>My home router has three bands, one for "Guests". I can use the other two and not have problems with my guests.

In this country BT (British Telecom) which is one of the main broadband providers incorporates something similar into their routers.
There's a 'main' channel which is reserved for 'internal' use an a second (with limited bandwidth) which allows 'guests'
If you choose to make the 'guest' channel available anyone can park outside your property and use that for temporary broadband access.
But I say 'everyone' in a limited sense - only those who are also on BT and have made *their* guest channel public can use it.
I make mine public because I'm in such a remote spot that it never gets used.
In return I get access to thousands of free Wifi hotspots. :-}

>Also, external antennas are better than internal, giving stronger signals. I've heard really good stuff from people I know about this one. http://www.amazon.com/dp/B00YY3XSSA/ref=wl_it_dp_o_pd_nS_ttl?_encoding=UTF8&colid=R7MN2XOU4UIX&coliid=I1M87WTCN49TXR&psc=1


I'll take a closer look at that. At the moment I need some way of reliably sending CCTV over about 100yds. None of my current Wifi stuff seems capable :-{