A1. Sure, why not? For bridge shots that I setup, most of the time I use a NPRM, or a non-penetrating roof mount. It's pretty much a mast that has supports and allows you to use patio stones or blocks to keep it held down. You could use one of those and then attach a metal rack to the mast horizontally to allow both antennas to mount to the rack. Well, I tend to get a little creative when I set stuff up; there may actually be a kit for dual antennas...
A2. Yes, there sure are. I have some 1310's with the external antenna option going from a N-TYPE cable outside and then converted to RP-TNC inside. I believe I got the required converters from a place called Fab-Corp...
A3. As for the maximum gain, I think that falls into a potential FCC maximum transmit power situation. You may want to watch out for this, but I'd imagine that any standard n-type Antenna ,short of the very high gain ones, would work out fine. Just don't go overkill with it and you shouldn't have any problems. If the run is short then you probably don't need anything over 10Dbi...
A4. I would recommend that you use 5Ghz for the test. It has more open channels. The only potential issue I see with using 802.11N bridging is that if everyone starts putting up N bridges you could potentially get interference from two devices transmitting on the same channel(s). Now, it's probably not likely can you can effectively dominate the radio waves. You may want to get a copy of airmagnet to see what signals in 5Ghz are out there to exclude them from your channel list. Although I haven't dealt with N yet, I'd imagine interference is still interference...
Anyone else play with the 1252 in bridge mode with 802.11N enabled?
