View Full Version : Wireless gear - best for between two buildings?

24-04-2004, 11:29 PM

Im possibly doing a job for a client who wants Wireless gear setup between two buildings. The rooms are likely 50m away and will probably have two concrete walls between them.

They're going to want an Adsl router with wireless connectivity too.
They have laptops that use 802.11g, which IIRC is able to switch between 802.11a or b networks?! Correct?

What router would be best? How fast is it likely to be (Anything 1mbps or over should suffice, as long as there are no lost packets...

I have til 9am tomorrow to find a router and email them the details.



25-04-2004, 12:19 AM
Hi Chill, have a look at some of the Linksys routers/access points. They're an off-shoot of Cisco now aren't they?

Not sure on the ranges of those, but you might get more range by putting the routers near a window or something.

25-04-2004, 12:25 AM
Well current wireless networks are said to have a max range of 100-150ft indoors. So thats 45.72m, and yours is outdoors too...

25-04-2004, 12:26 AM
50 metres .... + (reinforced) concrete walls ....

You need a miracle, not a router.

25-04-2004, 12:33 AM
802.11g is compatible with 802.11b, but not 802.11a. I also believe there is another standard coming along soon (*sigh*).

I'd suggest to find out technical details of the wireless capabilities of the routers you're looking at, such as signal strength, whether the antennae is/are moveable, etc.

A signal booster might also be necessary, since it would be going through two concrete walls that are a fair distance apart (I should think that where it would fall short is after going through the second wall - it should be fine up to a certain distance for the first one). Perhaps directional antennaes would also be better suited to the job.

US Robotics have some good products, such as the SureConnect 9106 (http://www.ascent.co.nz/mn-product-spec.asp?pid=119687).

25-04-2004, 10:15 AM
They've emailed me telling me to email them back at 12... So any other ideas?

That was my thought.... :-(

I'll take a look at that... Antennae looks like the way to go

Cheers, I'll check 'em out :-)

Are there any other routers that might be good for the purpose... Bigger antennae for everybody?


25-04-2004, 10:32 AM
>>802.11g is compatible with 802.11b, but not 802.11a. I also believe >>there is another standard coming along soon (*sigh*).

Nothing wrong with that.. on one hand you've got wimax which offers a 30mile coverage, up to 76 (ish) mbit connectivity, you dont need LOS either. On the other hand you've got 802.11.n which brings in a whole raft of features and IIRC 108mbit connectivity.

.n backbones and wimax nodes sounds great to me

To answer the original question:
You wont need much power to do a 50m connection, you could use a bridge at either end and connect them to directional panel antennas. You wont need much gain to do 50m

Perhaps you should ask on the nzwireless.org forums?

John H
25-04-2004, 10:38 AM
My office is a tin clad "Gottage" made by Skyline. I have an external antenna set up on its verandah post to communicate with the other part of the WLAN inside the house. Without the external antenna I used to have no end of trouble with dropped packets etc because the signal could not cross the tin cladding.

With the external antenna I got excellent connection until some nasty neighbour introduced some interference into the ether and now my WLAN just drops connections all the time.

However, the external antenna was all the go until the neighbourly interference (probably a 2.4Ghz phone or a competing WLAN). My external antenna is sited horizontally rather than vertically. For some peculiar reason it works far better that way - if you set up something like it, you may like to experiment with the orientation.

My WAP is a Linksys WAP11 with a signal booster. The adapter in the house laptop used to be the matching Linksys PCMCIA adapter, but I have found that the el cheapo DSE USB adapter was better because it can be sited to get a better signal. I also thought that the PCMCIA card seemed to get very hot and towards the end of my use of it, it seemed unreliable.


25-04-2004, 02:18 PM
have you tried using different channels John H?

25-04-2004, 02:28 PM
You should use wires, faster, just not as easy to setup up.


John H
25-04-2004, 02:48 PM
>have you tried using different channels John H?

Yes, whetu, I have. I was on 6, so I tried 8, 11, then 1. Still no change.

Thanks for the suggestion.

John H

25-04-2004, 03:40 PM
By two buildings, do you mean high rise towers with two offices across from each other?

------ ------
| | | |
| |<-->| |
| | | |
| | | |
|__ |___ |__ |___

Or are they both on the ground floor?
------ ------
| | | |
|__ |<-->|__ |___

Because if they are on the ground level then a cable can easily suffice. Otherwise, I'd just use two bridges. Our school IT Technician and I were going to do this between our houses. We have line of sight, but are about 1km apart. My plan was to get a Wireless network card (I got the DLINK 108Mbps ones) and put it in an old computer which also has wired.
I was going to get a BIG antenna (Dlink Grid panel antenna - range of 10KM) and use the computer to act as a bridge. He would have the wireless access point and the same kind of antenna at the other end.

As far as routers are concerned, I presume you mean DSL routers, then pretty much any will suffice. If you dont mean DSL routers, then it is even more likely that any will suffice. But Cisco are good :D

25-04-2004, 09:29 PM
A group I do some work for was contemplating a wireless connection between two buildings with concrete block walls about 20 metres apart, but couldn't get it to work.
We found that the easiest test for practicality was to have a cordless phone base in one building then walk towards the other one while using the handset. Whammo! The phone worked perfectly while approaching the second building but died as soon as going inside. Hence wireless LAN (which uses the same band) was no go.

John H
26-04-2004, 09:57 AM
Did you try out the idea of an external aerial rodb? That is how I got through an offending wall...


Billy T
26-04-2004, 10:42 AM
> However, the external antenna was all the go until
> the neighbourly interference (probably a 2.4Ghz phone
> or a competing WLAN). My external antenna is sited
> horizontally rather than vertically.

If the interference is a telephone system, it will probably be vertically polarised so you may be able to reduce the interference effects by using external antennas at both ends of the link and trying horizontal or diagonal polarisation, choosing the one that gives the most reliable results.

Accuracy of alignment is very important for the best results, and there are two options for diagonal polarisation i.e. clockwise or anticlockwise. Your better experience with horizontal alignment may be due to the broader acceptance angle which makes accurate aiming slightly less critical.


Billy 8-{)

John H
26-04-2004, 06:40 PM
Hi Billy

Thanks for the hint Billy T. At the moment my wireless access point has two antennae, one vertical (internal) and one horizontal (external). I tried switching them both to horizontal, but unfortunately it hasn't changed anything. The usb adapter in the house doesn't have the facility for attaching an external antenna so I can't try that. Maybe I could try adopting another adapter that does, so as to try that out.

I don't know what it is that is so powerful as to disrupt the system like this. I have a Centrino laptop in the office almost next to the WAP, and even that one drops the network as well, and both the WAP and that laptop are less than a metre apart within a tin shed!

27-04-2004, 12:10 AM
They gave up and laid a lan cable instead!