iMac has a fixation on Airport Express

Discussion in 'iMac' started by ParagJain, Nov 15, 2012.

  1. ParagJain macrumors 6502

    Jul 24, 2011

    My 2007 model iMac seems to have got a fixation on Airport Express and I can't seem to remove it.

    The setup I have is Modem hardwired to Airport Extreme, extended by Airport Express. The trouble is that iMac only connects to wifi when the Express is started and not otherwise. Both work on 5 Gz n band.

    I am able to connect my macbook and iPad to airport extreme when kept side by side to iMac, but iMac just doesn't do.

    i have reset both wifi devices, factory reset both devices, reset SMC and PRAM on iMac; I have also verified disk permissions etc.

    Any help is appreciated to help me connect the iMac back on Wifi.

  2. Transeau macrumors 6502a


    Jan 18, 2005
    Alta Loma, CA
    If I understand you correctly.... Your iMac is connecting to an Airport Extreme, that is farther away then the Airport Express..?

    If so, it's an easy explanation. The Airport Extreme has a more powerful radio, and the airport Express may be too close to the iMac. WiFi needs to be about 10 to 20 feet away to have a good clean signal. Too close and the it distorts.

    Think of it like this - Stand 2 inches from a bullhorn and it will be so loud that you can't hear it. Stand 50 feet away and it will be perfectly clear.

    Same thing here, your Express is too loud and distorted, so the iMac is picking the Extreme. It may be quieter, but at least it's clear.
  3. Omne666, Nov 15, 2012
    Last edited: Nov 15, 2012

    Omne666 macrumors 6502a

    Sep 16, 2010
    Melbourne, Australia

    I hate wireless networking, and your explanation is friggin awesome. Don't know how true it is but I love it. Logical. Even sensible. Learn something knew everyday I do!! :eek:

    Now, if you can explain to me why my pressed metal ceilings seem able to shorten the range of my wireless to just about the room it's in I'd be even more impressed. I have like 5 AExp's scattered throughout my house just to combat the absolute crappy range I get from each unit.
    (I actually have an idea from the movie Enemy Of The State, whe gene hackmans computer hole is surrounded by mesh fencing...dampens the signal and risk of detection from the outside....again, no idea if it's true, but I liked it)
  4. eagandale4114 macrumors 65816


    May 20, 2011
    Metals tend to block wifi signals. That's why the all aluminum unibody macs have a window for the wifi receivers.
  5. Transeau macrumors 6502a


    Jan 18, 2005
    Alta Loma, CA
    In your case, it's simply echo. Radio waves are waveforms, just like sound. (Light is still open to debate... wave or particle)

    So anyway, it's a waveform, and it echoes. The simplest way to visualize it is a wave on a beach. Say you have a 10 foot wave 5 miles out. That wave will be perfectly formed traveling at full speed... UNTIL that 10 foot wave is taller than the water it's in. Once it starts running out of room, it's forced up and forward, collapsing on itself. In the ocean this is the whitecap that you see. and the closer to land, the more that wave is distorted and falls forward until it is no longer anything but a distorted rush of water.

    That wireless waveform does the same thing. Once it hits that celling, it distorts just the same, and on top of that, it bounces all over the place.

    In your situation I would do this;
    First off, go wired anywhere you can. If you don't want to run ethernet, or simply can't, check out some of the new 500mbps Powerline Ethernet (HomePlug) hardware. I would limit the number of WiFi access points. Use them in combination with the HomePlug units, Even better would be if you can lower the power output of the airports. That way you can move them farther away (via homeplugs) and keep the distortion to a minimum.

    One of the very LAST things that you want to do is "extend" a wireless network, even more so in an area with a LOT of wifi signals. Think of it with the bullhorn again - Picture every AE in your house as a person with a bullhorn. Now have them all repeat everything they hear. It wont take long before all you hear is nonstop noise and you can't really make anything out.

    I hope this helps you work out your issues and feel free to hit me up with any other questions. I'm a network engineer, and I do enjoy what I do. Oh, and I do Cell networks too - mostly getting cell signals into homes that can't get coverage.
  6. ParagJain thread starter macrumors 6502

    Jul 24, 2011
    My bad, Its the other way around; Its only connecting to the airport express and not the extreme. so in a way, if I don't switch on express, it just never detects my wifi (from airport extreme).

    The wifi antenna works fine because if detects many other signals from my building..(don't have their security key ;) )

    just backed up entire thing and now taking it to service center; lets see what they can say...
  7. hfg macrumors 68040


    Dec 1, 2006
    Cedar Rapids, IA. USA
    If you look in your WiFi Network Preferences, you will probably see both devices listed with their SID. You could remove the one you don't want to connect to from the list ... or at least move the desired one to the top of the list and see if that works.

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