400m link?

proteus

Hi all,

I'm thinking of linking two houses together over a wireless link. The houses are about 400m apart and do not have good line of sight as there are 3 or 4 narrow rooftops in the way. I don't know if this is possible but I was going to try the following setup:

A PC at either end running linux with a wireless pci card. A high gain directional antenna at each house pointing to the other antennna. I would really prefer to mount the antenna inside the roofs of the houses. At each antenna, the closest obstructing roof is about 90m away.

Questions:
How big a problem could Line of sight be in this situation?

Are there any health/ethical/legal considerations in pointing a high-gain antenna (standard commercial stuff) at someone else's house?

I'd appreciate any advise ye may have.:D

astec123

only think I would say is interference. You never know what those pesky neighbours will do. Our neighbour has a duff part for his TV setup and so we end up with a bad reception if he uses that aeriel, we asked to replace it for him, no charge to him and get someone in to do it he refused. So just to say you would probably want to ask the neighbours first if they have any objections and clarify that it wont do anything to their equipment whatever it may be and if it does you will make it so it doesnt. Last thing you need is them getting fussy and installing something to stop your network running because they cant get RTE or whatnot.

ethernet

At work, the broadband connect [from Irish Broadband ... cough ...] is routed to the modem around 100 m away. Meant to be a 2 meg connection. Usually get between 400 k to 1.2 meg. All the cars in the car-park can't help. Using a Linksys gear. The router is over 60 feet up in the air!

proteus

IBB:

ethernet wrote:

Meant to be a 2 meg connection. Usually get between 400 k to 1.2 meg.

Wow, 400k from IBB. That must be a first. I had an IBB connection about two years ago but I dropped them because they were utter crap. I don't think my new wireless setup could interfere with theirs but if it did, they could ring me and ring and ring and ring... I could then take a message and promise to call THEM back;)

Ziycon

ethernet wrote:

At work, the broadband connect [from Irish Broadband ... cough ...] is routed to the modem around 100 m away. Meant to be a 2 meg connection. Usually get between 400 k to 1.2 meg. All the cars in the car-park can't help. Using a Linksys gear. The router is over 60 feet up in the air!

Cat 5e can go a max. distance of 100m on its own, the greater the distance the more likely you are to lose connectivity at the client end or decrease it!

proteus

Ziycon wrote:

Cat 5e can go a max. distance of 100m on its own, the greater the distance the more likely you are to lose connectivity at the client end or decrease it!

Yes, but we're talking about a wireless link over distance not a wired link.

ethernet

proteus wrote:

Yes, but we're talking about a wireless link over distance not a wired link.

That's right. Can that distance limit of 100 m be increased by use of a repeater [I think that's what it's called]?

proteus, you rebel! Fair play. Too many Irish people just accept what is, to be blatently honest, an UNacceptable service. Can't complain, though -- it's free at work as we're considered a charity! The contention ratio must be like 50:1!

zenith

I had a Buffalo 802.11b lan bridge connection running using an omni and a directional about 400m for three years down a street and nae problems ...

People in the double decker busses would occasionally complain about headaches, tho'. Heh.

proteus

ethernet wrote:

That's right. Can that distance limit of 100 m be increased by use of a repeater [I think that's what it's called]?

In the wired world, repeaters are seldom used these days. Its far more common to use fibre links over distance. There are other technologies for transmitting data over a distance such as radio and laser but these are expensive and although home-made versions of these can be made e.g cantenna etc, I want to use off the shelf parts.

ethernet wrote:

The contention ratio must be like 50:1!

IN IBB parlance that means 1 out of every 50 connections works!

zenith wrote:

I had a Buffalo 802.11b lan bridge connection running using an omni and a directional about 400m for three years down a street and nae problems ...

Did you have any buildings obstructing the line of sight though?
I have several rooftops in the way and one house is on lower ground and just below the horizon.

Peanut

It's unlikely that it will work reliably with two antennas indoors at that range.

Very difficult to tell, but if at least one antenna was outdoors it would hugely increase the prospects of a successful connection.

PauloMN

Questions:
How big a problem could Line of sight be in this situation?

Are there any health/ethical/legal considerations in pointing a high-gain antenna (standard commercial stuff) at someone else's house?

Problem is you never know how this will work until you try it. Getting both antennas outside though is the key, on short poles clear of the roof apex. What you suggest should work fine (two high-gain directional antennas) but all that kit will cost a few quid and will mean either you or someone else doing some roof walking.

Remember you need to keep the cable runs from the antenna to the PC as short as possible and use good (expensive) quality cable.

There's no health issues other than falling off the roof...

No legal issues either if the antenna doesn't infringe on planning laws (it won't unless it's mounted at some ridiculous height). No need to talk to your neighbours either, unless you're going to put an antenna up on a shared chimney or something like that.

kdouglas

*cough http://www.wifi-shootout.com/ *cough

proteus

PauloMN wrote:

Problem is you never know how this will work until you try it. Getting both antennas outside though is the key, on short poles clear of the roof apex. What you suggest should work fine (two high-gain directional antennas) but all that kit will cost a few quid and will mean either you or someone else doing some roof walking.

Remember you need to keep the cable runs from the antenna to the PC as short as possible and use good (expensive) quality cable.

There's no health issues other than falling off the roof...

No legal issues either if the antenna doesn't infringe on planning laws (it won't unless it's mounted at some ridiculous height). No need to talk to your neighbours either, unless you're going to put an antenna up on a shared chimney or something like that.

Thanks Paulo. Thats good to know.

kdouglas wrote:

*cough http://www.wifi-shootout.com/ *cough

Where can I buy me one of those 12 foot satellite dishes?:D

ethernet

Netgear claim their Pre-N devices are better than that of Linksys [well they are likely to say that, aren't they?].

I was reading the manual of a Netgear wireless router that I want to buy. It says it's ideal for wireless connectivity for up to 400 m, just to your luck!

I would try Pre-N as opposed to just 54 Mbps gear for this operation, though.

Peanut

ethernet wrote:

I was reading the manual of a Netgear wireless router that I want to buy. It says it's ideal for wireless connectivity for up to 400 m, just to your luck!

400m outdoors though...

SouperComputer

what about sticking uni-directional antenna' raised up on a pole attched to say a chimney to get better line of sight?

proteus

SouperComputer wrote:

what about sticking uni-directional antenna' raised up on a pole attched to say a chimney to get better line of sight?

I was hoping to get away without doing this. The project is starting to sound doubtful considering the differences in elevation between the houses and having to "punch" my signal through a number of houses along the link. I couldn't have that on my conscience, there are enough funny looking kids in my area as it is...

Peanut

The problem with walls/roofs is that they really absorb a lot of the RF energy, also they may reflect the signal to an extent and generally distort it.

If you can find upstairs windows in the houses in the right direction, that might be enough. Your best bet would be to get a loan of equipment and test it out first.