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WIFI POWER AMPS

3 posts by 3 authors in: Forums > CWNA - Enterprise Wi-Fi Admin
Last Post: July 1, 2006:
  • By (Deleted User)

    This is an email on some weighty matters, I had regarding Wifi Power AMPs and the usage of them with access points here in the US. This can make or break a WLAN and IMHO cheat a customer.

    Bottom Line Up Front (BLUF)....Why use a system that is breaking FCC rules ? Why provide only good to excellent coverage and know that future applications require more access points and capacity is another factor?

    BTW,
    I researched the vendor and WISP using the amp on the FCC website, neither could be found...???????? Perhaps it is pending certification and the use of the power amps are BETA?

    compughter's editted input:


    Devinator,

    This is how some of the major wireless WISPs are installing wireless in hospitals, hotels, schools multi-story buildings, etc.. I've seen it with my very own eyes on site surveys. That is why I am ask so many questions on Coverage V/s Capacity and V/ WLAN site surveys.

    This why we CWNPs that are trying to do the right thing are outbid on jobs and the customer is siding with the less expensive solution,

    Legacy wise this kind of client coverage scenario works.


    Some of these clients are looking to go to V/WLAN phones. The competition avoids the grid architecture with the Power Amp tactic.

    They pride themselves in shaping of the radio waves. It works very well for them too. I can't argue the engineering behind this, though I question the legality of a system with amplifiers. Your position? How do we combat this?



    VENDOR LEFT NEUTRAL


    Devinator's response:



    http://frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=47&PART=15&SECTIonfiltered=204&YEAR=2000&TYPE=TEXT

    This is the FCC rule concerning power amps.




    http://frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=47&PART=2&SECTIonfiltered=926&YEAR=2001&TYPE=TEXT




    This rule says they MUST have a grant of equipment authorization (we call this the certified system rule)




    http://www.access.gpo.gov/nara/cfr/waisidx_01/47cfr2_01.html




    This is where you can see all of the equipment authorization rules - starting at 2.925 and higher.




    If they can't show the customer a certified system certificate (see attached for an example), then they are breaking FCC rules by powering up their equipment.




    https://gullfoss2.fcc.gov/oetwl/index.html




    Here is where you can find their gear's certificate if they have one. As an example of how this works, look at the attached certificate. Then, look at the FCC Identifier (FCCID). It starts with NM5 for this particular company. If you type NM5 into the Grantee Code, you'll see everything that vendor has certified. :-)

  • Good post Reg,

    One thing I'd like to say here is that if vendors are throwing out all kinds of weird solutions whereby AMPS are used and this is causing you a problem because you're competing with them, then I would ALWAYS mention to the customer to VERIFY that the other company is using an FCC approved system. Of course the customer will not know how to do this verification, so you have to show them. You should have the customer ask the vendor for a copy of their Grant of Equipment Authorization (from the FCC) or the number of the Grant (called the FCC ID). They can plug the FCC ID into that search engine to verify that the system is authorized by the FCC. If it's not, then they can get themselves into a mess by buying and installing the system.

    If your competitor is breaking the rules in order to offer something more competitive, I would simply point this out to the customer as part of competing for their business. :-)

    Devinator

  • I have compiled what I call my "Bad Install" folder, where I take pictures of bad wireless installations. Two of them (I only have pictures of one) have been where there was an amplifier installed with out any regard for power limits. For example:

    1W Amplifier with a 19dBi directional antenna (80 Watts not taking into account the 18" LMR 195 cable), and this was in a hotel. I informed the owner, but he seemed like it didn't matter because the system was working.

    One question I had was this: In many buildings you see "Warning, microwave oven in use". I think that this is for people with pacemakers. What I am pretty sure of is that a microwave oven doesn't leak 80 Watts (or anywhere close). So, should I put up a sign "Warning, high powered microwave communications in operation."? Is this actually a health hazard to pacemaker wearers?

    I of course wanted to install the system correctly so that high powered system wasn't in use, but I don't really have much of a leg to stand on because realistically, the FCC isn't going to show up at the front door of the hotel. However, if there is a real health hazard then maybe I have a legitimate reason to offer my business solution.

    Thanks a lot for the thread because I have had thoughts of this nature as well.

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