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Wap200E with High Gain Antenna - Connection & Range Issues

Discussion in 'Other Linksys Equipment' started by gimlet123, Jun 15, 2008.

  1. gimlet123

    gimlet123 Addicted to LI Member

    Hello All

    I'm in Afghanistan with the Army and a group of us pooled up for Satellite Internet. I have set up a central WAP200E access point with the 9db High Gain Antenna at a height of about 15FT.

    The buildings here are wood with currogated Tin roofs. The signal quality of the AP is very low even when less than 100Ft away. What am I doing wrong with my setup. The literature of the Antenna said it has a range of up to 860M at 11mbs rate. So why is it that I'm having problems being less than 100Ft away.

    Also if you manage to connect with only 15 users the access point constantly drops connection or freezes to the point it has to be powered down in order to get back into the management console.

    I have updated to the latest firmware fron the Linksys website and that has not helped.

    I'm looking to cover user that are about from 50 to 150ft away from the AP.

    Please help this is driving us nuts, and it takes about a month to get anything here in the mail
     
  2. HennieM

    HennieM Network Guru Member

    What kind of antenna - Omni, or directional?
    How long your cable from AP to antenna?
    What cable are you using from AP to antenna - LMR400, RG58, etc.?
    What does the antenna's radiation pattern looks like?
    What is the antenna's SWR over the 2.4GHz spectrum?
    What kind of client makes the connection - another AP, PCMCIA cards, etc.?
    What does the signal have to go through at 100ft - Can the client card or client antenna "see" the AP's antenna?
     
  3. acejavelin

    acejavelin Network Guru Member

    All the information asked for above would be useful... but here are a few ideas that may help for now.

    1) Assuming this is an omni-directional antenna, lower it to about 6 ft, so it doesn't have to try to deal with the tin roofs, I live in a mobile home with tin walls, absolutely destroys the signal strength of any radio waves.

    2) Enable Wireless QOS (WMM) in the AP, to allow it to prioritize traffic.

    3) Try alternate Wi-Fi channels, use something like Netstumber (see #7) then change the AP's channel and test signal stength in various locations, continue to do this until you get the best signal strength.

    4) Try to keep the maximum number of SIMULTANIOUS users under 10-12. Might be tough under your circumstances, but would probably help to setup a schedule and rotate access to all users. If it locks at 15 and you know it, try to keep it under that number until a better fix comes along.

    5) Look for an after-market firmware like DD-WRT or something else, I am not sure what is available for this AP, but it is Linux based according to the documentation, so there should be something available that would allow you to increase the Tx power of the AP. (Someone could jump in here)

    6) Look for anything else that may be running in the 2.4Ghz spectrum that would be causing interference or things that cause signal blockage, examples would be: microwave oven, cordless phones, amatuer ham radio, certain types of glass, reinforced concrete, and more. Plus, if you are in a military installation who knows what else could be interfering, radar, military radio communications, and ?????? that may be out of your control.

    7) Lastly, try something like http://www.netstumbler.com/ load it on a laptop, and walk around with it running, you might find an area that has something that is lowering the signal signal significantly.

    The WAP200E doesn't have the best reputation for being of high quality and reliability, but hopefully some of these things can help because Circuit City, CompUSA, and Best Buy are probably not just up the road to get a replacement, and you guys have to make due with what you got.

    Good luck, and thanks for the job you guys are doing over there!!! :thumbups:
     
  4. gimlet123

    gimlet123 Addicted to LI Member

    I am using the Linksys 9dbi Omni Diectional Antenna that is suggested from their website.
    Here are some pictures of our setup to hopefully help you guys see what I might be doing wrong?

    Answer to the questions:

    1 - Omnidirectional Antenna
    2 - The cable looks to be like 2ft
    3 - Im using the supplied cable from Linksys. Not sure
    4 - Antenna radiation panel - Not a clue what you mean by that
    5 - antenna's SWR ?????
    6 - Clients connecting are laptops with Internal Wifi cards
    7 - Look at the attached picture, we have users in all 3 rows of housing.

    im sorry i could not give you better answers for some of your questions.
     

    Attached Files:

  5. HennieM

    HennieM Network Guru Member

    OK. Assuming that the cable and connectors to the antenna are good, that leaves only a few possibilities:

    1) An omni radiates in a horizontal donut around an antenna pointing up like yours. Thus, very close below (or above) the antenna, you'll have weak signal. With your closest client being 50ft away, I don't think that's an issue.

