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Optimal height for inverted V

codeman

Recovering Crackerhead
Jul 10, 2011
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1,444
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I have used my dipole hung horizontally or in a sloper configuration from about 8 to about 12 foot high but I'm thinking about running it as a inverted V on a painter's pole front about 20 foot tall. I am looking for mostly dx contacts but would like to be able to talk to base stations on sideband that I talk with from time to time with the furthest being about 50 miles from me. I am able to talk with them from my pickup with a Uniden 980 with a RM Italy 203 and a Wilson 1000 mag mount. Should I be able to make local contact up to 50 miles or so with the inverted V at 20 feet?
 

An inverted V is about as close as you're gonna get to an Isotropic, that being a point in space which radiates out spherically exactly the same in all directions and angles.

- Pic from http://w4neq.com/htm/doublet.htm - but keep in mind, that's only 80 feet high on a band where a 1/4 wave is 60' long! This pattern would be equal to an Inverted V for 11m at approx only a 12' high apex! - Try to get it up to 36'-45' if possible.

rad_pat.jpg


The higher you get it the better, as in just about ANY antenna installation, but keep in mind when going from a flat-top dipole to a 90° Inverted V, you're losing 3dB in the broadside direction to pick up performance in the perpendicular directions.

PS: At 120° or a 60° angle per side, you'll have the flattest SWR when cut to R=52, X=0.

If you're trying to make an omni out of it, then get it as close to a 90° as possible (a 45° angle for both sides) and yes, HIGH AS YOU CAN!!

Remember, the higher you get it, the longer it will need to be to tune a flat SWR.

*EDIT* - avoid using non-insulator-broken metal guy wire, use dacron covered kevlar if you can.
 
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http://www.hamuniverse.com/wb4yjtdipolepatterns.html

Good reading, gives radiation patterns for dipoles and the best height for vswr match.

Depending on what you are wanting to do, height is a big factor, higher is not always better, look at the radiation patterns of the dipoles at different heights and you will notice deep nulls, that is what you want to avoid is the nulls.
Believe it or not 1/2 wl agl works awesome.
 
http://www.hamuniverse.com/wb4yjtdipolepatterns.html

Good reading, gives radiation patterns for dipoles and the best height for vswr match.

Depending on what you are wanting to do, height is a big factor, higher is not always better, look at the radiation patterns of the dipoles at different heights and you will notice deep nulls, that is what you want to avoid is the nulls.
Believe it or not 1/2 wl agl works awesome.
Hey there's John, one of the nicest guys I ever knew via HAMateur radio!

Only issue I see with that page is he's referring to flat top dipoles, not INV Vs, unless I read it wrong.
 
There's not really much difference between the two. A half wavelength in the clear (measured at the feedpoint) is probably the most convenient height - as in lowest for decent operation. You might find that higher is better for your location. HOW MUCH higher is something for you to determine by experimentation.
 
I have tried flat tops and inverted V's, from top band to 10 meters, multi band fan dipoles and the old ladderline fed multiband doublets.

End results the inverted V for ease of construction and impedance matching, coax fed, easy to install, one support required, few hundred feet of Dacron rope some 1:1 current baluns and you have an impressive start on an antenna farm.
 
"Above ground" doesn't necessarily mean measured from the lawn or soil directly below the feedpoint. It means above the actual RF-conducting depth, which depends on several things, including just where you are.

If you're in the Navy, out on a ship, then "above ground" can be measured from the surface of the ocean, OR from the deck on a larger ship such as an aircraft carrier. If you're out in the southwest desert, the water table is really deep in places, and that makes for a really deep ground. Places in central-to-east Texas have some of the best soil conditions for antenna work.
 
"Above ground" doesn't necessarily mean measured from the lawn or soil directly below the feedpoint. It means above the actual RF-conducting depth, which depends on several things, including just where you are.

If you're in the Navy, out on a ship, then "above ground" can be measured from the surface of the ocean, OR from the deck on a larger ship such as an aircraft carrier. If you're out in the southwest desert, the water table is really deep in places, and that makes for a really deep ground. Places in central-to-east Texas have some of the best soil conditions for antenna work.
Interesting!

73,
Brett
 
Just want to say thanks for all the information you guys gave. I will mount the inverted V at about 20 for now and see how that goes. Whenever I get a permanent house situation I will try mounting it on a longer push up pole.
Oh...and thanks for the links. I may even learn something.
 
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I will say this. Both horizontal dipoles I had up worked well at 18ft, but when I placed them at 35-40ft high off the ground, they worked much better. Less obstructions to deal with and also I was able to get the feed line to stay straight for a long ways. This helps a lot as well as having a good 1:1 matching balun or some good snap on ferrite chokes that fit snugly on coax. Also using a Low Pass Filter helps. Also make sure to use good weather proofing and to do it properly. Take your time here. It will save you a lot of headache later on!!
I preferred my horz dipoles versus the inverted V, but that is just a matter of opinion. Both types of dipoles work very well and are an easy way to make contacts around the world.
Also just FYI, both my dipoles were hung in 3 trees total. Almost an L type setup but, with some space between antennas. One pointed N/S and the other E/W. They do work well as they will cut a lot of background noise and also reject a lot of stations you might not want to talk to depending on the conditions. At any rate, just my experience with the 2 I had up. They have since come down as 11m DX has died, but will be repurposed for other bands! Be safe and have fun! Good day.
 
"Above ground" doesn't necessarily mean measured from the lawn or soil directly below the feedpoint. It means above the actual RF-conducting depth, which depends on several things, including just where you are.

If you're in the Navy, out on a ship, then "above ground" can be measured from the surface of the ocean, OR from the deck on a larger ship such as an aircraft carrier. If you're out in the southwest desert, the water table is really deep in places, and that makes for a really deep ground. Places in central-to-east Texas have some of the best soil conditions for antenna work.


Indeed. We are talking about RF ground in this case and depending on soil type it may be a few feet below the surface of the ground or many feet.
 
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Just want to say thanks for all the information you guys gave. I will mount the inverted V at about 20 for now and see how that goes. Whenever I get a permanent house situation I will try mounting it on a longer push up pole.
Oh...and thanks for the links. I may even learn something.
I used to string one up between the house and the kid's swingset. All of about 6 feet off the ground. Worked stateside dx with it, too. The most important thing is just to get on the air!

73,
Brett
 
Hello and thanks for all the good information on this thread. I am about to install my optimized multiband ZS6BKW dipole antenna and can do either horizontal or inverted V. I am located in Bucks County PA (East Coast) and only have one option to install E/W. I can get up as high as 46 foot. If I install horizontally will I get good DX to Western US and Europe with the ends pointer E/W? I know N/S will do very well based on propagation of the antenna but no one discusses how good DX will be off the ends. Thanks for your help!
 

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