioned 802.11g (we will use 802.11b for testing) access point mounted in a box just below a high gain omni on a long pole, this will keep the cable loss to a minimum and provide maximum range.

We will lose the ability to wirelessly repeat but as long as the access point is in a good position we should have no problem with connecting and the range will be much larger. There is the idea of creating a repeating node based on the same software we currently use with a soekris board in a box below the antenna but this works out very expensive.

There are also devices called wireless media converters which basically connect wirelessly (as a client) to an access point and bridge to a wired connection. These would be perfect for clients as they can stick it on the roof and just run cat5 and low voltage power to the roof. This will give no cable loss and should increase the range yet again, there is also the option of having an external antenna on it, the cable loss would be very minimal due to the antenna being right next to the device. Currently I am unaware of any 802.11g wireless media converters but that shouldn’t be an issue as they will be released soon.

Meeting Saturday 11th October

The provisional agenda for the next meeting can be found at

It’s on the twiki so feel free to edit any items.

The minutes of the last meeting are at

The date for this last meeting was input wrong and was actually 23/09/03 NOT August as stated in the link.

The last meeting was inquorate as far as Directors are concerned so any decisions made will have to be ratified at this meeting, so let’s have abig turnout. โ—

The football is showing around the corner at The Plough immeadiately after if anyone wants to join me ๐Ÿ˜€

Update on activities since last meeting see minutes

Minutes can be found at

Training & Support

See last post –

Training will start on October 23rd, it might be an idea to incorporate a surgery night with one of the training nights to clear some of the PC boxen out of the office.

If we do this it might be a good idea also to reschedule the “Give away event” to mid January, still only 12 weeks only, and sell it as a “January Sale” where everything is free (but the wireless cards). It looks like everybody is going to be very busy up to Christmas, so we may not have the people power to do it any earlier.

Neigbourhood renewal

The spec for the nodes and equipment for recipients has almost finished being agreed, the LinuxIT people and the residents association are finalising the machines and printers/scanners, they will have Mandrake installed by LinuxIT. We will be looking at locations fairly soon (late October).

Need to appoint a 3 person (at least) steering sub-committee to co-ordinate roll out of nodes.

Next Meeting

The next Bristol Wireless meeting is supposed to be tomorrow night, but there has not been much activity or commitments to come, and we haven’t got round to doing an agenda yet. I suggest possibly changing it to a less usual time, say Saturday (11th) 5 to 7 pm at the Lab then down to Chelsea for a drink afterwards for them that want to. What do people think? Any other suggestions.

Training News

Rich and Sean from Bristol Wireless have arranged with ECC to use their
computer suite to put on computing training for novices using
Open-Source materials. The idea is to get in the recipients of the
recently distributed Suse installed machines and give them an
introductory grounding in using the Operating Sytem.

The course we have agreed is split into 4 parts

1 Introduction to the Operating system (KDE desktop)
2.Introduction to office (Open Office)
3.Intoduction to the editing digital images (Gimp)
4.Introduction to the Internet (Mozilla)

This will run initially twice over 4 weeks on a thursday evening from

Dates are –

23rd October
30th October
6th November
13th November

27th November
4th December
11th December
18th December

We will be looking for tutors and tutor-support volunteers for all of
the above dates. No funding as yet, but both ECC and us are working on

We also want to try to develop some good course materials as teaching
aids. The idea would be to produce them colloboratively using the wiki
and the bbs ( The possibility of using
the materials as a base to expand the courses so that they could be used
for longer courses such as a proper Gimp course or Opensource ECDL would
be good as well.

OSFoundation and Linux IT are working towards similar objectives from
the other end of the training spectrum (i.e professional linux
accreditation) and we hope to be able to do some work together on this.
As an aside there may be scope for people to do some Linux Professional
Instutute ( accreditation exams at a small cost (or we will
try to get some funding for that too)– more details soon.

Anyone wanting to do the preparation necessary for this could take a
look at the following

Bristol Wireless in Windows Shocker!

I thought it had happened, well I had major suspicions anyway, and am sorry to be the bearer of bad tidings, but many of the machines we gave away on the Give Away Day appear to have gone out with Windows still installed, albeit dual boot.

The Suse installation disks if left to their own devices, as many of them were, automatically detected any existing OS and repartitioned the drive to make the machine dual boot, using only enough HDD space to ensure a GUI Linux install.

We’ve had a few reports of it being slow, but apart from Open Office, this OS should not run slow on the systems we gave away. However we’ve heard reports of systems taking 10 minutes to boot and LILO prompts asking for Windows or Linux ๐Ÿ™

When we write to people about the training we’ll also make an offer to people to bring their machines to the lab for optimisation, if they’re having problems. Then we can sneakily wipe the Mviru$ and install the OS properly! ๐Ÿ˜‰

Volunteers to help welcome.

11th October – Taking Control

Saturday October 11th 10.30-5
Flax Drayton, South Petherton, Somerset

Attendance free • Bring and share lunch • Crรจche
Suitable for old hands and raw beginners alike!
Please confirm attendance before October 9th,
especially if you require the creche for your children

For more information contact UpStart on 0845 458 1473
Email or visit
There are some funds available to help with travel costs, and
we may be able to arrange some overnight accommodation.

Sessions include:
Setting up Housing Co-ops • Worker Co-ops • Car pools and Renewable energy
projects • Supporting and publicising LETS • Developing a community economy
• Troubleshooting for co-ops • and more…

Building a FreeBSD access point

I’ve built myself an access point using FreeBSD, and it’s dead easy!

I have:
One old P200 box (96meg ram, ethernet card, 2gig disk)
One d-link dwl-520 prism 2.5 card
A fresh install of FreeBSD on it ( )

Then to change this box into a functional access point takes just 5 commands!

# kldload bridge
# sysctl
# sysctl"wi0 xl0"
# sysctl net.inet.ip.forwarding=1
# ifconfig wi0 ssid my_net channel 11 media DS/11Mbps mediaopt hostap up stationname "FreeBSD AP"

Now obviously you will want to play with it and customise it, but it will work after doing just those commands. I was impressed. For full details see:


VideoLan – multicast video streaming

Well so far we’ve been unsuccessful at getting this working over wireless, but other people have said that it can be made to work so we will keep at it.

The benefits of multicast streaming is that you can stream say a 4mbit bitrate video across the wireless and have in theory unlimited clients watching it.

Related links: email addresses email addresses are now available.. current retreval methods are pop3 imap and webmail.

Server addresses:

please email to request an account ๐Ÿ™‚