+ Post New Thread
Page 1 of 2 12 LastLast
Results 1 to 15 of 21
Wireless Networks Thread, wireless / physics question in Technical; Our buildings are in residential areas, and are seperated by houses and other buildings. We cant link them with fiber ...
  1. #1

    RabbieBurns's Avatar
    Join Date
    Apr 2008
    Location
    Sydney
    Posts
    5,527
    Thank Post
    1,339
    Thanked 470 Times in 307 Posts
    Blog Entries
    6
    Rep Power
    199

    wireless / physics question

    Our buildings are in residential areas, and are seperated by houses and other buildings. We cant link them with fiber as its too expensive to dig up the public roads. So we use wireless directional antenna on the roofs with netgear bridges. (802.11g)

    From building A to B it works absolutely perfectly, and normal network usage it is almost impossible to tell that your not plugged in.

    But from building B to C, even though the signal strength is reported in the AP, packet loss is astranomical.

    The only thing different is that between B and C it goes over treetops and roofs whereas A - B is pretty clear.

    Am I correct in thinking the wavelength on 2.4Ghz is about 12.5cm? So should the trees and rooftops be having an effect?

    Its so unusable accross at building C its not funny.

  2. #2

    FN-GM's Avatar
    Join Date
    Jun 2007
    Location
    UK
    Posts
    16,044
    Thank Post
    888
    Thanked 1,727 Times in 1,490 Posts
    Blog Entries
    12
    Rep Power
    453
    Do you have anything else local operating on the same channel?

  3. #3

    Join Date
    Aug 2007
    Location
    Deal, Kent
    Posts
    343
    Thank Post
    12
    Thanked 73 Times in 51 Posts
    Rep Power
    27
    Quote Originally Posted by FN-GM View Post
    Do you have anything else local operating on the same channel?
    What i would suggest also. Ideally you would have 4 wireless stations creating 2 bridges.

    A Wireless to B on Channel x
    B wired to C
    C Wireless to D on Channel y

    Si

  4. #4

    SYNACK's Avatar
    Join Date
    Oct 2007
    Posts
    11,223
    Thank Post
    874
    Thanked 2,717 Times in 2,302 Posts
    Blog Entries
    11
    Rep Power
    780
    Trees are awful for wireless as like people they are full of water, 2.4ghz is a microwave frequency which is closely coupled to water and so lovely green leaves act as an impressively effective cone of silence for wireless traffic as the signals are absorbed rather than bounced. I suspect you may need to try and route the signal around the obsticals differently or use a more focused antenna that can be targeted directly at the receiver.

    Your other options would be to try using 802.11a ad it 5.something ghz band may be more resilient to both the obsticals and any electronic interference in the way or to use 802.11n with dual or tripil antennas on each side that can use multiple path and a wider frequency band to transfer the data.

  5. #5

    RabbieBurns's Avatar
    Join Date
    Apr 2008
    Location
    Sydney
    Posts
    5,527
    Thank Post
    1,339
    Thanked 470 Times in 307 Posts
    Blog Entries
    6
    Rep Power
    199
    Quote Originally Posted by Psymon View Post
    What i would suggest also. Ideally you would have 4 wireless stations creating 2 bridges.

    A Wireless to B on Channel x
    B wired to C
    C Wireless to D on Channel y

    Si
    Yup thats the excact setup. There are 2 AP's on building B, one at the front linking to A and one round the back on the side linking to C.

    Ive been through every channel on the B-C link to see if it makes a difference.

    We have a company coming tomorrow to demonstrate WiMax or something along those lines, but 11a and 11n is two of the other options I have been thinking along.

  6. #6
    Gerry's Avatar
    Join Date
    Jun 2007
    Location
    North Wales
    Posts
    431
    Thank Post
    60
    Thanked 38 Times in 35 Posts
    Rep Power
    24
    Check these websites out:
    What is the best WiFi antenna for me? | Do-It-Yourself Wireless Antennas Update
    Wireless - Technical Discussion Document

    Yup, anything that retains water is going to affect wi-fi signal. 5GHz band is much better, but will still suffer some degradation, and if you are going to use it, will have to be registered with Ofcom (for a small fee) as the military and emergency services also use the same band.

    I would recommend directional antennas, mounted on poles to have a clear line-of-sight, or you trim the trees back a little.

  7. #7

    Join Date
    Jan 2007
    Posts
    424
    Thank Post
    7
    Thanked 32 Times in 27 Posts
    Rep Power
    21
    YouTube - Heineken - Road works

    Have you waited for something like to happen?

    Kyle

  8. #8

    Domino's Avatar
    Join Date
    Oct 2006
    Location
    Bromley
    Posts
    4,168
    Thank Post
    217
    Thanked 1,280 Times in 798 Posts
    Blog Entries
    4
    Rep Power
    511
    why not ask a wireless specialist company for a survey...?

