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Poor Performance with WAP54G Repeaters

Discussion in 'Other Linksys Equipment' started by JCCorp, Nov 9, 2007.

  1. JCCorp

    JCCorp LI Guru Member

    Hi ALL,

    I seem to be experiencing VERY poor performance with my recent Point To Point setup.

    Home 1 = Internet/Server's --> Netgear Gigaswitch -->WAP54G(Access Point)

    Home 2 = WAP54G (Repeater Mode) -->Cat5e to Laptop

    BOTH WAP54G's are connected to TP-Link 14Dbi Outdoor Yagi-Directional Antenna's (http://www.tp-link.com/products/product_des.asp?id=62).

    BOTH WAP54G's have HyperWAP v3.04/v1.0c

    BOTH WAP54G's have the Outdoor Antenna's connected to the Right port of the AP's.

    Authentication Type: Open System(Default) Shared Key
    Basic Rates: ALL
    Transmission Rates: Auto(Default)
    CTS Protection Mode: Disable
    Frame Burst Mode: Enabled
    Tx Antenna: Right
    Rx Antenna: Right
    Tx Power: 84(Default: 42, Range: 0 - 84 )
    Beacon Interval: (Default: 100, Milliseconds, Range: 20~1000 )
    DTIM Interval: (Default: 3, Range: 1 - 255)
    Fragmentation Threshold: (Default: 2346, Range: 256 - 2346)
    RTS Threshold: (Default: 2346, Range: 256 - 2346)

    Hope this is enough information. As for the distance between HOME 1 & 2 it's about 300m ROUGH. Has perfect LOS (Line Of Sight) no tree's buildings, etc..

    At the moment the max speed i'm getting is about 800-850 KB/s (4Mbps) which i think is very poor. Can anyone please tell me what i'm doing wrong or something to try and improve things ?. I have scanned the area and there is only two other Wi-Fi devices in the area and both of them are on Ch 1, I have set mine to Ch 6.

    Also seems that it's loosing the connection atleast once every 24hrs and sometimes it will by itself just re-establish the Wi-Fi link and sometimes it doesn't ?.

    Sorry for the long post !!

  2. JCCorp

    JCCorp LI Guru Member

    Sorry forgot to add am using LMR200 cable. At Home 1 it's about 15 meters of the stuff and at Home 2 about 80cm.

  3. HennieM

    HennieM Network Guru Member

    Has the WAP got a Wireless Ethernet Bridge (WET), or perhaps a Client or Client Bridge mode? If so, give that a try on Home2's WAP. I don't know what the Repeater mode entails, but I think that you may be incurring additional overheads related to repeating the wireless signal, which you don't need as your laptop is wired to the WAP.
  4. JCCorp

    JCCorp LI Guru Member

    Yes my WAP54G v3's have Wireless Bridge Mode. But i tried that before and it didn't work, although i was still having alignment issues with the Point To Point. But your point about the overheads sounds right, i'll try and do a little bit of research on it.But even on Repeater mode the speeds should surely be higher ?
  5. JCCorp

    JCCorp LI Guru Member

    Right have managed to get thrm working together in BRIDGE mode both WAP54G's. But no improvement with the speed still only about 800ish KB/s which i work out to be just short of 4Mbps. Surely this should be much higher ?. It's only about 300-350m between each point with no trees or anything in the way.
  6. HennieM

    HennieM Network Guru Member

    Grabbing at straws here - are your security settings, etc., exactly the same on the 2 units, If you are using encryption, try WPA with AES, not WEP and not TKIP. Try lowering your Tx power to like 10mW or even lower - I don't know if such a thing exists, but you may be saturating the receivers blasting them with about 33 dB.
  7. JCCorp

    JCCorp LI Guru Member

    Yes both are using 128Bit WEP security settings. I was told that we as in the people with WAP54G's can't have WPA encryption in Bridge Mode ?. As for lowering the Tx Power i thought of this, but was scared that i'd loose the connection. But i'll give it a try.
  8. HennieM

    HennieM Network Guru Member

    I would not know which scheme you can use and which not. I'd suggest you perhaps try lowering the Tx power first on the near WAP - if you lose connection you are right by it to up the Tx power again. If that still works, do the far one. If all still Ok then change the far one to WPA/EAS (and send the wife over there in case it does not work, or you will get really fit... ;) and then the near one.

    I've seen cases where WPA does not work with WDS, but I have very little experience with bridge mode, so I dunno. If I'm not mistaken you could also have one WAP in AP mode, and the other in bridge mode - perhaps that's another thing to try. (Looks like you'll be getting fit after all... ;)
  9. JCCorp

    JCCorp LI Guru Member

    I tried lowering the Tx Power from 84 to 42 on each of the WAP54G's. But only made things worse. Transfer speeds went down from 800-8500 KB/s to 100-150 KB/s
  10. HennieM

    HennieM Network Guru Member

    As I'm all out of ideas, I had a look at the antennas you linked to in your 1st post - the TL-ANT2414A (1st attachment) is not a Yagi from what I can see! (Or it's the strangest Yagi I have ever seen...) It looks like a flat panel or patch antenna. Flat panel/patch antennas should be facing each other like in the 2nd attachment. A Yagi usually looks like the 3rd attachment.

    So, are your antennas facing each other? Also, both antennas should be upright, i.e. the lead wires pointing down - not one tilted 90 deg. or so, as this screws up the polarity of the signal.

