[Dorset] Long range wireless network
Dear list- Since I can't get any ADSL in my new house, I need to try and share my parents' ADSL. They live about 800m away, within line of sight. Ideally I want to do this with a point-to-point wireless bridge. I believe that a couple of Linksys WRT54G units with OpenWRT are the best bet for the hardware, and then a couple of suitable antennas. I already have a 3com rod type antenna (somewhere around 75cm long I'd guess, from memory) which might do for one end. For the other end, I saw that commercial yagi type or directional patch antennas are available at reasonable prices [1]. I did keep an old Sky dish in case that was useful - and I found an article about it here http://www.trevormarshall.com/biquad.htm but it looks quite involved. There are also the cantennas and WokFi methods. I'm not especially clever on RF stuff and I know a few people on the list are. Can anyone advise? Has anyone set something similar up? Best regards, John [1] For example, http://www.wifi-antennas.co.uk/index.php?target=productsproduct_id=20 -- Next meeting: Bournemouth, Wed 2010-02-03 20:00 http://dorset.lug.org.uk/ http://www.linkedin.com/groups?gid=2645413 Chat: http://www.mibbit.com/?server=irc.blitzed.orgchannel=%23dorset List info: https://mailman.lug.org.uk/mailman/listinfo/dorset
Re: [Dorset] Long range wireless network
John, I have found these guys useful too. They also do a range of 5GHz stuff. http://www.solwise.co.uk/wireless-outdoorantenna-24.htm You can also brew your own ;-) Si On 01/02/2010 14:38, Tim wrote: On Monday 01 February 2010 14:08:54 John Carlyle-Clarke wrote: They live about 800m away, within line of sight. Ideally I want to do this with a point-to-point wireless bridge. Have a look at these guys http://www.wifi-antennas.co.uk/index.php?target=categoriescategory_id=209 -- Next meeting: Bournemouth, Wed 2010-02-03 20:00 http://dorset.lug.org.uk/ http://www.linkedin.com/groups?gid=2645413 Chat: http://www.mibbit.com/?server=irc.blitzed.orgchannel=%23dorset List info: https://mailman.lug.org.uk/mailman/listinfo/dorset
Re: [Dorset] Long range wireless network
On Monday 01 Feb 2010, John Carlyle-Clarke wrote: I'm not especially clever on RF stuff and I know a few people on the list are. Can anyone advise? Has anyone set something similar up? I've never set this up, but there are a couple of things that apply to any RF comms link. If you look at this page: http://en.wikipedia.org/wiki/IEEE_802.11, you will see that the band occupied is just above 2.4 GHz and the modulation scheme used is spread spectrum. This has quite a few benefits and some disadvantages. The main benefits are: 1. A very small antenna can be focussed very tightly at these frequencies, so your yagi doesn't have to be enormous. 2. The spread spectrum modulation scheme allows for channel overlaps, as shown in the diagram, without adjacent channels interfering with each other under normal circumstances. The disadvantages are: 1. The system is very definitely line-of-sight and the presence of walls trees etc can have a big impact on range. You might have to get your two antennas up onto masts to get sufficient signal and that will mean a good length of high quality coax at both ends. 2. If your signal strength is still a bit low, you might get adjacent channel interference, (notwithstanding the use of spread spectrum), because the energy from the sidebands of a strong signal close in might be greater than the energy from the sidebands of your wanted signal. Provided the area where you live isn't too populated you may be able to find a clear channel, but I suspect that you might have to retune now and then as other users jump into your chosen channel because (to them) your signal is quite weak. This latter problem may not manifest itself, but as I understand it, when a WiFi is set up through a repeater, the channel frequency has to be fixed, leaving the potential for problems later, as I describe. Others may be able to confirm or refute aspects of what I've said. -- Terry Coles 64 bit computing with Kubuntu Linux -- Next meeting: Bournemouth, Wed 2010-02-03 20:00 http://dorset.lug.org.uk/ http://www.linkedin.com/groups?gid=2645413 Chat: http://www.mibbit.com/?server=irc.blitzed.orgchannel=%23dorset List info: https://mailman.lug.org.uk/mailman/listinfo/dorset
Re: [Dorset] Long range wireless network
On Mon, 2010-02-01 at 17:21 +, Terry Coles wrote: On Monday 01 Feb 2010, John Carlyle-Clarke wrote: I'm not especially clever on RF stuff and I know a few people on the list are. Can anyone advise? Has anyone set something similar up? . This latter problem may not manifest itself, but as I understand it, when a WiFi is set up through a repeater, the channel frequency has to be fixed, leaving the potential for problems later, as I describe. Others may be able to confirm or refute aspects of what I've said. -- Terry Coles 64 bit computing with Kubuntu Linux I remember from a long time ago seeing some experiments that these guys at Flight Refuelling did. Here's an update with links to (probably) the old articles: http://www.frars.org.uk/cgi-bin/render.pl?action=linkurl=1058goback=0 My thoughts from being involved with Wireless ages ago are that the losses of long leads to the antenna are great, and it's better if you can mount the AP or Bridge close to the antenna and still be within the 10BaseT range of the switch. Probably means running Voltage up the pole too unless it supports Power over Ethernet. Depending on distance, would mean a boosted power supply to overcome losses. There also used to be companies around that sold repeaters that worked on 2.4GHz, but didn't have the full Protocol stack of 802.11, in order to get bit rates up. Thought about a laser repeater? Peter -- Next meeting: Bournemouth, Wed 2010-02-03 20:00 http://dorset.lug.org.uk/ http://www.linkedin.com/groups?gid=2645413 Chat: http://www.mibbit.com/?server=irc.blitzed.orgchannel=%23dorset List info: https://mailman.lug.org.uk/mailman/listinfo/dorset
