|
Rigid, unguyed dipole end supports?
"Bert Hyman" wrote in message . .. The size and layout of our city lot means that I can fit a 40 meter dipole in the back yard with one end supported at the peak of the roof, but with no way to guy a mast to hold up the other end. Power lines run directly along the property line in back, there electrical service line runs right across the roof of the detached garage and there are no trees back there. I picked up a couple of [cheap] 10' steel mast sections at the local Radio Shack and attached the lower section to our fence with conduit clamps, but just the weight of the antenna under minimum tension causes the upper section to bow significantly. I'd like to replace the far-end support with something that will stay erect under tension without guys. Getting higher than 20' would be nice too. Can anybody offer practical suggestions to someone with essentially no mechanical skills, pointers to articles on the subject or commercial products? -- Bert Hyman W0RSB St. Paul, MN While it may not be too inexpensive, you can use some Rohn 25G tower sections. There may be soe other inexpensive tower sections you can use. I was in a similar situation. I could support one end and the middle of an 80 meter dipole. I found some used tower for about $ 30 per 10 foot section. I was going to save it to put up a tower someday. I decided I could put two sectons together and also use one of the 10 foot sections of TV mast like you have. I think the TV mast woud fit over one of the legs. I also put a big eye bolt at the top of the mast with a rope through it so I could pull up the antenna wire. This was done before the tower was raised so there is no need to climb it. To climb it I would think you would want about a yard of cement in the ground, then you could go up to about 30 feet of tower. I just rested the tower on the ground and took a couple of radiator clamps and fastened it to the pipe that held up the corner of the chain link fence. I used it this was for about 3 years before I moved. |
Rigid, unguyed dipole end supports?
|
Rigid, unguyed dipole end supports?
On Mon, 06 Dec 2010 14:23:46 +0000, Bert Hyman wrote:
The size and layout of our city lot means that I can fit a 40 meter dipole in the back yard with one end supported at the peak of the roof, but with no way to guy a mast to hold up the other end. Power lines run directly along the property line in back, there electrical service line runs right across the roof of the detached garage and there are no trees back there. I picked up a couple of [cheap] 10' steel mast sections at the local Radio Shack and attached the lower section to our fence with conduit clamps, but just the weight of the antenna under minimum tension causes the upper section to bow significantly. I'd like to replace the far-end support with something that will stay erect under tension without guys. Getting higher than 20' would be nice too. Can anybody offer practical suggestions to someone with essentially no mechanical skills, pointers to articles on the subject or commercial products? I set up an 80m dipole using three masts made of 20 foot long 2x4's from the lumberyard. I don't use any guy ropes, even on the end masts. I just made diagonal braces from shorter 2x4's -- about 6-8 feet each -- with two braces on each vertical mast. The braces are attached to the mast with carriage bolts and one long lag screw for the brace that attaches to the narrow edge of the mast. The braces are arranged at 90 degree angles to each other and are dug into the ground about 1 to 2 feet deep (that's all I can dig in this yard before hitting hardpan). Each brace has a short "deadman" stick screwed on the bottom of it to keep it from pulling out of the dirt. There is also a vertical brace dug into the dirt and rising about 3 feet above ground line. The actual mast is lapped onto the vertical brace with two carriage bolts. The purpose of the vertical brace is mostly to get the maximum rise out of the 20 foot mast. You could also just bury the end of the mast itself into the dirt. It's been up for a year now and hasn't come down even in the wind storms and ice storms we have had. Be sure and orient the 2x4 mast so the "strong" direction is opposed to the weight of the antenna. |
Rigid, unguyed dipole end supports?
In J. Todd
wrote: In article , says... Can anybody offer practical suggestions to someone with essentially no mechanical skills, pointers to articles on the subject or commercial products? Maybe a strut halfway up the fence side of the mast, with a stay from the mast top, over the strut end, and secured to the bottom of the mast. Tension to straighten the bend, Think sailboat "diamond stays" That sounds like something I've seen on utility poles, except that the guy doesn't connect at the bottom of the mast, but goes straight down from the strut, parallel to the mast, and is anchored in the ground. I probably have enough room on the other side of the fence for something like that. BTW, I'm collecting and "analyzing" all these responses for next spring; the ground's already frozen and we have our first foot of snow cover for the winter. -- Bert Hyman W0RSB St. Paul, MN |
Rigid, unguyed dipole end supports?
On 12/6/2010 9:23 AM, Bert Hyman wrote:
The size and layout of our city lot means that I can fit a 40 meter dipole in the back yard with one end supported at the peak of the roof, but with no way to guy a mast to hold up the other end. Power lines run directly along the property line in back, there electrical service line runs right across the roof of the detached garage and there are no trees back there. I picked up a couple of [cheap] 10' steel mast sections at the local Radio Shack and attached the lower section to our fence with conduit clamps, but just the weight of the antenna under minimum tension causes the upper section to bow significantly. I'd like to replace the far-end support with something that will stay erect under tension without guys. Getting higher than 20' would be nice too. Can anybody offer practical suggestions to someone with essentially no mechanical skills, pointers to articles on the subject or commercial products? Hi Bert: Let me tell you what I'm using for my dipole. I have a 40' tower about the middle of my lot. The dipole center is supported by the tower and the ends are supported by flagpoles. In the front yard its a real one piece spun aluminum flag pole for the "looks" and in the back the pole is a 21'long 1 5/8" steel pipe that is used for the top rail in industrial chain link fencing. Both poles are mounted as flagpoles are commonly done (look up erecting flagpoles on the web) with 2' of the pipe in the ground making it 19' out of the ground. The advantage of flagpole mounting is it's relatively easy to take down if maintenance is need. My dipole is heavy as it's a HB fan dipole and covers 160 through 30 meters. I though the pipe would bend too much so when I put it up I fastened a rope the back side of the top for a back guy. I never used it and when the time comes to work on it (paint maybe) I will remove it. Works well and looks good and not hard to put up as I did it with out any help. John W3JXP |
Rigid, unguyed dipole end supports?
In John Passaneau
wrote: In the front yard its a real one piece spun aluminum flag pole for the "looks" and in the back the pole is a 21'long 1 5/8" steel pipe that is used for the top rail in industrial chain link fencing. The fence top rail stuff is actually rigid enough to not only stand up by itself, but to support a little side load? Any idea how much farther up you could have gone without the thing starting to get floppy? Sounds like something worth looking at. -- Bert Hyman W0RSB St. Paul, MN |
| All times are GMT +1. The time now is 09:38 AM. |
Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
RadioBanter.com