Do I need a stand-off of some sort to keep the center of the OCF dipole from being too close to the metal mast? Or can I just fasten a pulley through an unused hole of the top guy ring to hoist the antenna up and lower it down for service or replacement?
I think, based on reevaluating my roof and lot and trees, my plan will be to use a Rohn H30 slipped into the 5-foot tripod with 3 contact points and a roof peak cup underneath it to actually hold the weight of the mast and antenna system so that the tripod itself isn’t bearing any weight at all, only bracing the bottom section.
Then I will use synthetic rope (I’m familiar with Dyneema from vehicle winching, but may look at Dacron or Phillystran) to guy the mid and top rings in 3 directions to the best of my ability to maintain 120 degree separation and to reach sufficiently far to blocked, through-bolt anchors in the roof. In one direction I may actually use a 4x4 privacy post (or a sufficiently sturdy section of galvanized tubing or rigid conduit bracketed to it) as the base of my guy anchor if the angles work out.
IF I can’t work it out where the third guy anchorage can reach the full ~28’ before running out of roof, then I will explicitly hang the HF dipole more or less in the direction of the ~75%+ distance anchorage to ensure that the general tension is the least in that direction, on the presumption that every little bit helps. On the guy rings I’ll use a thimble if it fits through the holes or else a”quick link” and the thimble through that. All guys will be tensioned against each other till they’re all snug vs piano-wire tight and then “permanently” terminated to prevent loosening.
I’ll run my coax up the mast, securing it to the mast with zip ties at points where it won’t get hung up, pinched, or cut when lowering the mast in the future, so that it won’t just be loosely flapping in the breeze and hopefully help support some of its own weight instead of just hanging purely from the feed points. A couple loops zip tied to the base of the tripod for future service slack could come in handy.
It may be controversial to some, but I’m considering hiring a roofer to help ensure all this is done in a manner that will not compromise the roof for at least a few years, and while I’m at it I think I’ll have installed a short length of 2” PVC rigid electrical conduit with appropriate flashing bracketed to the trusses underneath with a 2” PVC weatherhead fixed on top. I’ll use that to bring the coax in, running straight down a truss to the covered patio outside the shack wall where they’ll exit the ceiling/soffit at the exterior wall and run down to the ground rod previously installed there by me for that purpose when we redid the slab. There they’ll attach to surge arrestors on a ground rod clamp before then entering back up into the same hole in the soffit and out of the interior wall of my shack immediately adjacent. Those KF7P entry panels are mighty nice and mighty tempting even if expensive, and I may go that route instead to keep things looking as nice as possible.
Going back up adds a couple more feet of coax than drilling through the brick (French entry doors, no windows), but it’s probably worth it to keep it tidy and minimize further uglifying of the back patio and raising the consternation level of the long suffering wife. And it’s certainly still shorter than the coax isn’t just resting on the roof damming up oak pollen and leaves and ball moss and tempting the squirrels with its deliciousness, before wrapping around the gutters and up along the soffit (ceiling) of the covered patio to reach the same exit point.
A 30’ mast on the roof with a 6’ GP-3 stuck on the top of it isn’t exactly stealth, but hopefully the guying and coax routing will avoid being eye-catching.
Mine was roughly 2 years ago. It looks like now, the only thing they sell is a Channel Master 15'. The Rohn used to be listed on their website, but isn't anymore.
The Channel Master Universal 20 ft. Indoor Outdoor Telescoping Mast comes with an HD television to pick up any crystal clear HD signals being broadcast in your area. It allows you to receive UHF, VHF,
www.homedepot.com
Dang, that’s what I found, too.
www.texastowers.com
www.timesmicrowave.com
