I got Mmana-gal working in linux, so I can use it if need be. Man its been a while since I used this program. I had to really search around to find the place to put in the feed point... Unfortunately there is nothing here that shows the phase of the signal, at least that I can see. When I get a chance I'll make up some models in 4nec2 which can show both the current and phase data together and post them.
Thanks The DB. Then it clears it up and yes I am aware of the small "out of phase" portion in a 5/8 wave antenna, (though that is not what I understand out of phase to mean as out of phase implies 2 separate waves and I or current is 1 sinus wave) This portion of current at the bottom seems to drag the pattern down or flatten if you like...and produce its gain at a lower angle. At least according to the simplistic explanation I read.
I used the antenna modeling vernacular of phase. In this case, while we talk about the phase and what part of the cycle the current is in, what we are really referring to is the phase of the RF said currents create. The currents of the two halves of a full sine wave, for example, while not out of phase in and of themselves, will create RF that is out of phase with each other. The nec2 modeling software itself uses this same vernacular.
So a full wave dipole can exist after all.
Yes, and they can be made even longer than that. For example, look up the Extended Double Zepp.
That being said, while dipole is technically correct, and many will not bat an eye to its use, there are some that specifically call a center fed half wavelength antenna a "dipole", and everything else a "doublet". Its going back to the vernacular thing I mentioned above. Both terms mean the same thing, its just some people use them differently.
It is still curious that MMANA GAL basic allows an end fed full wave wire to be made and in fact shows a radiation pattern when there should be none.
There is just one other issue though... this is a sine wave representing current alone and a sine wave is 1 wave.. and it must by definition have a + and - side.. how can these different polarities cancel each other if one either lags or foregoes the other in time and space ?... For phase cancellation 2 waves need to be in opposing polarity at the exactly the same place in time and space to cancel.
The reason this happens is the two out of phase currents are on different parts of the antenna, and they are far enough apart to be electrically significant. Look at ladder line for example, or any other open wire feed line. The two wires in said feed lines are almost on top of each other, comparatively speaking. They do a much better job at cancelling out the other wire. But the end fed full wavelength antenna has its currents that try and oppose one another much further apart. They do still have the cancellation effect, but only in certain points of space, namely the points that have the same distance from each half of the antenna, which is broadside to the antenna. As you leave that direction and, in this case, move higher, something else happens. The distance relationship from the two halfs of the antenna to the same point changes, and thus the phase of RF from the two parts of the antenna don't perfectly cancel. If the two points are far enough apart, as they are here, you get a peak radiation at a much higher angle where, instead of canceling, they radiation from the two parts of the antenna actually end up benefitting each other.
So, in a nut shell they cancel in certain directions, and add up in others. All antenna phasing works like this.
In fact, the modeling programs that we use (namely any program that uses MOM, or Method of Moments) does this on a much larger scale. These programs break up the antenna into parts called segments (for these models it wouldn't surprise me if there was more than 100), then calculate the current and phase data for each segment and where the segment is in a 3d space, then uses that data to calculate the antenna's radiation pattern.
The radio rabbit hole is a deep one with many twists and turns.
Yes, and it never ends. I'm still traveling down it myself. It goes much deeper than most people realize.
Going back to an earlier part in your post, kinda off topic but...
Then it clears it up and yes I am aware of the small "out of phase" portion in a 5/8 wave antenna, ***removed some text here*** This portion of current at the bottom seems to drag the pattern down or flatten if you like...and produce its gain at a lower angle. At least according to the simplistic explanation I read.
I think its a bit off topic, but here is a suggestion to try. Model an end fed 5/8 wavelengths antenna in freespace, compare that to and end fed half wavelength antenna also in freespace, and then tell me what you see in regards to the angle of peak gain, if you want you can even post the results here for everyone to see. There is an interesting bit here that most people get exactly wrong about 5/8 wavelength antennas...
The DB
