Also, when a Part 15 station uses a dish, all that ERP only affects you when the dish is pointed directly at you...for the most part....and those beamwidths are very narrow for a 24 dBi dish.
73, John - K8OCL
From: "John B. Stephensen" [email protected] To: "Nate Duehr" [email protected], "Tony Stone" [email protected] CC: [email protected] Subject: [amsat-bb] Re: Fw: Re: More Clutter on 2.4 GHz Date: Mon, 9 Oct 2006 22:56:01 -0000
If you're staying above the satellite segment then you're not creating problems for amateur satellite users. The long-term problem is that non-hams won't care as much, especially as usage increases, and 47CFR97.303(j)(2)(ii) says that we must accept interference from all other users so we can't force them to change frequencies. Interestingly, there is no statement that hams can't cause interference to unlicensed devices.
73,
John KD6OZH
----- Original Message ----- From: "Nate Duehr" [email protected] To: "Tony Stone" [email protected] Cc: [email protected] Sent: Monday, October 09, 2006 21:45 UTC Subject: [amsat-bb] Re: Fw: Re: More Clutter on 2.4 GHz
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 W4TAS
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 certifications.
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 _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite
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Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb