Ron, I apologize for addressing my response to Paul instead of to you.
The installation of any metal other than bronze or stainless steel in a salt-rich environment is always problematic. I am using two DB-224 dipole antennas at some inland sites, and they are weathering quite well. However, I have some commercial UHF repeaters on Cypress Ridge in California, just about 3/4 mile from the Pacific Ocean and about 700 feet AMSL. I've had to replace a lot of carbon steel hardware with corrosion-resistant items at that site, but the DB-404 and DB-408 dipole antennas seem to be holding up fairly well- at least, to my expectations. I don't expect any antennas to last for 20 years at this location, so I replace them at four years. Perhaps I should mention that these antennas are on 16-foot masts, and are fairly easy to inspect or replace. One of my DB-408 antennas has been struck by lightning at least three times, but the repeater it serves has never gone off the air. I know when a strike has occurred because I have a sharp-pointed terminal on the top of the antenna, and it gets melted into a ball when a strike occurs. I attribute this 100% survival record to a very robust grounding and bonding system. I assume that your antenna is on the WXTB tower at Holiday, FL. Is it side-mounted below the top, so that it won't likely take a lightning hit? 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright Sent: Saturday, September 01, 2007 9:29 AM To: [email protected] Subject: Re: [Repeater-Builder] DB224 Survival in Florida Eric, We have pretty much determined the feedline is ok since the VHF is shared with a UHF system and the UHF is fine. It still could be the crossband coupler at the top. However, we have seen a number of exposed dipole antennas eaten with the salt air, many in 5-6 years. Mostly ones less than 1 mile from the water. Salt air studies show at about 1 mile from a salt water the salt in the air starts to drops dramitically. Although we are in the lightning capital of the US, 3rd in the world, few side mounted fiber glass enclosed antennas have problems and do last much longer in the salt air. Also fiber glass enclosed antennas in some installs at 300 ft and top mounted have been up for about 20 years. I have heard of the station masters having problems due to the solder assembly, but I've seen many last 20+ years probably because most are side mounted and do not suffer direct or server lightning. It will be a long time before I install another exposed dipole antenna this close to the salt water. Just seen too many problems. 73, ron, n9ee/r >From: Eric Lemmon <[EMAIL PROTECTED] <mailto:wb6fly%40verizon.net> > >Date: 2007/09/01 Sat AM 09:44:52 CDT >To: [email protected] <mailto:Repeater-Builder%40yahoogroups.com> >Subject: [Repeater-Builder] DB224 Survival in Florida > >Paul, > >Eleven years in a salt-air and lightning-prone environment is pretty darn >good! I daresay the Super Stationmaster would not last that long. >Fiberglass vertical antennas can be permanently damaged when struck by >lightning, whereas the aluminum dipoles might shrug off such abuse. At >least, that's been the experience at nearby Vandenberg AFB. > >It is not clear from your post if you have established beyond any doubt that >it is the antenna causing your SWR problem. Have you determined that the >feedline is not cracked or dented due to flexing, not worn through at some >point, no water in the line, center pin(s) haven't pulled out due to >elongation, no bullet holes, etc., etc.? > >73, Eric Lemmon WB6FLY > > >-----Original Message----- >From: [email protected] <mailto:Repeater-Builder%40yahoogroups.com> >[mailto:[email protected] <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of Ron Wright >Sent: Saturday, September 01, 2007 7:12 AM >To: [email protected] <mailto:Repeater-Builder%40yahoogroups.com> >Subject: Re: RE: [Repeater-Builder] Wal Mart effect makes it to the >Communications Hard (feed)-Line industry > >Paul, > >I have a DB224 at 1175 ft above ground 1/2 mile from the Gulf of Mexico here >in FL. Put up in 1996 and it is having serious problems, 2:1 SWR on the >ground. Think it is the salt air. The connections, on antenna and >connectors, were coated and sealed before install. Other services with >exposed dipoles have had the same problem here. > >We have same antennas about 5 miles from the Gulf that last for years >although none past 20 years. Have seen about 5 of these replaced recently, >most VHF. > >When I replace my DB224 I am going to a SuperStation Master fiber glass >pole. It is obvious the exposed dipoles have a survival problem in this salt >air. > >I know what you mean about the fiber poles and lightning due to the >soldering connections. If top mounted would be reluctant, but have seen >these last over 20 years and still had plenty of life in them in some harsh >enviorments. > >I like the DB224 with it squeeing of the pattern, but exposed dipoles can >have problems. Same with towers up north with ice falling off a tower. > >73, ron, n9ee/r > ><unrelated text deleted> > > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
