Vertical and horizontal beam mounting

[532woodchuck]

Hi all, I've got a maco m106 hot fed on an 70 ft tower an 10 ft up a 12 ft mast pole. In the vertical plane, had it there now for 3 years and recently been wanting a horizontal beam too. So I found an old maco m105... So now comes the question "where should I put it"? I of course would like it up there under the 6 but don't know if they would interfere with each other? How bad? Anybody done this? I don't have any room under it, I'm talking about 6“ from the lower element tips of the 6. I do have another tower I could use of needed but only at about 45` after I install said tower... Somewhere? Any thoughts, anybody know how to figure this out on a program, I have one but not sure how to run it with two antennas on it? Thanks for your knowledge....!

 

[GnG8d]

Put them on the same boom.

 

[Captain Kilowatt]

Dual polarity beams have been around for decades. I used one in the late 70's and 80's. It was a Wilson Shooting Star. Avanti made the Moonraker series and there were many more. They were all mounted on the same boom. With the elements at right angles interaction is minimal.

 

[SuperNasty]

A friend of mine had a 3 element sirio beam horizontally, he purchased another one removed the fittings and elements and as suggested fitted them to the same boom successfully in the vertical configuration, with a switch box at the transceiver he goes from one polarity to the other instantly and gets the best of both worlds!

 

[nitroturbo4u]

vertical beam

Just dont use metal pipe in the vertical field.Of the beam that is.:bdh:

 

[TIN_CAN]

Just dont use metal pipe in the vertical field.Of the beam that is.:bdh:

Hog Wash! op:

 

[GnG8d]

Vertical M105 with no mast ............




Vertical M105 with mast ............

 

[Captain Kilowatt]

I don't believe that plot. It shows almost zero F/B with a metal mast. I ran dual polarity beams with about half the vertical elements below the top of the tower and with a metal mast and I had good F/B. Quite hood in fact. On VHF I would agree but not HF/CB.

 

[GnG8d]

I don't believe that plot. It shows almost zero F/B with a metal mast. I ran dual polarity beams with about half the vertical elements below the top of the tower and with a metal mast and I had good F/B. Quite hood in fact. On VHF I would agree but not HF/CB.

*shrugs* I don't know? That's a 2" diameter mast extending 6" above the boom. Maybe someone running EZNEC can try it and see what they get.

You also have to remember that cross polarization by the math shows infinite signal loss/attenuation. But in the real world you'd never get that to happen, even a couple of degrees makes a difference and most people would agree that ~20dB should be expected.

So in the simulation everything is perfectly lined up and most real world setups aren't. That would be my best best stab at it.

I'll go back and offset it the diameter of the mast ............ sit tight

mast .....


3" offset mast


Didn't amount to a hill of beans really. Someone smarter than me is going to have to answer it, hehe

 

[GnG8d]

I just rotated the yagi 3* off of vertical and it didn't make much difference so I didn't screen capture it.

Here is a quad and a yagi, both vertical with/without a mast .............

yagi


quad

 

[Marconi]

I just rotated the yagi 3* off of vertical and it didn't make much difference so I didn't screen capture it.

Here is a quad and a yagi, both vertical with/without a mast .............

yagi
View attachment 12396

quad
View attachment 12397

359, my Eznec models don't show the big difference in patterns between a yagi "with and without a mast" as your post does. I also believe real world testing pretty much proves that something is wrong or at least different with your model.

Can you post an image of your antenna model?

I can't be sure, but in looking at the task bar in your pattern the "Near Field" button is highlighted differently than the other buttons noted. Is you model set to scan near field results? Maybe this might be the difference I'm getting.

 

[GnG8d]

Alright, I'm not going to mess with this anymore unless someone wants my source code to figure out where I've messed up. I certainly like the vertical pattern for DX since it lacks the deep nulls of the horizontal pattern, but unless I could mount it on a non-conductive mast I'd have to pass.

This is a vertical M104 with no mast, with a 2" mast, with a 2" mast and boom rotated 5* off of vertical, with a 2" mast and boom rotated 10* off of vertical.

 

[GnG8d]

Can you post an image of your antenna model?


I can't be sure, but in looking at the task bar in your pattern the "Near Field" button is highlighted differently than the other buttons noted. Is you model set to scan near field results? Maybe this might be the difference I'm getting.

Those are far field results and the near field button is greyed out.

 

[Marconi]

Alright, I'm not going to mess with this anymore unless someone wants my source code to figure out where I've messed up. I certainly like the vertical pattern for DX since it lacks the deep nulls of the horizontal pattern, but unless I could mount it on a non-conductive mast I'd have to pass.

This is a vertical M104 with no mast, with a 2" mast, with a 2" mast and boom rotated 5* off of vertical, with a 2" mast and boom rotated 10* off of vertical.

View attachment 12398

Sorry if I upset you 359. I just wondered why I never saw the results that you posted above. I wish I understood 4nec2 better so I could try and help us figure out why we are seeing the differences I noted.

I asked you a question about the model being set to Near Field and that is the only thing I question regarding your results as a possible difference in results.

Here is my model of the idea of a beam with and without a mast attached.

View attachment 359 model of beams.pdf

 

[Marconi]

Well, let me change my model to vertical and I'll get back.

How far do you have the mast set from the driver?