The reflector in the photo looks like it has been hoisted by clipping the halyard to a hole in one of the "plates" and running it up to the spreader. This is NOT the "catch rain" setup that Gene and knowledgeable others call for. In order to work BEST, the interlocking plate type reflector needs to be set up so that one of the "pockets" points up, and so would "catch rain" if it were raining. Double "catch rain" is even better. Tests run by West Marine in 1995 and separate ones done by in 2007 by the Marine Accident Investigation Branch in England bear this out. These tests also showed that the mounting angles of "enclosed reflector" types was not as important. Essentially because the enclosed reflectors had such narrow angles of reflectivity they wouldn't work well in actual use, regardless of how they were set up. The interlocking plate reflector - even mounted incorrectly - worked better than the enclosed type.
http://offshore.ussailing.org/SAS/General_Information/Safety_Studies/2007_Radar_Reflector_Study.

http://www.ussailing.org/safety/Studies/radar_reflector_test.htm

I laugh each time I see one of those expensive enclosed reflectors.