Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site brl-tgr.ARPA Path: utzoo!linus!philabs!cmcl2!seismo!brl-tgr!tgr!Karz.Wbst@Xerox.ARPA From: Karz.Wbst@Xerox.ARPA Newsgroups: net.ham-radio Subject: Re: Roof Mounting a Beam Antenna Message-ID: <482@brl-tgr.ARPA> Date: Tue, 6-Aug-85 18:51:08 EDT Article-I.D.: brl-tgr.482 Posted: Tue Aug 6 18:51:08 1985 Date-Received: Sun, 11-Aug-85 00:15:17 EDT Sender: news@brl-tgr.ARPA Lines: 34 Bruce, I have a roof mount for my Hygain Explorer 14 that I'm quite pleased with. My antenna mast is mounted on the back side of the roof a few feet from the peak. I built a "frame" for the mast mount out of 3 pressure treated 2X4s about 25" long that lie across the joyces and are bolted to the joyces with lag bolts. The 2X4s are parallel to each other and spaced about a foot apart. They are not quite parallel to the roof line and are caulked on their "uphill" sides so that they won't dam up rain water. The frame serves to distribute the load of the antenna across the joyces. I purchased 2 2' lengths of fireplace lentil at a local brickyard. The lentil has an "L" shaped cross section. I drilled holes in the lentils and mounted them on the "frame" parallel to the fall line of the roof (that is, almost perpendicular to the 2X4s) and with the "feet" of the "L"s pointing outward. I spaced the lentils the mast diameter apart. I then drilled a hole through the mast about an inch above the bottom and corresponding holes in the lentils. The mast pivots on a 1/2" bolt through one lentil, the mast, and the second lentil. The antenna is held up by aircraft cable guys anchored to the roof with lag bolts. The mast is 12' high. I used roofing cement around all lag bolt holes and have had no problem with leaks. The antenna has been up 2 years this month, and I've had no problems whatever, but I do make a point of checking the installation twice a year since the failure of any one lag bolt will bring the system down. Except for the driven element, the system is a "plumbers delight" (just one big short), so I feel that the #4 copper ground wire from the mast gives pretty good lightning protection. Nevertheless, I keep the feedline disconnected from the rig and grounded when not in use as an added precaution. I hope my experiences is of some help to you. Bob Karz K2OID