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New Member


What kind of amplifier is recommended for AP 1200?

Please help


Khurshid Khan

Cisco Employee

Re: amplifier


Please be aware that Cisco does not support the use of amplifiers with any of the Aironet product range and if you do use one then it is the resposibilty of the installer to ensure it complies and is certified to all local laws, as the system has been moddified and as such the certification of the product done by Cisco is no longer valid. There are customers out there who use amplifiers, but they undertake their own certification with the local authorities

New Member

Re: amplifier

I understand Cisco's point of view and stance on amplifiers. But in the event that a amplifier is used, does anyone know the formula to use to see if the total antenna gain is exceeding FCC or local laws. Specifically when testing the connectivity between two BR350's with 13.5dBm antenna's with maximum transmit power of 100mw I only see about 37% signal strength between the two devices. However, if a 1watt amplifier is installed the signal strength increases to above 50%. I am concerned that I may be surpassing the maximum output power specified by the FCC. Any ideas on how to tell?

New Member

Re: amplifier

The FCC has put out a statement that it is illeagle to use any amplifier with 802.11 products unless the amplifier and the system have passed the FCC testing as a unit. This is why Linksys can sell an amplifier, and others like Wave Wireless can sell one. But most of the amplifiers being sold are by independant companies who do not make access points. These companies usually say the product must be used in accordance with the law. It is up to you to know the laws, and apply them properly.

The FCC also came out with a statement that says that an installer can no longer certify that a 802.11 system complies with the part 15 rules. The entire system bust be previously tested by the manufacturer and approved by the FCC. If you use an amplifier, you are in violation of the rules and may face stiff penaltiies from the FCC.

Be also aware that there are licensed users of this spectrum. Your manual clearly states that you may not cause interference to them. In Dallas, the FCC shut down an apartment complex WLAN because it interfered with the licensed users.

You should design the system to work without the amplifiers. With the proper antennas, you should never need them. This also reduces this unwanted interference.

The answer to your technical question is to do all the calculations in dB and just add or subtract the numbers. For example AP @ 100mw = 20dB, antenna gain 3dB, coax loss -3dB total 20dB.

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