I found this hard copy I printed of the vertical Moxon I made in error. It shows the error I was trying to describe.
View attachment Moxon model with error..pdf
View attachment Moxon model with error..pdf
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Made a Moxon
- Thread starter HomerBB
- Start date
Yep. I can see the error in the diagram. The halves of the antenna are separated.
Here is the Moxon on the straightened mast that was bent at the top when we suffered tornadic conditions here a week ago with the Vector 4000 on the mast. It is @ 38' at the wire elements:
Here is the Moxon on the straightened mast that was bent at the top when we suffered tornadic conditions here a week ago with the Vector 4000 on the mast. It is @ 38' at the wire elements:
Yep when I tried to change the Moxon from horizontal to vertical by using the "Rotate Wires" function in Eznec, the results didn't turn out exactly like I planned. And, the antenna view I was using didn't reflect the problem either...as you could notice in the model I posted.
I checked the antenna results for match and pattern, and they seem about the same as the Moxon without the mast, so I figured I was good to go. The Moxon with a mast looked like it would work.
Then Henry posted his results, saying this setup would not work in the real world or using Eznec. So, on finding my error, without correcting and checking further, I posted that Henry was probably right.
However later, when I fixed the problem I found the mast idea still showed the model to work...and showed results similar to what the Moxon showed without the mast. I have no idea what Henry did that showed the model going to heck in a hand basket. But, by the time I realized my error and fixed it...I decided to just let the subject go figuring...there were probably much better ways to support a vertical Moxon.
I concluded that I can't test in the real world, and IMO that is always necessary before relying on modeling results...so why add further confusion by changing my mind again, and continuing to talk.
I checked the antenna results for match and pattern, and they seem about the same as the Moxon without the mast, so I figured I was good to go. The Moxon with a mast looked like it would work.
Then Henry posted his results, saying this setup would not work in the real world or using Eznec. So, on finding my error, without correcting and checking further, I posted that Henry was probably right.
However later, when I fixed the problem I found the mast idea still showed the model to work...and showed results similar to what the Moxon showed without the mast. I have no idea what Henry did that showed the model going to heck in a hand basket. But, by the time I realized my error and fixed it...I decided to just let the subject go figuring...there were probably much better ways to support a vertical Moxon.
I concluded that I can't test in the real world, and IMO that is always necessary before relying on modeling results...so why add further confusion by changing my mind again, and continuing to talk.
I have seen photos of the Moxon vertical, and of it being two together with a vertical and a horizontal setup each, like a rectangular +
What comments I've read on the vertical is that PVC or fiberglass mast was used withing the rectangle.
If one was made with fishing poles it could be suspended off to the side of the mast.
What comments I've read on the vertical is that PVC or fiberglass mast was used withing the rectangle.
If one was made with fishing poles it could be suspended off to the side of the mast.
I didn't know about a dual polarity Moxon.
Common sense would suggest to me that a non radiating support would be best in this case and maybe even necessary. So, I was surprised when using a mast in the vertical model...that it seemed to work OK. I had never tried it so I just took Henry's words for it...that it did not work in a real world test.
I seem to recall someone suggesting a mast between the Moxon elements, so I tried it using Eznec. Albeit I made an error, I still think it might be possible to support one that way even using a reflective mast.
In the case of your design I would agree it would seem best to mount it to the side of a support mast.
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Well Homer, I don't know how you see this idea working out, but this link convinces me that a metal mast might workout just fine when supporting a vertical Moxon. Apparently Larry didn't see any ill-affects of the mast being inside the antenna loop, albeit the mast wasn't all the way to the top...like the one on my model.
Like I've said already, I too saw very little change in the results for my vertical models, with and without the mast. <gotproof>
In light of what Henry told us about this idea not working using Eznec, and Larry suggesting his idea works, I wonder who is right?
Keep us posted.
Like I've said already, I too saw very little change in the results for my vertical models, with and without the mast. <gotproof>
In light of what Henry told us about this idea not working using Eznec, and Larry suggesting his idea works, I wonder who is right?
Keep us posted.
Hello,
Its always good to question antenna theory/and real live measurements.
Just to give a couple: so far I do understand:
The quad is much better than a yagi...and of course it does have a lower take off angle
No..we dont need radials on a vertical,and...yes the antron has indeed 9,9dBI gain.
And if we just would expend the tube size of the “radial basket” of the 2nd clone of the Vector 4000 it will be a noticable “audio gain” improvement.
Heck im almost forget that SWR is the most important factor and what was that other word…efficiency ?..
Perhaps I can now add to that list:
A metal tube in the same electrical field as the antenna will have very little effect ?
No, without joking. Should we really go there ?
A metal mast will (at least in most cases) not work fine Marconi…
there might be some “hot spots” where the effect is minimised.
But sadly Im afraid in most cases (if not all) performance will drop .
If you would measure what is going on, im confident you will find out there are far better options like a vertical polarised quad for example…that will do what you are expecting.
Kind regards,
H.
Its always good to question antenna theory/and real live measurements.
