mast mount
While Murray makes some good points, one thing to consider is WHEN you are likely to use radar. I'm guessing that 90 of my radar time is when I'm motoring, or at least motorsailing. It's either night (no wind) or I'm in deep fog (no wind.) I have an 18 inch radome mounted approximately one meter above the lower spreaders, and the 110% jib never touches it. Being fraction rigged, I never use a genoa, so a mast mount made the most sense for me. Additionally, I like the fact that all those microwaves are farther overhead with a mast mount than they would be with a pole mount. (Technically, btw, those "poles" are more properly called "radar masts" so you're going to end up with mast mounting no matter which option you choose. The real question is whether you want to erect an additional mast. On a sailboat, the pole is the thing the foredeck guy wrestles with while everyone else drinks beer on the downwind leg.)