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Rene Hasekamp's picture

How can I bring a problem in the Wireless Leiden network to your attention?

You can send an email to our gebruikerslijst (user's list). Your message will be read by our volunteers and be reacted upon. Use the address gebruikers (at) lijst (dot) wirelessleiden (dot) nl. If you also want to read messages by others, and reactions your message, you can "subscribe" to the messages on the list. Go to the link given above and subscribe!
Huub Schuurmans's picture

Can I, where I live, connect with Wireless Leiden?

This is the mostly asked question ;-)

The answer is: first find out if a Wireless Leiden node is available in your area. Look out of your window, if you can see the node (access antenna) or if you live close then there is a good chance. Also the location (height) of your own antenna is important.

At the walk-in consultancy hour or via the users mailinglist you can discuss your situation with volunteers and other users of Wireless Leiden. They often have a good idea whether a connection is or is not possible at your location.

You can only be sure by measuring the signal strength or trying out. Maybe you can find a volunteer who wants to help out at the consultancy hour.

Huub Schuurmans's picture

Can I e-mail via Wireless Leiden?

1) If you use a PC (Windows, Linux, Mac): You can (only) use webmail, i.e. the webmail portal of your provider or obtain a webmail account such as Gmail, Yahoo-mail, webmail (formerly Hotmail).

2) If you use a smartphone or tablet you can use the Gmail app or the app for your accounts with Gmail or (formerly Hotmail) and download the mail to your device, as with any other WiFi internet connection. We have tested this for the Android operating system. We expect that it will also work with the iOS.
Mail from your internet service provider (ISP; such as xs4all, KPN etc.), however, will only work through Wireless Leiden if you use their webmail service.

Huub Schuurmans's picture

Can I use programs like Skype and MSN Messenger when I internet via Wireless Leiden?

Yes, you can get those programs to work by defining the proxy (if you use a proxy; this is no longer necessary since 2012) in your settings. Which proxy works best depends on your location, so try different settings. If you use linux you can define a system proxy by the statement
export http_proxy="".
Huub Schuurmans's picture

Is the old Wireless Leiden website still available?

No, the old website is no longer available.
Huub Schuurmans's picture

Does Wireless Leiden supply the necessary gear?


The user has to obtain, install and maintain his own equipment . The basic WiFi networking gear can be obtained from any computer store. Antennas, cables, connectors are a.o. for sale at

  • Graficall, Bielsenstraat 1-B, 2316 KA Leiden, 071-5221014
  • Micromax, Van Assendelftstraat 8, 2342AS Oegstgeest, tel. nr 071-5190760
Huub Schuurmans's picture

I would like to contribute to Wireless Leiden, how?

Everybody who wants to make a contribution is highly wecome!

We can use many different types of contribution, e.g.

  • donations/sponsoring,
  • providing access to locations and
  • help out with some of the many volunteer activities.

Anybody who wants to help with the development and professionalization of the organisation and the extension and maintenance of the network are very welcome. We think of people with specific skills, knowledge or experience (handy men for node building, network specialists, radio amateurs, fund raisers, volunteer coordinators, project leaders, student coaches, user advisors).

Also if you like to use the network but cannot help in building / developing the network you can make a contribution. You can report for instance technical problems with the use of the Wireless Leiden accesspoint (node).

Furthermore we are interested in professional users (businesses, organizations) die want to use the network for their company or organisations, for instance set up a VPN (virtual private network) or for offering services.

Finally we are for the financing of the network dependent on voluntary contributions. You can help by making a financial contribution to our banking account NL08RABO0138456062, t.n.v. Stg. Wireless Leiden.

Huub Schuurmans's picture

Can I use the internet for free via Wireless Leiden?

Wireless Leiden is not an Internetprovider!

We only facilitate a local, wireless network that interconnects local users. The use of the local network is free without restrictions. If users of Wireless Leiden want to share their internet connection they can do so. Note that not all providers allow this, check your contract!

There are a number of sponsored internet connections available on the network via 'proxies' (gateways) that can be used by anybody. Since 2012 it is also possible to connect to our network without defining a proxy. The capacity is limited and only webbrowsing is possible (so called 'port 80' and 'port 443' traffic; or 'http' and 'https'). For e-mail you need to use webmail (such as gmail, yahoo-mail, webmail, etc.) or use the webmail portal to your e-mail account. For MSN or Skype you have to define the proxy settings in these programs, if you use our proxies.

Huub Schuurmans's picture

Why can I only use a webbrowser when I use Wireless Leiden Internet?

The reason is that we want to prevent undesirable or illegal use of the (sponsored) internet connection.

Anybody can use the local network of Wireless Leiden, provided he/she compies with Dutch law. When you use the Internet you are using a gateway that only passes webbrowser traffic. This is a requirement of the Internetproviders to prevent abuse (such as sending spam).

Huub Schuurmans's picture

I am willing to contribute,but this seems rather complicated stuff, could I really be of help?

Yes, everybody can make a contribution to Wireless Leiden. There are a lot of things that need to be doen and absolutely not only for computer geeks (although they are always very welcome!).