Just to give a couple: so far I do understand:
The quad is much better than a yagi...and of course it does have a lower take off angle
No..we dont need radials on a vertical,and...yes the antron has indeed 9,9dBI gain.
And if we just would expend the tube size of the “radial basket” of the 2nd clone of the Vector 4000 it will be a noticable “audio gain” improvement.
Heck im almost forget that SWR is the most important factor and what was that other word…efficiency ?..
Perhaps I can now add to that list:
A metal tube in the same electrical field as the antenna will have very little effect ?
No, without joking. Should we really go there ?
A metal mast will (at least in most cases) not work fine Marconi…
there might be some “hot spots” where the effect is minimised.
But sadly Im afraid in most cases (if not all) performance will drop .
If you would measure what is going on, im confident you will find out there are far better options like a vertical polarised quad for example…that will do what you are expecting.
Kind regards,
H.
B
BOOTY MONSTER
Guest
haven't herd that one before . i've read the suggestion that there might be some additional signal strength gain from making the basket ring larger , but i don't recall anyone finding the right diameter to achieve that yet .
Henry, I was going on my model, and the model had a mistake.
When I fixed the model, the rejection was worse like you said, and the gain was down some but was still over 5.0 dbi. The match was a little off, but not terrible indicating less than 1.40 SWR. The antenna pattern showed to still have gain...with low angled directionality.
My first post stated that my common sense told me it would be better to make all supporting elements non-conductive.
When I saw Homer's link to Larry's dual polarity setup I saw his antenna design, and the mast part was similar to what I modeled. He said it worked fine, but he did not give us much info, so whatever happened...Larry didn't complain.
I took this to mean there wasn't much difference, and again that was much like what my models showed.
When I fixed the model, the rejection was worse like you said, and the gain was down some but was still over 5.0 dbi. The match was a little off, but not terrible indicating less than 1.40 SWR. The antenna pattern showed to still have gain...with low angled directionality.
My first post stated that my common sense told me it would be better to make all supporting elements non-conductive.
When I saw Homer's link to Larry's dual polarity setup I saw his antenna design, and the mast part was similar to what I modeled. He said it worked fine, but he did not give us much info, so whatever happened...Larry didn't complain.
I took this to mean there wasn't much difference, and again that was much like what my models showed.
I haven't either, Booty.
But I have heard of using thicker radials in the cone, improving the cross pieces that hold them, reinforcing the lower section of the vertical by doubling the tubing there, and raising the cross piece up along the vertical to add strength to the lower section. And the proof of it is my antenna survived a serious storm.
If an antenna is optimized it will hear better in all likelihood than the same antenna if it is not optimized . . . or what's the point?
B
BOOTY MONSTER
Guest
i used some of those suggestions on mine . i'll be double walling the bottom 3 section on mine when i put it back up and it already has a beefy X and bottom basket/feed-point bracket .. and i copied your mobile stud for the coax/gamma connector . i recall a post saying not to put the X too high because the higher up the basket it is the more potential for arcing when it's wet if using high power . given our modest power it's probably/hopefully not a issue for us . i think i'll use your new X idea after i get mine back up and feel up to playing with it again , but i'll put it at the top so i don't have to worry about the placement of the x bowing the basket elements in or out when playing with their lengths .
sorry for hijacking your thread
sorry for hijacking your thread
Henry is well able to talk for himself and I understood his point, but you guys amaze me that you have never heard of Jo Gunn's idea about their larger sized elements contributing to the increased audio gain they claim, and that gain being due to how the increased RF is produced from the increased surface of their larger elements.
<gotproof> Check it out here: Home
Homer, right or wrong, Jo Gunn claims you can hear the difference over their competition. Is that what you're talking about...regarding optimizing your antenna? Or, are you talking about improving bandwidth which is easy to measure?
I also understand that some modeling programs claim to be able to optimize specific performance characteristics, but can you share with us how you do that?
<gotproof> Check it out here: Home
Homer, right or wrong, Jo Gunn claims you can hear the difference over their competition. Is that what you're talking about...regarding optimizing your antenna? Or, are you talking about improving bandwidth which is easy to measure?
I also understand that some modeling programs claim to be able to optimize specific performance characteristics, but can you share with us how you do that?
B
BOOTY MONSTER
Guest
No, I was simply referring to how we went back over the Q2v4k to make it as near perfect as I could with respect to the original specs. I had stated the Sigma version seemed to be less on RX/TX than the Qv4k I had made, and one of my goals was to replicate the performance I'd had with it when rebuilding the second Moxon. I believe whatever the reason, I achieved just that.
No, I hadn't paid any attention to the Jo Gunn claims, and I apparently thought Henry was actually saying what I thought he was when he wrote this - "And if we just would expend the tube size of the “radial basket” of the 2nd clone of the Vector 4000 it will be a noticable “audio gain” improvement." I missed the Jo Gunn connection.
No, I hadn't paid any attention to the Jo Gunn claims, and I apparently thought Henry was actually saying what I thought he was when he wrote this - "And if we just would expend the tube size of the “radial basket” of the 2nd clone of the Vector 4000 it will be a noticable “audio gain” improvement." I missed the Jo Gunn connection.