    2) The specs for the antenna should list an SWR (Standing Wave Ratio), denoted most often as VSWR (Voltage Standing Wave Ratio). This parameter can be a graph, or just a number like <1.5 (less than 1.5). You want this number to be as close as posible to 1. If you post the antenna model maybe somebody could check that for you.

    3) I see a lot of wood, a lot of tin roofs, and a lot of concrete blocks (the blocks between the houses). Wood is a signal eater. Tin roofs reflect signal, so if such a roof is between the omni and a laptop it will eat signal. Concrete also eats signal.

    Internal WiFi cards usually have crappy antennas to start off with. If you stand in the clear with a laptop, where you can see the omni, is the signal good? If so, these signal eaters are at work, so find a way for your laptops to "see" the omni.
    A way may be to put a directional antenna on each house's roof into which the laptops can plug. Laptops usually don't have such plugs, so you may have to put an access point - setup as a wireless client - in each house, and the laptops then plug into this AP by ethernet cable. An expensive option...

    4) If the "in the clear" test from (3) above still results in weak signal, you'll have to dig deeper into the AP, interference, etc. Start off with acejavelin's suggestion (3) - different channels.
     
  6. acejavelin

    acejavelin Network Guru Member

    Did a little digging on this antenna, I assume it is the correct one, it is the only Linksys 9 db gain antenna I could find, but it includes the specs that HennieM was looking for. Hope it helps.


    Specifications
    [FONT=Myriad Pro,Myriad Pro][FONT=Myriad Pro,Myriad Pro][FONT=Myriad Pro,Myriad Pro]Model: HGA9N [/FONT]
    [FONT=Myriad Pro,Myriad Pro]Ports: 1 N-type female connector [/FONT]
    [FONT=Myriad Pro,Myriad Pro]Cabling Type: Coax - 50 Ohm impedance [/FONT]
    [/FONT]
    [/FONT]Electrical Specifications
    [FONT=Myriad Pro,Myriad Pro][FONT=Myriad Pro,Myriad Pro][FONT=Myriad Pro,Myriad Pro]Frequency range: 2400 MHz - 2500 MHz [/FONT]
    [FONT=Myriad Pro,Myriad Pro]Gain: 9 dBi [/FONT]
    [FONT=Myriad Pro,Myriad Pro]VSWR: 1.92 : 1 Max [/FONT]
    [FONT=Myriad Pro,Myriad Pro]Polarization: Linear, vertical [/FONT]
    [FONT=Myriad Pro,Myriad Pro]HPBW / horizontal: 360º [/FONT]
    [FONT=Myriad Pro,Myriad Pro]HPBW / vertical: 11º [/FONT]
    [FONT=Myriad Pro,Myriad Pro]Max Power: 4 W [/FONT]
    [FONT=Myriad Pro,Myriad Pro]Impedance: 50 Ohms [/FONT]
    [/FONT]
    [/FONT]Specifications
    [FONT=Myriad Pro,Myriad Pro][FONT=Myriad Pro,Myriad Pro][FONT=Myriad Pro,Myriad Pro]Range: Maximum Outdoor range* - 120 m (0.078 mi) @ 54 Mbps, 880 m (0.55 mi) @ 11 Mbps [/FONT]
    [FONT=Myriad Pro,Myriad Pro]Dimensions: 75mm X 625mm X 56mm [/FONT]
    [/FONT]
    [/FONT][FONT=Myriad Pro,Myriad Pro][FONT=Myriad Pro,Myriad Pro][FONT=Myriad Pro,Myriad Pro]* Range estimation is based on one WAP54GPE Access Points with HGA9N antenna connecting to Wireless Client with 0dBi antenna under ideal line-of-sight conditions[/FONT]
    [/FONT]
    [/FONT]Environmental
    [FONT=Myriad Pro,Myriad Pro][FONT=Myriad Pro,Myriad Pro][FONT=Myriad Pro,Myriad Pro]Dimensions: 2.95" x 24.61" x 2.20" (75 x 625 x 56 mm)[/FONT]
    [FONT=Myriad Pro,Myriad Pro]Unit Weight: 0.44 lbs (0.2 kg)[/FONT]
    [FONT=Myriad Pro,Myriad Pro]Mounting Options: Mounting kit provided[/FONT]
    [FONT=Myriad Pro,Myriad Pro]Certifcation: FCC, IC[/FONT]
    [FONT=Myriad Pro,Myriad Pro]Operating Temperature: -22 to 176°F (-30 to 80°C)[/FONT]
    [FONT=Myriad Pro,Myriad Pro]Storage Temperature: -22 to 176°F (-30 to 80°C)[/FONT]
    [FONT=Myriad Pro,Myriad Pro]Operating Humidity: 5 to 95% non-condensing[/FONT]
    [FONT=Myriad Pro,Myriad Pro]Storage Humidity: 5 to 95% non-condensing [/FONT]
    Package Contents
    [FONT=Myriad Pro,Myriad Pro][FONT=Myriad Pro,Myriad Pro][FONT=Myriad Pro,Myriad Pro]Antenna body [/FONT]
    [FONT=Myriad Pro,Myriad Pro]Antenna Cable [/FONT]
    [FONT=Myriad Pro,Myriad Pro]Lightning Protector [/FONT]
    [FONT=Myriad Pro,Myriad Pro]User Guide on CD [/FONT]
    [FONT=Myriad Pro,Myriad Pro]Quick Installation Guide [/FONT]
    [/FONT]
    [/FONT]
    [/FONT]
    [/FONT]
     
