stacking maco beams

[niterider]

Are you planning on stacking them vertically (one on top of another) or side by side? There is pattern differences between each. I would say vertical stacking would be the easiest, as you would need a very strong horizontal mast to keep the seperation length right.

 

[HiDef]

Are you planning on stacking them vertically (one on top of another) or side by side? There is pattern differences between each. I would say vertical stacking would be the easiest, as you would need a very strong horizontal mast to keep the seperation length right.

How about the little problem of the vertical metallic mast interfering with the vertical elements in the same plane? A vertical stack of 2 antennas would have to deal with this. A horozantal stack of 2 verticals would not.

 

[W5LZ]

HiDef,
The vertical polarization would mean that there would be some detrimental affect from the supporting mast. But, if you need vertical polarization for whatever reason, I think the 20 dB difference between vert/horz would out weigh that mast's affect on the radiation pattern. Wouldn't you?
And while there can be some difference between a vertical stack and side-by-side stacks, I think the mechanical aspects of that vertical stacking sort of rules it's self out, at least it would for me and HF beams!
None of that says it can't be done, and probably has, but I'm not real sure it would be worth it. You think?
- 'Doc

 

[HiDef]

HiDef,
The vertical polarization would mean that there would be some detrimental affect from the supporting mast. But, if you need vertical polarization for whatever reason, I think the 20 dB difference between vert/horz would out weigh that mast's affect on the radiation pattern. Wouldn't you?
And while there can be some difference between a vertical stack and side-by-side stacks, I think the mechanical aspects of that vertical stacking sort of rules it's self out, at least it would for me and HF beams!
None of that says it can't be done, and probably has, but I'm not real sure it would be worth it. You think?
- 'Doc

I try to think. Sometimes it works. Yes, cross polarization introduces about 20dB system loss. That was not the issue. The guy asked about verticals for local work.

If he has problems with local QRM the answer is more in what he can notch out rather than maximum forward gain. A Maco 5 element yagi has very deep nulls at 90 degrees each side of the forward lobe. Point that at the offender and the signal will pretty much vanish. It also helps makes direction finding practical.

When antennas are stacked for optimum forward gain the number of side nulls increases and they are not as deep. This gets worse with compromised stacking. I'd avoid stacking altogether in a situation where rejection was important. At these frequencys stacking is a whole lot of work. The rotor will get beat up. Not worth the hassle for under 3 dB IMHO. One could (as suggested) put up a quad and get about the same increase in forward gain as stacking with a given boom length.

Time energy and money could be used to put the proposed antenna higher and/or use lower loss cable as opposed to stacking.

 

[HiDef]

BTW, I mentioned horizontal stacking of antennas only to illustrate the mast interference problem of verticals stacked vertically not as a solution to the original problem.

 

[silvereagleii]

maybe reading this will help you make your decision what you want to do hope this helps or at least answers some of your questions The Ultimate Guide to 11 Meter CB Antennas

 

[dennis4040]

maybe reading this will help you make your decision what you want to do hope this helps or at least answers some of your questions The Ultimate Guide to 11 Meter CB Antennas

A guy not far from me has stacked 7s vert and one flat on another tower. I think he uses the maco stacking kit but will have to ask him to make sure. He goes by Makers Mark. Said he gets about 2 db more out the front over a single 7. You may get 3db with more spaceing. Very tight patern.

Does anyone know how to get hold of Makers Mark from Indiana?
I would love to know how he setup the vertical stack.
Thanks, dennis

 

[vkrules]

13ft is about right for the phasing harness but you want 18 ft or more for the spacing. If you are really doing this don't forget to post some pics

 

[Shadetree Mechanic]

Bump, stack em if if ya got em.