    Might be able to swing a freebie - there might be things you haven't considered....

  9. #9
    User3204's Avatar
    Join Date
    Aug 2006
    Location
    Wirral
    Posts
    769
    Thank Post
    55
    Thanked 66 Times in 62 Posts
    Rep Power
    34
    Laser costs about £3k - £5k, but this will start at 100mbps, you do need line-of-site.

    We have a 11mbit directional wireless, and found we had to trim a few trees to get the signal through, and if it really buckets it down, to the extent we can't see the building, neither can then wireless...

    I have been trying to get our SLT to approve replacing the wireless with something the kids don't aim footballs at, and fibre is the best option (for us), it's just not cheap.
    Other options I considered:
    a) an additional phone line with SDSL, that we could get a VPN through - but no SDSL in the area (apparently).
    b) pay the LA, who provide our Internet access, to link to it (at 8mbit), and let us have a straight VPN through - but they said no chance.
    c) fibre across the road - no-one was able to get me a price on a mole...

    Contact a local network cabling company to see what they can do, ask for a survey.

  10. #10


    Join Date
    Feb 2007
    Location
    Northamptonshire
    Posts
    4,692
    Thank Post
    352
    Thanked 797 Times in 716 Posts
    Rep Power
    347
    but no SDSL in the area (apparently).
    If you don't believe there's no SDSL provision given the apparently, check for yourself at Samknows.com.

  11. #11

    mac_shinobi's Avatar
    Join Date
    Aug 2005
    Posts
    9,789
    Thank Post
    3,296
    Thanked 1,054 Times in 975 Posts
    Rep Power
    365
    Quote Originally Posted by Psymon View Post
    What i would suggest also. Ideally you would have 4 wireless stations creating 2 bridges.

    A Wireless to B on Channel x
    B wired to C
    C Wireless to D on Channel y

    Si
    side tracking a bit but how do you create a wireless bridge ( presuming this is between 2 wireless access points ) or how do you do it exactly ?

  12. #12
    User3204's Avatar
    Join Date
    Aug 2006
    Location
    Wirral
    Posts
    769
    Thank Post
    55
    Thanked 66 Times in 62 Posts
    Rep Power
    34
    Quote Originally Posted by kmount View Post
    If you don't believe there's no SDSL provision given the apparently, check for yourself at Samknows.com.
    Samknows.com tells me there is SDSL service.
    But when I talk to actual phone companies, Redstone, BT, they can't tel me who... I suspect samknows.com knows about the LA connection, but this is somehow reserved by them, and not available to anybody else. Which is why I went to the LA and asks them about another connection, and they said no.

  13. #13


    Join Date
    Feb 2007
    Location
    Northamptonshire
    Posts
    4,692
    Thank Post
    352
    Thanked 797 Times in 716 Posts
    Rep Power
    347
    Without being facetious is your LA connection SDSL?

  14. #14

    john's Avatar
    Join Date
    Sep 2005
    Location
    London
    Posts
    10,619
    Thank Post
    1,499
    Thanked 1,053 Times in 922 Posts
    Rep Power
    304
    BT have services which allow you to link buildings together, enquire with them, they can do them for you for a price, Kilostream I think was one going back years ago that was popular for linking remote offices back to central ones, but it will no doubt have been superceded by now. They were all about direct P2P links though which would do the job you need.

  15. #15

    webman's Avatar
    Join Date
    Nov 2005
    Location
    North East England
    Posts
    8,406
    Thank Post
    640
    Thanked 961 Times in 661 Posts
    Blog Entries
    2
    Rep Power
    324
    Try pointing B and C antennas slightly to the side or above the trees; or both towards any other high buildings in line of sight of both sites - it might just bounce

SHARE:
+ Post New Thread
Page 1 of 2 12 LastLast

Similar Threads

  1. THe Wireless Question!
    By GrumbleDook in forum Wireless Networks
    Replies: 17
    Last Post: 29th May 2007, 10:12 AM
  2. help for new physics lab technician
    By pcprofessor in forum General Chat
    Replies: 6
    Last Post: 18th September 2006, 03:44 PM
  3. Really dumb wireless question
    By richard in forum Wireless Networks
    Replies: 11
    Last Post: 14th February 2006, 11:37 AM
  4. Wireless Access Point SSID Question
    By mseaney in forum Wireless Networks
    Replies: 14
    Last Post: 14th October 2005, 08:23 AM
  5. Odd Request from a Physics Teacher...
    By palmer_eldritch in forum Windows
    Replies: 3
    Last Post: 7th October 2005, 02:20 PM

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •