Dipole questions

[hookedon6]

Here's another graphic for you chaps to consider, both models have a minimum height of 0.5m, so when you see 0m height, it is actually 0.5m, this model has the horizontal dipole at approximately 1/2WL high and I've varied the height of the vertical dipole from 0.5m up to 5.5m, this is so we can compare the antennas at current maxima and minima

All antenna parameters are the same, no correction for VSWR, so length, diameter, segments etc are all the same, it makes sense of course to correct these if you were to deploy the antenna

Still not sure about the gain of a horizontal dipole, don't take my word for it, how about that of the ARRL antenna handbook, check out chapter 3 page 12 and the graphic on page 18.

Model this over saltwater or a perfect ground, and the tables turn, I'd have the vertical this time

the parameters are NOT the same. you changed the HoG.

GARBAGE IN,..... GARBAGE OUT!

 

[The DB]

ARRL antenna handbook, check out chapter 3 page 12 and the graphic on page 18.

You might want to be more specific on which version of the book, my 22'nd edition ARRL Antenna Book, Chapter 3 page 12 finishes up a section called "Real Wire Radial Systems" and starts a section called "Optimizing Radial Lengths". I did read through the entire chapter, and while there are sections on both vertical and horizontal antennas, the two were not directly compared or were their plots shown directly against each other. Apparently we have two different versions of the book.

It does explain how the effects of ground affect both types of antennas in different sections of the chapter, and there are some definite differences, but that is as close to a direct comparison as it gets. It does not directly compare one polarization to the other, and doesn't have the two polarizations in the same figure.

I would also point out that it assumes ground mounted vertical antennas in most of its discussions, which will have some distinct differences from an elevated vertical ground plane antenna.

Returning to the discussion at hand, when looking at height, typically it is easier for someone to get a vertical antenna mounted higher then a horizontal antenna, in some cases significantly. This would only help the vertical antenna.

There is also the fact that you are effectively comparing apples and oranges. Horizontal and vertical antennas have different properties, and if you have two antennas will complement each other very well. But because of the different properties presented directly comparing the antennas becomes very difficult when comparing for DX purposes. Other variables will have more of an effect, and these variables can make the antenna with more gain (whichever one it may be) near useless while the antenna with less gain has no problems at all.

In any case, either should work, but if the op can have both a vertical and horizontal, and easily switch between the two antennas, that will work even better.


The DB

 

[northern35s]

the parameters are NOT the same. you changed the HoG.

GARBAGE IN,..... GARBAGE OUT!

I'm prepared to discuss most things with most people, but that has to be a two way street, if you resort to ad-hominem then there really isn't any point :headbang

 

[QROdx]

and you said i wouldn't need the popcorn.... this has been interesting... I knew it would be.

I won't lie, I asked you to explain just to see if you understood the mechanics of how they differ.
Seems like you do

Each antenna has it's place. Each can work DX. It really all boils down to what you're after and what works best for you.

At first I was wondering if you were comparing a 1/4λ vertical instead of a vertical dipole to the horizontal dipole until you finally mentioned it was indeed a dipole vs dipole.
If you were to have used a 1/4λ vertical in the comparison I would say that it isn't fair to compare a 1/4λ vertical against a dipole because they are two different creatures.
But if you were to use two verticals mounted near ground, spaced appropriately for the frequency, you will see radiation pattern that almost equals that of a dipole mounted 1/4λ AGL.
Granted it still lacks the "gain" but you have an almost exact pattern.

I've never compared different antennas at the same height because I know they each operate differently and one prefers a different location compared to the other.
You can easily change the pattern of the antenna just by raising or lowering it a few feet due to the mirror effect that you get from the ground.

My biggest concerns are nulls. I could care less if some super-dipole offered 87dB gain at 43 degrees especially when I am trying to make contact with someone at 14 degrees right where a null is located.


back to my popcorn.......

 

[northern35s]

You might want to be more specific on which version of the book, my 22'nd edition ARRL Antenna Book, Chapter 3 page 12 finishes up a section called "Real Wire Radial Systems" and starts a section called "Optimizing Radial Lengths". I did read through the entire chapter, and while there are sections on both vertical and horizontal antennas, the two were not directly compared or were their plots shown directly against each other. Apparently we have two different versions of the book.

