1)2 wave vertical dipole

[redbeast]

So I'm thinking of setting up a cheap easy base at the house, and have been researching starting with 1/2 wave vertical dipole. If my figuring is right, the dipole will top out right around 800 feet in elevation, with the base about 10' off the ground, and top about 30 feet up in a pine tree off a pulley....with weight at bottom. So my question is.....has anyone ever tried using two small turnbuckles at either end as part of the antenna, then to the insulators? My idea is, that would make tuning pretty damn easy, or is my thinking skewed? Figure pine tree about 30 feet from house, so coming off with the feed perpendicular no prob, and if the turnbuckles are part of the radiators tuning would be real easy, and the same with the insulators, as one end of the turnbuckles would be the end of the wire. Would appreciate some feedback. 73s, trouble

 

[BJ radionut]

What Band(s)???
10m?
Shorten these numbers about 5%...you have a 10m Ground plane antenna

 

[GlocknSpiel]

Your thinking isn't skewed at all. But there will be an issue dis-similar metals at the turnbuckle's connection point to the wire. That, and it's hardly worth the hassle in the end.

I would simply use the thickest wire you can get. The thicker, the more broad-banded the final antenna will be.

Then tune the wire for resonance on your favorite band & frequency.

Then get a tuner capable of coping with your planned max power level. This will allow full 10~12M band coverage.

Don't quote me on this, but Input impedance of a dipole is 200 Ohms --- At least, I KNOW it's not 50 Ohms, meaning, you'll have to make a 4:1 balun, or add a measured section of 400 ohm ladder line at the feedpoint, and a 1:1 choke if it's too noisy... Basically, I just described a "G5RV".
To simplify the calculations for wire and ladder line lengths to build it as a "G5RV", See link for those;

G5RV Multiband Antenna

The G5RV is a "multiband" dipole, but can be calculated for best performance on any single band desired using those calculations.

 

[redbeast]

Thanks for the input ....I was planning on 11 m to start out. Had thought about dissimilar metals, but figured if I used stainless turnbuckles and thick wire and soldered the wire to the buckle it would probably work. The other end of the buckle would be insulators, top to a pulley, and bottom with weight. My thinking was that the length would be a little more accurate than just folding the wire over an insulator, especially after it had been hanging for a while

 

[redbeast]

My info and research to date sez that I shouldn't need a choke or balun, as the antenna should be about 75 ohms, with a 50 ohm feed. Is that about right?? Nothing fancy, just straight ole 11 m dipole, right?

 

[GlocknSpiel]

My info and research to date sez that I shouldn't need a choke or balun, as the antenna should be about 75 ohms, with a 50 ohm feed. Is that about right?? Nothing fancy, just straight ole 11 m dipole, right?

I would just build it, test it, and see what difference I needed to make up to get the input impedance to 50 ohms. I predict, it WILL be an issue, but an easy one to address, once it is a known value.

 

[redbeast]

Strikes me now I probably should have posted in the cb antenna section, my bad haven't been around for a while

 

[HarryUSA]

First of all, a vertical dipole is highly impractical unless you can keep the feedline at a right angle to the radiators for at least 1/2 a wave length. Secondly, the impedance of a dipole that close to the ground on 11M, will likely be less than 50 Ohms. Thirdly, I don't understand how your dipole can "top-out" at 800' of elevation, when you start at 10' and go to 30' at the other end? Do you mean you are at 800' above MSL?

For vertical antennas, the most practical is an end-fed 1/2 wave...go buy an old Antron 99 or BigStick, and host it into the upper branches of the tree.

 

[Captain Kilowatt]

You can run the feedline up inside the lower half if you use copper pipe, and that should be the side connected to the shield of the cable. This will decouple the feedline from the antenna rather well.

 

[AudioShockwav]

Here is some info that may be of interest.
Yes it's multi band but has good construction ideas.

Vertical Dipole - 10 Through 20 meters - One Half Wave or Longer - KL7JR

 

[Dusty1USA]

For an 11 meter dipole in an inverted V orientation, I just copied the length for the wires from the ones they have on sale on Ebay, bought a 1:1 balun rated to 500 watts for $40 off Amazon, measured out the correct amount of no. 12 AWG copper wire (insulated) and connected that to the balun, strung it up between a couple of oak trees. SWR is 1.0 or less than 1 across all 40 channels.
I do believe it hears and talks a little better than the Tram 1498 I have on the roof.
Cool talking Dx on an antenna you kinda put together yourself and didn't cost much.

 

[davev8]

Thanks for the input ....I was planning on 11 m to start out. Had thought about dissimilar metals, but figured if I used stainless turnbuckles and thick wire and soldered the wire to the buckle it would probably work. The other end of the buckle would be insulators, top to a pulley, and bottom with weight. My thinking was that the length would be a little more accurate than just folding the wire over an insulator, especially after it had been hanging for a while

surprisingly stainless don't play nice with other metals..a galvanized turnbuckle will be better and use tinned wire

 

[Crawdad]

You can run the feedline up inside the lower half if you use copper pipe, and that should be the side connected to the shield of the cable. This will decouple the feedline from the antenna rather well.

What a great tip!

7 3

 

[Crawdad]

For an 11 meter dipole in an inverted V orientation, I just copied the length for the wires from the ones they have on sale on Ebay, bought a 1:1 balun rated to 500 watts for $40 off Amazon, measured out the correct amount of no. 12 AWG copper wire (insulated) and connected that to the balun, strung it up between a couple of oak trees. SWR is 1.0 or less than 1 across all 40 channels.
I do believe it hears and talks a little better than the Tram 1498 I have on the roof.
Cool talking Dx on an antenna you kinda put together yourself and didn't cost much.

Next time time anyone wants to homebrew a monoband Center-Fed Halfwave Dipole you don't have to copy SleazeBay or anyone else. Simply do a little simple math:

468/Freq. in MHz= total length of both poles in feet.
234/Freq. in MHz= length of one pole in feet. Just cut 2 @ this length.

Just plug your favorite frequency into the equation and cut your wire. Depending on your end attachments you may want to add a little to those lengths. 14 or 12 AWG wire is perfect, cheap, low weight and will give you all the <1.5 SWR bandwidth you need for the entire 11m band, plus some.

For Inverted Vs some folks add 5% to those lengths, I found when cutting for several HF monoband band Vs, that subtracting 5% got me much closer to the correct length for easier tuning. YMMV.

Despite the ancient (and incorrect) CB myths about dipoles and wire antennas, you'll end up with a highly efficient, balanced antenna that will outperform most manufactured, overpriced 11m antennas currently available, especially the fiberglass-tube end-fed verticals with a 26 gauge wire inside.

A 1:1 balun/Common Mode Current choke is also fairly easy to homebrew, cheaper and higher quality than many on the market.
They can be made using coax:
LMR240-Ultra Flex. A little pricey but worth it.

or Bifilar wound with solid copper wire pulled from Romex house wire:
Stick it in a watertight box, makes a good, easy feedpoint for a dipole. Both are Fair-Rite FT240-43 mix ferrite toroids. $10-$12ea. on Crapazon.

7 3

 

[wavrider]

vertical dipole.
As CK mentioned feed the coax through the bottom element
copper, emt conduit works great also.
at end of bottom element wrap an ugly choke or 1:1 balun.
"Reference gainmaster antenna for the rf choke"
I prefer rg6 or rg11 for coax to a dipole.
Better vswr match, broader band width.