    Also, the specs for the TL-ANT2414A mentions "VSWR: 1.92 max." This is a really bad VSWR (Voltage Standing Wave Ratio). You want the VSWR to be as near as possible to 1, but at least (IMO) less than 1.4 over 2.4 -2.5 GHz. I'm no expert, but I think that means you are sending and catching a lot of noise and stray frequencies; i.e. your signals are not clear, which is why you need such a high Tx power to get any signal whatsoever.

    You could also try to switch to channel 1 or 11 (13 non-US) as some antennas have better VSWR at a lower/higher frequencies.

    As the Tx power made such a huge difference, I'm thinking maybe your cable(s) are also not well connected perhaps. Did you use the proper connectors to join the cables to the AP and other joints, and are the little pins inside the connectors properly crimped?

    To give you an idea: I tested over about 300m down my street a year or so ago. Can't remember the exact numbers, but I did get a 1 or 2 Mbps conection with 2 WRT54Gs with the standard 2dBi antennas at 24 or 42mW. When I added parabolic reflectors made from Coke cans (the home made version of http://www.usbwifi.orcon.net.nz/alfawind.jpg) I think that signal went to 18 Mbps or better. My reflectors added in the vicinity of 6 to 7 dB.

    Edit: Also have a look at http://www.swisswireless.org/wlan_calc_en.html - look at the cable losses (although they don't have LMR200), the Fresnel zones, etc.

    Attached Files:

  11. JCCorp

    JCCorp LI Guru Member

    Hennie: THANK YOU VERY MUCH. You have given me lots to look at. I'll start by changing those cheap nasty antenna's. And try and reduce the LMR200 cable length at Home 1 as it's about 15m of the stuff. Where as if i mount the WAP54G in the loft it would reduce to about 1.0-1.5m in length.

    Again thank you very much !!!
  12. HennieM

    HennieM Network Guru Member

    No prob JCCorp. Hope you get sorted.
    Watch out for too much heat in the loft.
  13. JCCorp

    JCCorp LI Guru Member

    Hennie: This is England, It's bloody FREEZING !! ;)
  14. JCCorp

    JCCorp LI Guru Member

    Forgot to ask 2 things. One you might be able to answer and the other maybe not.

    1) The Link keeps on dropping everyday almost and can stay down for quiet a few hours, Do you have an idea of why ?

    2) Can you recommend a Panel Antenna 12dbi min that i can get in the UK ?


  15. Toxic

    Toxic Administrator Staff Member

    just remember when using devices in WDS/repeater mode the bandwidth is halved for each device you add.
  16. JCCorp

    JCCorp LI Guru Member

    Toxic: So because i have 2 WAP54G's in Bridge mode i have to half the advertised bandwidth of 54mb = 27mb ?
  17. Toxic

    Toxic Administrator Staff Member

    Remember radio signals have a transmit and receive. the 54mbs is maximum throughput in total (AFAIK) of both TX and RX.

    54mbs is really 27mbs one way. however in real world test average is approx 22-24mbs one way.

    so, adding a WDS device will bring this down to 12mbs (one way) then adding another wds device will bring this down to 6mbs one way.

    then dont forget, this is with only one wireless device, say a laptop on the wireless cell. this 6Mbs is SHARED with any other wireless device so two laptops share the 6mbps throughput.

    hope this explains it somewhat.
  18. HennieM

    HennieM Network Guru Member

    Don't know why your connection would drop at times. Maybe if you have the antennas sorted, it will be better.

    I have no clear idea where you could get antennas. I see http://www.poynting.co.za/ distributes to http://www.rfip.eu/ in the UK. I have a 14dBi patch - this one's http://www.poynting.co.za/productdisplay.php?id=87&cat_id=3 predecessor - from Poynting, and found it good. I am no antenna expert, but I know you should check the VSWR, weather resistance, beam width, etc. in addition to the dB when you buy. (For your application I would think the beam width can be pretty narrow.)

    You could also try making your own waveguide cantenna (http://www.turnpoint.net/wireless/cantennahowto.html , http://bloggedopinions.blogspot.com/2005/11/how-to-build-cantenna.html , and many other), but I found it much less trouble to just buy it. Cantennas I've made give me between 8 and 16 dBi, but it's not so easy to weatherproof and mount. (The 16 dBi one has huge cone on it.)

    No, your bandwidth would not be halved in WET or client/client bridge mode, just in WDS mode. However, the best transfer speed you'll get out of a wireless bridge like yours would probably be around 26Mbps or 3.1MB/s. This is because wireless, unlike wired, has a lot of overhead it carries with the data.

    Edit: Oh, I see Toxic explained the bandwidth thing while I was typing.
  19. JCCorp

    JCCorp LI Guru Member

    I know that this might be a stupid question, but thought there's no harm in asking. At Home 2 i've just proped up the antennta against the window INSIDE the house, BUT the windows are Leaded. Will this affect the signal ??
  20. HennieM

    HennieM Network Guru Member

    Leaded windows most definitely can influence your signal. However, "how much, if anything at all?" is an open question. To give you an idea, I found a mirror to take a couple of dB off a signal - that's close to half the power.
  21. JCCorp

    JCCorp LI Guru Member

    Wow. Thought it might affect it, but didn't realise it could reduce the Db that much.
  22. JCCorp

    JCCorp LI Guru Member

    Have reduced the Antenna cabling from 15m to about 3m and this has made a big difference. Has increase KB/s from 300-400 to 800-900

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