Bob,

You are NEVER going to hear your neighbor's WiFi @ 10 miles! Come on, Bob!

I have experienced this near / far phenomenon of which you write many times It is something in the RF environment with which we need to learn to deal. I work in a location where I normally monitor 40 -60 WiFi devices at the same time, yet I manage to get a signal through such nasty terrain. A hand-full of neighbors wouldn't make me completely re-design an OSCAR and drop an entire transponder!

You must be one of those pessimist we were writing about earlier. Put the math aside and go out to your front yard and meet those fine WiFi folks! (HI)

Vy 73, John Champa - K8OCL Former Executive VP - AMSAT

From: "Robert Bruninga" bruninga@usna.edu Reply-To: bruninga@usna.edu To: AMSAT-BB@amsat.org Subject: [amsat-bb] Re: S band interference solution Date: Thu, 5 Oct 2006 15:28:09 -0400

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These are 100 mW devices...maximum! That means they have to be relatively close to your QTH for you to hear them.

Two big words there. "Relateively" and "close"...

The laws of physics trumps all opinions...

All of these give the SAME power at your antenna:

• A 100mW device at 1 mile
• A 10 W device at 10 miles
• a 1000W device at 100 miles.

Or this one:

• A 100 mW device at 10 miles
• A 10 Watt device at 100 miles
• A 1000W device at 1000 miles LEO
• A 400 Kw device at 20,000 miles GEO orbit

Now our birds do not have 400 Kw to downlink at S-band to overcome Your neighbor's WIFI at 10 miles away.

Even if you throw away 30 dB of antenna gain (the neighbor will not be in you main lobe, this then makes the 400W Satellite coming in your MAIN beam no stronger than a neighbor at 10 miles away with a 100mw device coming in the back of your dish.

Yes, it is only 100 mW, but when it is 20,000 times closer, it is 400,000,000 times stronger.

De WB4APR, Bob

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