Ken & Co I'd like to put my hat in the ring here..
Back in the 90's a Diamond 23A 2M antenna was at 5000' for 10 years before it was replaced. It stood off the SE corner of a 300 meter national transmitter tower at about the 30M section, and serviced a vast area of country. The tower was on top of the coastal range in North Queensland. The prevailing SE weather was a constant worry for the tower repair crew, and often salt crystal could be found in dry weather. When the antenna was removed from the site, it was very evident that one side of the radome was more opaque than the other, which was put down to the SE weather. The gland "O" rings had completely broken down into black powder, and about 5 ounces of water was drained from the radome. It went back into service on a packet BBS at sea level for many years there- after, having been recoated and a hole in the base to drain any condensation. If I recall correctly, the collinear solder joints were silver soldered before it was delivered to the tower crew. John Ken Arck wrote: > At 06:28 PM 3/13/2008, Paul Plack wrote: > >> Cort, >> >> >> (1) Can be addressed by using antennas with one-piece radomes. In >> theory, the right preparation to seal junctions might also work. In >> long-term installations, the gel-coat on the radomes will break down >> under UV radiation from the sun, followed by the fiberglass, which may >> allow water migration through the radome. > > > <-----I've always done this (wrap the joints first with the sealing > goop, then electrical tape over that and finally a tie wrap at the outer > end of the tape to prevent it from unravelling with time) and have never > had water penetration. Not once. > >> >> (2) Broken internal connections can develop quickly if a fiberglass >> radome antenna is top-mounted on a tower. If it's side-mounted, with a >> brace for the top to stop waving in the wind, they can last much longer. > > <---Yep, Support the top with something non-conductive to keep the > antenna from swingin' in the breeze goes a long way at increasing > longevity (my oldest Diamond still in repeater service is almost 10 > years old). > > > Ken