Who is a handy do-it-yourself person can help with building and maintenance of antenna installations (nodes).

Also consider:

  • organisational and adminstrative work,
  • coaching and coordination volunteer activities,
  • maintaining the website, adding content, write documentation,
  • measuring coverage (automatically collecting local data)
  • give presentations, manning of infostands
  • finding sponsors,
  • coaching students,
  • helping users to connect and/or set up their pc,
  • make a roof top available,
  • (partially) share your internet connection (depending on the contract with your provider).

Come and see us at the walk-in consultancy hour or send an e-mail to the users mailing list. Furthermore we depend for the financing of the network on voluntary contributions. You can help building and maintaining the network by making a donation to our banking account NL08RABO0138456062 t.n.v. Stg. Wireless Leiden.

Huub Schuurmans's picture

Is Wireless Leiden only active in Leiden?

No, we started in Leiden, but we now cooperate with volunteers in Kaag & Braassem, Alphen a/d Rijn, Oegstgeest, Zoeterwoude and Leiderdorp. The total network now reaches from Katwijk to Alphen a/d Rijn to Aalsmeer. See the map with accesspoints.

Huub Schuurmans's picture

Where can I find information about Wireless Leiden?

Information is available on the Internet:

And the 'walk in consultancy hour' (usually on Wednesday night, check this website).

Huub Schuurmans's picture

Antennas for WiFi are rather expensive, can I make my own?

Making an antenna is not really difficult. There is a lot of information on self-made antennas available on the Internet. We have a description (in Dutch) available on how to make a simple cantenna (blikantenne).
A very simple solution is to use a usb-wifi-adapter, if needed with a reflector (handsieve). An alternative is a biquad-antenna.

If you run into problems, come and see us at the walk-in consultancy hour or send a message to the users mailinglist.

Huub Schuurmans's picture

Is Wireless Leiden a cheap alternative for a adsl- or cable connection?

Wireless Leiden is not an internet provider. If you just want to use the Internet and you can get and afford your own dedicated internet connection, we recommend to do so. That way the free, wireless Internet via Wireless Leiden remains availalbe for those who can not get a fixed connection, those who need a connection termporarily (e.g. when moving house or in case of a problem with their connection), those who are visiting (tourists, business visitors) and for use 'on the street'.

An own connection will usually also be faster and more reliable and you can use all internet services, not just web browsing and web mail.

Huub Schuurmans's picture

How about the privacy of the network users?

Wireless Leiden does not know who is using the network, only the identification numbers of the computers (the so-called MAC addresses) are known. There is no user registration.

Users should be aware that the information that they send over the network is not secure. In fact the situation is identical to the Internet. If you want to send private data you have to encrypt your data. This is quite feasible technically, a.o. by using freely available, open source software. Also note that users are on the same local network and other users may see the data (passwords for instance) that you send/receive if you do not use encryption.

Wireless Leiden is NOT responsible for the behaviour of the network users, similar to the situation on the telephone network where the operator is not responsible for what users are doing.

Users should have an up-to-date virus scanner and be aware of the dangers of malware and 'phishing' e-mails.

Huub Schuurmans's picture

How much does it cost to participate?

The use of the network is free (gratis), we do not ask a financial contribution. The (one-time) equipment costs (if you use our network at home) depends very much on the way you decide to make the connection.
  • In the simplest situation you can use your wifi-enabled laptop, phone or tablet without any additional equipment, if the built-in antenna is good enough. You can test this simply by trying to connect.
  • However, often you will need an outside antenna or usb-adapter. A usb-adapter with a 5 meter long cable costs approximately E 25.
  • To provide a desktop PC with a WiFi-card with antenna cable and outside antenna will cost roughly E 100 - 200, depending on e.g. the length of the cable, the antenna type and the construction.
  • A prefabricated, ready to use solution with built-in radio and antenna (for instance a Ubiquity Nanostation) costs about E 80.

We try to keep operational costs as low as possible by the use of open source (free) software and inexpensive equipment, to cooperate with businesses and organisations who e.g. provide access to roof tops throughout the city and by working with unpaid volunteers. The costs of the network are therefore mainly the purchase and maintenance of the hardware. We do not receive subsidies. For our financing we are fully dependent on sponsoring and donations.

If you want to support us financially: our bank account is nr. NL08RABO0138456062, Stg. Wireless Leiden at Rabobank.

Huub Schuurmans's picture

I am inside with my laptop with built-in WiFi. Can I connect with Wireless Leiden?

Sorry, in most cases this will not be possible without an outside antenna or usb adapter.

There are exceptions. It all depends on your situation. For instance if you are very close to a node (less than 100 m) with an unobstructed view and behind an uncoated window it maybe possible.

But otherwise use one of the many methods that are available. Unfortunately the user guides that we have on 'how to connect' are available in Dutch only.

Huub Schuurmans's picture

What is the maximum distance of a WiFi connection?

Practice shows that distances of several kilometers are quite feasible.

