As title just wondered if any one has doubled up or try a different number of full size ground radials on a 5/8 vertical and see any difference in a model or real life????
I know the big mack had 6
I know the big mack had 6
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Anyone modeled or try 8 9feet radials on a 5/8 vertical
- Thread starter davev8
- Start date
Dave here are my Eznec models of a 5/8 wave 22.5' foot radiator with 4 x 9' compared to one with 8 x 9' radials at 36' feet high. I added an overlay of the patterns for easy comparison.
View attachment .625 wave with 4 and 8 x 9' radials compared.pdf
These modeling results will surprise many, and piss other's off that don't believe what they see here. The reason being this does not support the CB notions often noted...that such modifications like this produce remarkable advantages in both gain and angle.
There are technical differences to be noted here, but they are very small, and if we just would think about this fact, the differences being small, it probably makes total sense as technical things go.
I know there are others out there that will disagree with their words of experience, but I would like to see someone show me their models that disagree.
View attachment .625 wave with 4 and 8 x 9' radials compared.pdf
These modeling results will surprise many, and piss other's off that don't believe what they see here. The reason being this does not support the CB notions often noted...that such modifications like this produce remarkable advantages in both gain and angle.
There are technical differences to be noted here, but they are very small, and if we just would think about this fact, the differences being small, it probably makes total sense as technical things go.
I know there are others out there that will disagree with their words of experience, but I would like to see someone show me their models that disagree.
thanks for that Marconi ....have you tried only 3 to see what happens .
Altho i have come up with a very good neat idea to mont 4 radels but it not work with 3......but it will be interesting to know if their is no disadvantage with only 3
Altho i have come up with a very good neat idea to mont 4 radels but it not work with 3......but it will be interesting to know if their is no disadvantage with only 3
74, you will hear may stories of guys success building and matching their 5/8 wave, but IMO this is not as easy as it is suggested. Even bad matches can sometimes look good using an SWR meter.
You did not provide enough info for me, but there are guys here that read minds.
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Dave, 3 should be just about as good as 4, assuming maybe you get them evenly spaced around the feed point...which might not be as easy as it looks.
Did you understand what the models indicated? Did you notice the 8 showed the gain was a bit less, and did that confuse you?
Did you notice the currents on the mast for these models? This has an effect of making the gain look better sometimes, because the current on the mast is strong. The model with 8 probably decouples the mast from the radiator a bit better, less currents flowing on the mast, and that can make the model more accurate and seem to show less gain. However the model with 4 radials, was the opposite and thus there is more current on the mast, and that skews the pattern and the gain some...which is not always best.
Then the question arises, how do we ever know how this stuff works if we don't consider modeling? Even being really careful with real world observations can be misleading.
What did you experience using 3 radials only? What I said above may relate somehow to what you experienced using only 3 radials.
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Hi yes I did understand what the models are saying I did see the 8 radial antenna has slightly less gain and I noted the less currents on the mast… The outcome did not confuse me but if i was to hazard a guess before I see the models and I will have based my guess on no evidence so just a guess , I will have guessed 8 radials being better
I have not played with a 3 radial antenna (not at 9 feet) I was just thinking that if there was no loss of performance, a 3 radial will have less wind loading and be easy to handle and a fold over mast can be lower to the ground when folded with the radials 120 degrees apart instead of 90
Does efficiency play into any of the modelling?
AM broadcast towers typically have 120 radials beneath them. If it were better to stick with just four I'm sure they would not go through the added effort and expense.
AM broadcast towers typically have 120 radials beneath them. If it were better to stick with just four I'm sure they would not go through the added effort and expense.
Comparing the radials on an elevated antenna to the radials that are on or buried underneath the earth on a ground mounted installation is like comparing apples to oranges. They are both radials, but the presence of the earth for one set and lack thereof for the other makes a huge difference.
The DB
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