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Dipole questions
- Thread starter IronGuts
- Start date
Hey Doc,
Somethings not right!
Looking at the two radiation plots the horizontal looks to be a dipole, whereas the vertical appears to be a ground mounted 1/4 wave vertical. This would account for the stronger gain for the dipole vs the half of a dipole (1/4 wave ground plane) for the vertical pattern. I think a dipole would have the same gain vertically or horizontally mounted, but the patterns don't match up as that to me. Do you agree?
Mike
Somethings not right!
Looking at the two radiation plots the horizontal looks to be a dipole, whereas the vertical appears to be a ground mounted 1/4 wave vertical. This would account for the stronger gain for the dipole vs the half of a dipole (1/4 wave ground plane) for the vertical pattern. I think a dipole would have the same gain vertically or horizontally mounted, but the patterns don't match up as that to me. Do you agree?
Mike
It's the same antenna rotated through 90 degrees, a vertical dipole does not have the same gain as a horizontal dipole other than in free space, antennas do not exist in free space, they are influenced by the ground, and horizontal antennas more so than vertical
Maybe you need to explain, if what you are saying is that you made an assumption about a simple model I had presented, then that's ok, I do it all the time
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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
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
... antennas do not exist in free space, they are influenced by the ground, and horizontal antennas more so than vertical
READ what you just said,.......... a Horiz ant IS affected more by the ground,........... and that causes about a 7 Db LOSS, not gain!
the difference in gain between the antenna over a perfect ground and over a real ground is large. At low heights the antenna radiates about like an isotropic radiator at low radiation angles, with about a 7 dB losss to the ground.
it is aparent that mounting the dipole vertically reduces the sensitivity to the ground conditions and lessens the ground loss.
With respect, I suggest a little reading may lead to enlightenment, I'm not going to argue with you because you believe yourself to be right, I've identified a couple of sources of information that are pertinent to the subject, if you don't have a copy, I'll send you the relevant pages, but here's one graphic from the ARRL antenna handbook that may be of use:
This is a horizontal dipole at 1WL above average ground, the outer trace is above perfect ground
I wouldn't disagree, I answered a chaps question as to whether vertical or horizontal is best, I like a freebie, and for DX I'd prefer a horizontal dipole at height rather than a vertical dipole for the reasons explained, it seems some people have taken issue with that
The above said, I much prefer a vertical by the sea, which is why most of my radio time IS by the sea
soooooooooooo,.............exactly what does that have to do with your statement that a horiz dipole has more gain than a vert dipole?
those big green things that are blocking your view of the forrest,........ they are called trees.
those big green things that are blocking your view of the forrest,........ they are called trees.