jimcarree

a few friends and me are plannign to set up a 'across town' wireless network, attatched is an image ive made up showing a map of locations.

all points have line of sight to the central point

central point is on a hill, 65m above sea level

all other points are on flats

so, being new to this, are we going about it the right way? what size aerials would you reccommend we use?

boosters?

what kind of speeds would we expect?

anything else we should know?

http://www.wirelessforums.org/attach...1&d=1141549260

miketoy

Looks like a great network if you have line of sight. The problem with 2.4Ghz RF amps is that they tend to amplify the noise as well as the signal. You would be best to use higher powered AP's like the Senao 200mW ones and then you could save money on smaller antenna and have a more reliable network. You would have to work out your horizontal angle of the spread of clients and see if a sector antenna would cover them. A 12 or 15dBi omni would work if you didn't mind all the wasted signal going behind the site.

idialman

cool, thanks for the reply. we have now bought a hills waveguide, a 25dbi parabolic grid antennas at the 2 furthest sites (2 & 4), and a 19dbi parabolic grid at site 3, hope fully this works a treat. we wont be using any boosters at this point.

does that sound alright?

jimcarree

just an update on progress, i have got the antenna up at location 4 (the furtherest) and can connect at 5mbit using just my laptop's internal antenna to the central point.

tomorrow will be intersting when we put up the waveguide

miketoy

ok, now we have all the sites up and running, howevr it seems quite slow to me, from the central poiint to my location (location 4) we only get aout 250kb/sec of data transfer,

yet to point 3, it gets around 2000kb/sec.


any1 shed any light on the situation?

idialman

is that KB or Kb? Big difference in measurement

Congrats on getting it up and running though

jimcarree

I'd probably start looking for sources of interference between your end and the central AP. I'm having a similar problem with some clients on my network at the moment due to noise.

What AP hardware/software are you using?

miketoy

all are using D-Link 2100's apart from one wihch is runing a linksys wet54g,

it makes no performance difference if all are dlink 2100s as we have borrowed another to test.

cables are all the cable that comes attatched to the antenna, some are plugged directly into the AP's, others have a dick smith pigtail. the center point and location 4 both have the antenna plugged directly plugged into the ap.

im not familier with the term RTS, nor am i aware of how to reduce packet size

jimcarree

The RTS (Request To Send) and fragment size options can be found on the Advanced page under Performance in the web config of the 2100. Try reducing these a bit and see if it makes a difference. The default RTS setting of 2347 essentially disables it. This will need to be configured on all clients to make it work effectively.

Also disable turbo mode if you are using it, it isn't very reliable on long distance links and increases the amount of noise you generate and receive.

Another option that sometimes helps is setting the preamble mode to short.

One question I do have is, do you run them in client mode talking to a standard AP? If so, connecting a client AP to more than one PC via a switch will cause all sorts of performance issues as it isn't supported by 802.11 standards. In this situation setting the access points in Point-to-Multipoint bridge mode should give you a noticable increase in performance.

Hope this helps

idialman

Hi there, What AP's did you use in the end. One solution might be to turn on RTS so that the central AP will poll each client in turn so there is not so many collisions. Also I would lower the packet size or "fragmentation" so the impact of errors is not so high with re-tranmissions.
Have you used a good quality short coax cable on your main AP? as this can make all the difference.
Good luck