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Author Topic: 1 Acre lot but no trees  (Read 5146 times)
VO1GXG
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Posts: 60




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« on: June 01, 2007, 05:39:53 AM »

My house is located on a acrea lot , i can have full use of the back yard for antennas ( parents said i can Tongue ) SO what can i do to put up a dipole ? i have no trees in my back yard . I was thinking if i can get a used exstension lader i can use it as a tower of sorts . Any suggestions on what i can do ?
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N3OX
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« Reply #1 on: June 01, 2007, 07:01:40 AM »

I don't know what your budget is but I like these a lot:

https://shop.dx-is.com/categoryNavigationDocument.hg?categoryId=5

The 40 foot one will support a light wire dipole right at the tip... maybe not through fierce storms, but it can come down easily.

A guyed extension ladder is often used but maybe looks a little funny ;-)  It'd work in a pinch though.

There are a bunch of antenna masts that you can make out of lumber... the ARRL antenna book has a few... later I can look online or maybe someone can supply a link.

Vertical antennas are also an option... then you don't have to worry about masts at all.  If you're overlooking the water there (you look like you're close to it as a town) a vertical will do very well for DX signals in the direction of the water.  

73,
Dan

 
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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
N3BIF
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Posts: 1190




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« Reply #2 on: June 01, 2007, 07:29:22 AM »

 Attach an inverted v to the highest point of the house. Only one support needed . Attach the ends to stakes in the yard, insulated safely and affording protection to passersby of all ilks.  
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WB2WIK
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« Reply #3 on: June 01, 2007, 09:03:46 AM »

Unless you have a very tall house, attaching an inverted vee to the highest point on the house may not work well.  An 80m inverted vee, for example, should be up about 65' above ground at its apex and each end should be at least 10' above ground, else it will work quite poorly and have a lot of earth-induced end-effects.

You could, of course, add a 20'-30' mast to the house and then use the top of that mast as the high point on an inverted vee.  If you do something like this, always install a pulley at the top of the mast, with a rope over the pulley, to raise and lower the antenna -- otherwise, any time you want to make an adjustment it will be a huge pain in the butt.

WB2WIK/6
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NA0AA
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« Reply #4 on: June 03, 2007, 11:44:00 AM »

If you can manage 33' of vertical, you have a 40 meter vertical which can be tuned for other bands.

You don't really have to get up that high - if you bury a couple of 4x4x12 posts 3' deep, then add 10' of chain link fence top rail pipe to it, you are a good 17' in the air - more than enough for the ends of an inverted V - my 20 meter dipole is scarcely high than that and it works just fine.

Ladders would be fine if you get 'em cheap enough but for permanent installation IMHO they look too funky, YMMV.

A variety of push-up masts can be used to good effect as well if you don't have a problem using guy wires.

For ideas, try Texas Towers, they carry many different items that may give you some thoughts.

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KG6OMK
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« Reply #5 on: June 03, 2007, 04:33:16 PM »

What you need are two long poles.  20ft poles are easy to find because plumbig pile and fence top rails come in 20 ft lenghts.  If you can screw two poles together, a large diameter on the bottom with a smaller one on top you have 40 feet.  Bury a large diameter pipe so that the long pole will drop into it.  Set two loong poles up on end.  install some guy wires (or guy ropes) and you've got it.  Put pulleys on the top of each pole

The ARRL antenna book has plans for a 40 foot mast made with 2x2 clear pine.  Looks like the eifle tower (sp?) with three curved sides.  But chain link fence parts might be cheaper than 240 linear feet of 2x2 lumber.  If yu guy it "right" you don't need a large diameter mast.  Use one tall mast and make an inverted V or two or three and keep the wire level.
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K7PEH
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« Reply #6 on: June 13, 2007, 09:52:52 PM »

And, also plant some trees so your great grand-children won't have the same problem.
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WR8D
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Posts: 165




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« Reply #7 on: June 14, 2007, 10:33:58 AM »

A telescopic mast pipe would do the trick. You could push the apex of the dipole up to about 35 feet and guy it off. Using four of them and you could put yourself up a nice loop antenna for any band. Or just one big loop fed with 450 ohm ladder line and work all bands. I use the loop myself but i've got all kinds of trees to guy it to.. but the telescopic mast pipe can give you all kinds of possibilities.

Good luck, John WR8D
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K7AAT
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« Reply #8 on: June 20, 2007, 05:43:27 PM »


   I'll add my vote for an Inverted V antenna.  While some here made comments saying you'll need at least 65' center mast to have an effective one,  I will certainly disagree.   Its good to keep the end points 10' or so off the ground,  but not absolutely,  nor is it absolutely necessary for the two wires to be 90 degrees.  120 degrees will work well too.   I'd suggest what others here have suggested,  either a push-up type TV steel telescopic mast,  or perhaps make a 35' center mast out of about 3 2x4x20' boards.  You can coax feed an inverted V and get pretty good results, especially if the length is short.  I'd suggest open ladder line instead, with a tuner,  which will get you all band operation.  good luck, with which ever way you go.  I think at your stage its more important to just get on the air rather than worry about antenna perfection.  

  Ed   K7AAT
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N2EY
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« Reply #9 on: July 13, 2007, 10:21:33 AM »

"An 80m inverted vee, for example, should be up about 65' above ground at its apex and each end should be at least 10' above ground, else it will work quite poorly and have a lot of earth-induced end-effects."

I disagree!

I have used an 80-40 trap inverted V at two houses and several Field Days with the apex no more than 40 feet off the ground, and have had very good results for domestic QSOs. As in several hundred CW SS QSOs with a 100 watt homebrew rig.

Of course the higher the better, and it's important to get the ends up at least 10 feet. But an inverted V up at least 35 feet is a good simple antenna for your situation.

You *will* need to adjust it for lowest SWR if you use coax feed, but that's not hard to do.  
 
"You could, of course, add a 20'-30' mast to the house and then use the top of that mast as the high point on an inverted vee."

That's what I did, except I only used about 15 feet of heavy-duty TV masting from Radio Shack. At the old house on RadioTelegraph Hill I used a vent-pipe mount,
and at my current QTH I use brackets meant for the side of the house. In both cases I used three brackets to spread out the stress.

Beyond about 15-20 feet, the mast would have to be guyed, which is impractical at my locations.

"If you do something like this, always install a pulley at the top of the mast, with a rope over the pulley, to raise and lower the antenna -- otherwise, any time you want to make an adjustment it will be a huge pain in the butt."

AGREED! But I gave up on pulleys long ago, and just use a large eyebolt. Eyebolts don't jam like pulleys and cost far less. Plus you can replace the halyard by splicing on a new one and pulling the whole works through. Be sure there are no sharp edges on the eyebolt to cut the line.  

Another poster suggested 4x4s sunk in the ground to hold the ends, and I agree. An 8 foot 4x4 with several feet in the ground, and a 2x4 extension, will do the job for the ends.

At my current location, the peak of the roof is at about 26 feet from ground. About 14 feet of mast extends beyond the peak. On 80 and 40 CW I can work practically everything I can hear. It's definitely not the best antenna in the world but it's the best I can do for those bands at this QTH.

In my case I used homebrew traps for 40 meters because a full-size 80 inverted V wouldn't fit. You could use separate fullsize 80 and 40 inverted Vs with a common feedpoint, spread out maypole fashion.

As another posted said, the important thing is to get on the air.

73 de Jim, N2EY
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