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Dipole Leg Direction

kd0fx

W9WDX Amateur Radio Club Member
Aug 16, 2009
160
2
28
EN10bt
I'd like some clarification on the leg direction of dipoles. I may need to erect a dipole with the legs going in different directions, IE one leg going south and one leg going east (and somewhat sloping ala inverted V). To my understanding that is OK as long as I keep 90 degrees between the two directions. What does that do to the directivity of the dipole? I guess I'd mostly like to run my gain east/west.
 

how high is the center and ends, and what bands will it operate on?

I'm looking to place a G5RV with the center about 35' high (so the ladder feed point will be near the ground), and the ends sloping to a 10' termination. I will have some structures nearby but I can't get away from that. I guess I'm asking from a perfect free space perspective.

I'd like to get the whole 80-10 but I'll have to see how it performs in meat space and try to modify it after that.
 
Why not put it up in a particular configuration, use it, and SEE just how it performs? It's pretty difficult to answer specific questions about a specific installation from 1500 miles away.

If it seems to work but you want to see if it can be improved, then change ONE thing at a time. Go slowly and keep good detailed notes.
 
Why not put it up in a particular configuration, use it, and SEE just how it performs? It's pretty difficult to answer specific questions about a specific installation from 1500 miles away.

If it seems to work but you want to see if it can be improved, then change ONE thing at a time. Go slowly and keep good detailed notes.

Yes, that's what I'm going to do. I just thought someone might have some insight to this particular question of leg direction in any nonspecific installation. I'm not looking to reinvent the wheel so any head start is good in my book.
 
The nulls tend to be off the ends of a dipole. Unless you can put it up at height of one wavelength at the frequency your using, the radiation pattern is going to be more like a big donut and not very directional anyway.

As an example: A full wavelength at 14.250 Mhz is about 65 feet.

Your G5RV at 35 feet isn't going to show directivity on any band. So just install it in the best spot and enjoy.

BTW: The G5RV was designed as a 20 meter antenna but you see it marketed as an all bander. You should't need a tuner on 20m with it but you will to operate any other band.
 
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The nulls tend to be off the ends of a dipole. Unless you can put it up at height of one wavelength at the frequency your using, the radiation pattern is going to be more like a big donut and not very directional anyway. Just put it up as high as you can and don't worry too much about orientation.

As an example: A full wavelength at 14.250 Mhz is about 65 feet.

Makes sense to me. I'm going to get some wire and make me an antenna this weekend. As long as it's not blizzarding I should be able to get it up. Thanks.
 
I'd like some clarification on the leg direction of dipoles. I may need to erect a dipole with the legs going in different directions, IE one leg going south and one leg going east (and somewhat sloping ala inverted V). To my understanding that is OK as long as I keep 90 degrees between the two directions. What does that do to the directivity of the dipole? I guess I'd mostly like to run my gain east/west.

the highest current in the dipole is in the first half of the middle - about 70% so if you can get that part strait say the middle 50% at a perfect 180 degrees, then bend the ends 45-90 degrees you should like the performance, and you can even coil some of the ends on 2 inch gray pvc to shorten it in your yard but leave about 2-3 feet strait at the ends and try to match both sides. dont use black abs because it has a high carbon content.
if you just put up a wire curt for a 1/4 wave on each side, you will have a good tuning antenna. if you use stranded wire and or wire that is coated with some kind of insulation then you will want to cut it a little short, about 95% of the 234/freq formula.
if you can get the middle around a 90-125 degree downward vee then it should tune a low swr and act more non-directional. you can put a bunch of dipoles together in the middle and stretch them different directions (if you have the room) and cover all the bands with a low swr. there not that picky about bending the legs this way or that way but the more of the middle you can get at 180 degrees the better it will preform. if your going to use a tuner to tune one wire dipole for all bands then use 300-450 ohm twin lead or ladder line and a manual 'balanced' tuner like a dentron and you will get the best performence. using coax down to a tuner for a multi-band dipole wont perform near as well
 
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I'm using an AT-200.
I can reconsider my antenna design. I've gone outside with my measuring tape and realize I have a crap ton more space than I had thought. I'd still have to have the legs off kilter but I can do a 1/2 wave 160M if I want to. I'm limited on how high I can get, but I can sure spread out. It might not be optimal but until I can afford to have someone put up a tall tower for me something is better than nothing.
 
I'm using an AT-200.
I can reconsider my antenna design. I've gone outside with my measuring tape and realize I have a crap ton more space than I had thought. I'd still have to have the legs off kilter but I can do a 1/2 wave 160M if I want to. I'm limited on how high I can get, but I can sure spread out. It might not be optimal but until I can afford to have someone put up a tall tower for me something is better than nothing.

"You can also use the AT-200ProII with longwires, random wires and antennas fed with ladder line with the optional LDG balun."
if your only running 250w or less just get some tv twin lead (the thicker black stuff is beefier then the flat brown type) and it will save you cash compared to 450 ohm but if you can aford it then the stranded wireman brand 450 ohm is xlnt
 
Sorry, it's a Kenwood AT-200. But those LDG baluns would still work very well with it. I've already got plenty of 450 ladder line too. Really just need to get the appropriate length of wire for the legs.
 
Sorry, it's a Kenwood AT-200. But those LDG baluns would still work very well with it. I've already got plenty of 450 ladder line too. Really just need to get the appropriate length of wire for the legs.
the last one i helped biuld was 57 feet for 3.9 using home depo 12ga insulated and stranded wire. depending on your terrain, height, vee angle, your results may vary, but theres a jumping off point
 

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