  7. HennieM

    HennieM Network Guru Member

    The VSWR (<1.92) of this antenna is crappy, but it's workable I guess.

    This
    may be part of your problem. See the attached radiation pattern (shamelessly stolen from http://www.microwaves101.com/encyclopedia/Navy handbook/3.3 Radiation Patterns.pdf):
    Look at the ellipse, and imagine your omni-antenna is the Z-arrow, so you are looking at your omni as it sits on the pole. The strong signal of your antenna is now denoted by the ellipse, which is what you signal you "see" to the right and left of the omni. (Obviously this ellipse is just a cut-through of the "donut of strong signal" that sits around the antenna in all horizontal directions).
    The angle where the ellipse crosses the Y-line, is 5.5deg relative to the Y-line (11deg/2) in your case.

    Applying some geometry: With your omni being 15ft (about 5m) in the air, it means the bottom line of the ellipse crosses ground level at about 60m or 200ft. Thus, with your users being 50 - 150 ft from the antenna, your users may be in the area below the ellipse, and therefore in the weak signal area of the antenna.

    You could try lowering the omni to bring the users into the strong signal area of the antenna. Remember though, that the signal to users in far houses would then have to travel through more of near houses, concrete, wood, etc....

    I guess this omni was designed to sit near ground level, not high up on a pole... ;)

    Edit: Good explanation here: http://www.cisco.com/en/US/tech/tk722/tk809/technologies_tech_note09186a00807f34d3.shtml
     

    Attached Files:

  8. gimlet123

    gimlet123 Addicted to LI Member

    If I stand 200M away at one of my towers I can get 3 bars , so the antenna is definately radiating correctly I am guessing. I went ahead and ordered one of those yaji antennas with a repeater that I am thinking of using on my farthes points that ay I can then bring the access point on the pole and place it in between the rows and lower if you guys thinj it will help. Also a lot of the guys are ordering external cards with stronger antennas so I'm hoping that will solve most of the problen. Thank you guys.

    Even though you all gave me a head ache with the geometry lesson
     
  9. HennieM

    HennieM Network Guru Member

    If your omni is currently off to one side of the users, I'd rather suggest that you replace just the omni with a flat panel- or patch- directional antenna, still at 5m in the air. Flat panels and patches have horizontal and vertical radiation patterns spanning about 30deg.

    At 30 deg (15 down/15 up), a flat panel's strong signal reaches ground level at 21m or about 70 ft. As you have 15deg of strong radiation going to the heavens if the antenna faces exactly horizontal, you can also face the antenna down slightly, to bring the strong signal area closer to the pole.

    Changing to such an antenna would also give you a stronger signal to your users: with the omni you are blastig signal in 360deg around the 9dB omni. If you get a 9dB flat panel, it would be concentrating the same power in a much smaller area, resulting in better signal. (You might still have trouble getting user's signal to the antenna though).

    If you do this, CHECK, before you buy, that the radiatioin patterns are what you want. In the same breath, check that the antenna's VSWR is < 1.5 over the entire 2.41 - 2.47 GHz spectrum. (A VSWR as close to 1.0 as possible would give you the clearest signal).
     

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