The maximum distance depends on a lot of variables: the antennas used, the height of the antennas, the area in between, the nature of the surroundings (e.g. presence of metal). In wooded areas the transmittance is effectively reduced. As a rule of thumb you need a free line-of-sight between the two antennas, which means that you should be able to actually see the antenne of the access point that you want to connect to. Note that also the user has to stick to the legal maximum power of 100 mW, power amplifiers are illegal and a nuisance for your neighbourhood!

Wireless Leiden aims at a distance between nodes of about 800 meter. The distance of the average user to an accesspoint will therefore be about 400 meter. The bandwith at that distance will be close to the nominal bandwidth (i.e. 11 Mpbs and effectively 4 - 5 Mbps nett data velocity); provided there is a line-of-sigtht of course and no interference from neighbouring ap's.

Huub Schuurmans's picture

Are the radio waves of the Wireless Leiden network a risk to human health?


The WiFi radio waves have extremely low power (100 milliwatt is the legal maximum, this is far less than that of a mobile phone) and the accesspoints of Wireless Leiden are outdoors. Therefore the signal is hardly detectable inside homes. The technology that we use is identical to the one that people use at home or office for a local wireless network, e.g. to connect to the internet modem/router. It is also used e.g. in hospitals.

Huub Schuurmans's picture

How are the data transmitted?

The data are transmitted using radio waves at a frequency of about 2,4 GHz at the nodes, where you can log is (the interlinks between nodes use a frequency of about 5 GHz). In fact there are several channels available (in Europe thirteen). However, these channels are partly overlapping. The 2,4 GHz band is a 'free' frequency, which implies that you do not need a license to use it. The only restriction is the maximum transmission power (100 mW maximum). This is very low (a thousand times less than eg. gsm or umts or the power that radio amateurs are using). This is one of the reasons that you need a 'line of sight' between sender and receiver.
Huub Schuurmans's picture

How fast is a connection via the Wireless Leiden network?

There is a distinction between the velocity on the local Wireless Leiden network and the velocity when using the Internet. The users of Wireless Leiden connect to the network using the so called 802.11b protocol, which nominal bandwith is 11 Mpbs, the nett data velocity will be 4 to 5 Mbps maximum to the access point.

The bandwith to other parts of the network, via the interlinks between the nodes, depends strongly on the data traffic (number of users), the number of hops and the occurrence of interference. For the experienced Internet bandwith there is an additional limitation of the gateway (proxy) internet connection and the number of users of that same connection.

Huub Schuurmans's picture

What is the desired height of a node location? The higher the better?

The short answer is: five to ten stories is nice. The long answer:

The optimum height depends on both the desired coverage and capacity and the local density (number of nodes in a certain area).

If a node (accesspoint) is put on a high roof, it covers a large area. The coverage is good. This kind of nodes are preferrably in the starting phase of a network: large number of potential users, sufficient capacity (not many users yet). However, every accesspoint can only serve a limited number of users, otherwise the bandwidth is reduced. If the number of users in a certain area increases you have to do something about this. If there are still frequencies (channels) available you could add accesspoints at this same location, using the free channels. But the number of channels that can be used per node is limited to 3 or 4 (and some maybe used for interlinks with other nodes).

The only way out is to 're-use' the same channels by adding new nodes at a different location. Wehave to take care, however, that these additional nodes are at a relatively low location, to avoid interference.

When the network grows and the number of users increases, we need more and more nodes at ever lower locations. Ultimately this could mean that at some point in the development of the network we have to take down a node at a high location. We therefore use the high locations preferrably NOT as a public accesspoint but only for interconnections. A good example is Node SOM on the Escher tower, the highest building in Leiden.

Huub Schuurmans's picture

I like to offer a location for a node, would Wireless Leiden be interested?

Yes, in principle we are interested in new locations. Wireless Leiden wants to expand the network and improve the coverage and new locations may be interesting. Especially high buildings in the suburbs are of interest and lower locations in the city centre where we want to improve coverage at street level for mobile users.
Huub Schuurmans's picture

Is Wireless Leiden a company? Does Wireless Leiden make a profit?

Is Wireless Leiden a company? Does Wireless Leiden make a profit?

Nope, Wireless Leiden is a non-profit Foundation, the work is done by unpaid volunteers. Wireless Leiden wants to facilitate a wireless computer network set up and maintained by a community of volunteers, businesses and organizations in the City of Leiden and surrounding municipalities. The Foundation has been established in August 2002.
Huub Schuurmans's picture

Where can I find the old 'news' items?

Where can I find the old 'news' items?

In the newsarchive on this site:
Huub Schuurmans's picture

Is it safe to use the Wireless Leiden network?

In principle the use of the wireless network is as safe as the use of Internet, i.e. NOT .

It is possible though - like on the Internet - to safeguard your data by using encryption techniques. With software encryption and securing your hardware your data and operating system can be made as secure as when you use an Internet connection.

Security is the user's responsibility! Wireless Leiden is not responsible for any harm in whatever shape or form resulting from or related to the use of the network.