Power Levels

[mjpearson]

We have an older wireless radio system (pre 802.11). The radiso have transmitting power of 15 milliwatts. While doing some research on 802.11, I've found that most systems have an upper limit of 15 milliwatts. I presume 15 is the regulatory limit for power?

I've seen advertisements for amplifiers that approach 100 milliwatts and above. Would I need to obtain a license to use the amplifiers above 15 milliwatts? Are these amplifiers legal without a license?



Mike

 

[iownroot]

802.11 NICs operate between 1 and 200 milliwats. Where did you decipher the 15 milliwatt upper limit?

Licensing is usually required based on frequency. 802.11. 802.11b, and 802.11g, use the 2.4Ghz ISM band, and 802.11a uses the 5Ghz UNII band. Those are the public use bands. Frequencies outside these require FCC licensing.

CISSP, MCT, MCSE2K/2K3, MCSA, CEH, Security+, Network+, CTT+, A+

 

[mjpearson]

Thanks,

>>Where did you decipher the 15 milliwatt upper limit?

* My existing radio system specs say it has an xmitter power of 15 milliwatt.

* I was looking at some devices from Trendnet and the specs say that the xmitter is 15 milliwatt.

* I was looking at some devices from D-link and they too say they're using 15 milliwatt.

Everywhere I looked the 15 milliwatt specification kept showing up so I presumed that this must have been some sort of regulatory limit.

Various devices on my existing radio system are starting to fail so I opened up one of the devices and found a 802.11b PCMCIA card. They are attached to roof mounted antennas. I have a relatively small campus and I'm getting reasonable results. The devices are used solely for bridging.

The exiting devices are no longer manufactured so I figure I need to start over. Since I have to get new devices, I figure I should bump up to 802.11g.

Given that my old devices worked well with 15 milliwatt and I'm on a tight budget, I'd continue to use 15 milliwatt devices however, if doesn't work, I'm thinking that I might be able to use an amplifier for the distant sites. Thus I started to get concerned that I'd need a license.

Any recommendations?


mike

 

[wybnormal]

15mw is pretty low. The newest long range cards are 200mw. The typical Cisco 350 AP is 100mw but the older 340 APs are 30mw. The average consumer card is around 30mw of output. The Linksys is 30mw but the Alchemy hack gives you from 0 to 100mw.

MikeS

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