[amsat-bb] Re: Fw: Re: More Clutter on 2.4 GHz

Nate Duehr nate at natetech.com
Mon Oct 9 14:45:42 PDT 2006

Tony Stone wrote:
> The part 15 rules for 2.4 GHz operation state that a maximum transmitter
> output of 1 watt with a 6 dbi omni antenna is legal. This is 4 watts eirp.
> With a directional antenna you must decrease your transmitter power
> 1 db below 1 watt for every 3 db antenna gain over 6 dbi.
> Confusing as this may seem, it means that you can have 250 milliwatts
> of transmitter output with a 24 dbi gain antenna. That is 18 db over
> the original 6 dbi which is 6 units of 3 db each. This means that the
> transmitter power must be reduced from 1 watt to 250 milliwatts (6db).
> This is an effective isotropic radiated power of 64 watts and is perfictly
> legal.
> Check the gain of a 36 inch dish at 2.4 GHz and do the calculations to
> see if it is legal or not.
> 73
> Tony

Tony -

Sorry if I got it wrong.  I was going off of some of Cisco's 
certification documentation for certifying their Access Points, perhaps 
they're being overly conservative on their numbers to assure 

I couldn't find my old link to the REAL rules so I might have been a bit 
overzealous in my numbers on the low side.

Still: In reality it's a free-for-all... you could blast just about 
whatever you want point-to-point with gain antennas and there'd be 
little way to find that you were doing it, and even less desire to do 
anything about it.

Sorry to the list -- mostly the only reason it relates to anything 
Satellite-related is the general noise level on 2.4 GHz, and I'm 
creating more "noise" on the list than that... (GRIN).

Happy to take this offline if someone wants to continue.

Nate WY0X

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