I did that once and thought the bends in the pipe looked ugly. I wanted a simple vertical mast. The simple mast is also stronger because I can use "U" bolts to secure it to a rafter and a floor joist that are about four feet apart. Results in the very strong installation. It is build exactly like a plumbing vent, just a long pipe with the last few feet above the roof. The coax run is completely 100% out of the weather.
On Sun, Jun 10, 2012 at 7:06 PM, DaveH <[email protected]> wrote: > > > The easy way to mount the antenna: > > > > Head over to Home Depot and get a 1" Tee, a 1" flange, a 1" > > nipple, a 12" to 18" 1" pipe, and a 6" long 1" pipe. > > > > The antenna goes on top of the 18" pipe. That screws into the > > tee. The bottom of the Tee gets the 6" pipe. Coax runs > > straight through the 18" and 6" pipe. Nipple goes to the > > flange and the tee. Flange mounts to the house. If you need > > to get a bit further out, change out the nipple for a piece of pipe. > > > > Spray paint it all black ( or what ever) and move on. > > > > Bob > > > > On Jun 10, 2012, at 7:43 PM, Jim Lux wrote: > > > > > On 6/10/12 4:24 PM, Chris Albertson wrote: > > >> On Sun, Jun 10, 2012 at 2:50 PM,<[email protected]> wrote: > > >> > > >>> ... 3m > > >>> of antenna cable is no problem. Antenna position is more > > important than > > >>> the exact type of antenna. I'd rather have a decent > > antenna at a very good > > >>> site, than a very good antenna at a slightly worse antenna site > > >> > > >> > > >> > > >> 3M is trivial. 30M will work fine too. > > >> > > >> I agree about the location really mattering more than > > anything else. What > > >> I did was drill a 2" hole through the roof up from the > > attic and push a 10 > > >> foot gallanvised iron plumbing pipe up. > > > > > > you would probably want appropriate flashing around that to > > prevent water (and vermin) ingress. > > > > > > > > > The antenna sits on thop ithe > > >> pipe and is higher then the roof top ridge and then the > > cable go down the > > >> center of the pipe. I pipe flange on top of the pipe > > makes a perfect > > >> mounting platform. I used a timing antenna comes inside > > a white pointed > > >> plastic radome. These sell for just under $30 on eBay. > > Maybe it is > > >> coincidence or not but the four holes pin the standard > > pipe flange match up > > >> with the four holes in the bottom of my antenna and there > > is enough room > > >> inside the hole in the center for an "N" connector. It > > is worth getting > > >> the antenna "done right" because it is the most important > > part of the > > >> entire system. Those dome type antenna are worth it. > > the shape is > > >> designed to shed both bird poop, and snow. Birds can be > > an issue with a > > >> flat top antenna, no snow here. > > > > > > You probably get snow every few decades (it snowed in > > Malibu a couple years ago, for instance), but I wouldn't > > worry about snow loads, even so. <grin> > > > > > > > > > HOWEVER, your scheme is going to be tricky to pass muster > > with the National Electrical Code. Two aspects need attention: > > > You need to have a ground wire from the mast to the ground point > > > and > > > You need to have some form of ground of the coax shield at > > the point where the coax enters the building. (a "listed > > antenna discharge unit" is the usual way). > > > > > > > > > While Southern California isn't exactly the lightning > > capital of the world, we do get some. A bigger concern (and > > the primary reason for the code requirement) is that above > > ground power lines can come down and touch your antenna. > > > > > > And someone living in a more lightning prone area is going > > to want to take those precautions. > > > > > > The installations I've seen typically use the same general > > "pipe" scheme (using rigid conduit, which looks a lot like > > pipe, but has a smooth inside with no burrs) to a box on the > > roof, and then regular conduit running down the outside of > > the building. Then at the point of entrance, the ground > > bonding conductor goes from the conduit to ground, and > > there's a coax grounding block in a box at the place where > > the hole in the wall is. > > > > > > > > > Granted, if lightning does hit, everything connected to the > > antenna is going to fry, unless you have some sort of > > reradiation scheme to provide an air gap. That's what we do > > when we test GPS receivers destined for space, where you > > don't want to take the risk of killing the expensive flight hardware. > > > > > > > > > _______________________________________________ > > > time-nuts mailing list -- [email protected] > > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > and follow the instructions there. > > > > > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Chris Albertson Redondo Beach, California _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