It does explain how the effects of ground affect both types of antennas in different sections of the chapter, and there are some definite differences, but that is as close to a direct comparison as it gets. It does not directly compare one polarization to the other, and doesn't have the two polarizations in the same figure.

I would also point out that it assumes ground mounted vertical antennas in most of its discussions, which will have some distinct differences from an elevated vertical ground plane antenna.

Returning to the discussion at hand, when looking at height, typically it is easier for someone to get a vertical antenna mounted higher then a horizontal antenna, in some cases significantly. This would only help the vertical antenna.

There is also the fact that you are effectively comparing apples and oranges. Horizontal and vertical antennas have different properties, and if you have two antennas will complement each other very well. But because of the different properties presented directly comparing the antennas becomes very difficult when comparing for DX purposes. Other variables will have more of an effect, and these variables can make the antenna with more gain (whichever one it may be) near useless while the antenna with less gain has no problems at all.

In any case, either should work, but if the op can have both a vertical and horizontal, and easily switch between the two antennas, that will work even better.


The DB

21st edition here.

I've read a good chunk of the book and hoped that by showing a simple graphic, with the details underneath, that people who maybe hadn't spent some time studying the subject could see what I was talking about.

One poster questioned the accuracy, whilst making an assumption about height, one poster decided to attack me rather than discuss the physics, even though I had offered to help with his understanding.

I had a 4 element monobander at 13m high, this was great for DX, but sometimes my vertical worked out better on shorter distances, this is all down to the arrival angle (a subject on it's own). when I work backpack portable by the sea I am relying on the very low angle of radiation of my vertical antenna, good enough to work Western Australia, some 16,000 miles, with just 500mW SSB, or with 100W working W6 long path, almost 20,000 miles, a horizontal dipole would be no match on the beach

As for having both, hell yeah, one is never enough

 

[W5LZ]

I feel like I need to acknowledge that you were right in that I did make an assumption when I shouldn't have. I'm not used to seeing measurements given in metrics. From there, I still believe those plots don't accurately describe the typical shapes of radiation patterns of a dipole antenna as given.
- 'Doc

 

[northern35s]

I feel like I need to acknowledge that you were right in that I did make an assumption when I shouldn't have. I'm not used to seeing measurements given in metrics. From there, I still believe those plots don't accurately describe the typical shapes of radiation patterns of a dipole antenna as given.
- 'Doc

I've lived with then metric system since being a youngun, however I still talk about miles to the gallon rather than the litre, I'm 5'10", and my car will do 140mph on a good day, however my antenna mast is 12m high and I have a 1 metre pole out of the top of that, go figure

As for the radiation pattern, I checked to make sure I hadn't overlooked something, I modeled them again using both Eznec and MMANA, same result, here's a graphic from the ARRL antenna handbook that pretty much matches my first graphic, minus the vert of course:

Don't get me wrong, I don't profess to be any kind of an antenna guru, to be honest I consider myself to know very little, but I love to learn something new

 

[RADIOOMAN]

Looks to me like the vertical dipole is the better of the two antennas.

 

[wavrider]

A dipole is a dipole is a dipole, no matter what frequency you are working.

The gain, direction of radiation all depends on height above ground. Taken into consideration no buildings or other sources of obstruction to block the signal.

DX is DX. It all depends on the AOA angle of arrival of the received signal.

With that said a dipole at .5 WL is a good DX antenna, It will not have the low angle of radiation of a vertical at .5WL .

If the vertical can be installed 1wl above ground it will work great DX, so will a dipole.

It depends on frequency also, 27mhz, my vertical at 70' will equal or perform better than four element yagi at 40'.

The 40 meter yagi at 50' will not out perform the 40 meter half wave vertical ground mounted for DX.

The characteristics of vertical antennas is dependent on the frequency being used.

The higher above ground that a vertical is installed the less effect the ground has on it.

I agree a vertical on the beach is a great DX antenna. Many DXpeditions only use verticals. Because they work at sea level on the beach.

http://www.eham.net/articles/23758

another look at dipole vs vertical.

Good thread and good topic.