[colanderman]

Yep. Specifically you'd need to adjust your TX power down to 27 dBm (from a max of 30 dBm) for an AP, or 29 dBm for a station. http://www.air802.com/fcc-rules-and-regulations.html gives a nice summary.

Basically APs on 2.4 GHz are only allowed 36 dBm (4 W) EIRP, no matter what antenna shape. This is usually not a problem though, since stations tend to have weaker transmitters anyway, but will still benefit from the AP's enhanced antenna gain.

[Spare_account]

OK, so if by the time the signal exits my property it has dropped below mandated limits, there is no harm done right?

If I aim my antenna such that I contain the illegal power region within my property, will there be an unintended consequence?

To be clear, I'm referring to a house not an apartment so I don't have any concerns about upstairs or downstairs neighbours.

[hydrogen18]

No, that is incorrect.

The domain of the FCC extends to all property of the United States of America, be it public or private.

[colanderman]

The reason this is important is that it prevents private corporations from interfering with public air space (as discussed previously on HN [1]), and prevents landlords from interfering with the rights of tenants to legally place outdoor antennas (such as satellite dishes).

[1] https://news.ycombinator.com/item?id=8406022

[colanderman]

RF energy doesn't quite work like this. If your transmitter has a high EIRP (either due to antenna directionality or high TX power), then its signal is going to travel a long way, even after the signal level has dropped to that of a lower-EIRP transmitter. That is simply the inverse square law at work.

You could place sufficiently absorptive materials that this isn't so (e.g. enclose your house in a Faraday cage). But as hydrogen18 points out you're still limited by the FCC.

[ocdtrekkie]

I think FCC laws technically apply within your property as well. Hypothetically, what happens if your non-compliant device blocks a visitor on your property from calling 911?

[sjwright]

I think this falls under the pragmatic category of "you're only breaking the law if you get caught."

[ocdtrekkie]

Oh of course, and there's actually a surprising number of FCC rules you'll never get caught breaking. GMRS license violation is another.

[tropo]

He's not operating under FCC part 15. He's using FCC part 97 instead, with the appropriate license.

His rules: 1500 watts PEP, unlimited EIRP, channels 1 to 6 only, no encryption

That's better than a normal microwave oven.