Antenna spacing

[mustang_gt_350]

I currently have a vhf/uhf dual band base vertical that is 30ft to the bottom. I have it anchored into the facia board leading up to the eve of the house. I would like to install my soon to be arriving Sirio Gainmaster the same way on the other side of the eve. But i was wondering what the minimum spacing between the 2 that would be recommended. I really don't think i can pull off 40ft of mast as it would put too much of the mast above the anchor point. So i was thinking maybe drop the dual bander a few feet and add that few feet to the Gainmaster. I believe the dual band is 8ft tall. basically I'm asking what separation distance horizontally is recommended and if i can't get what is believed should be used if i can then make up for it by going higher over the top of the dual band?

 

[Tom Line]

My 2 meter ringo vertical, and A99 10/11 meter vertical, are about 15 feet apart and don't seem to mind. I only use one at a time. The A99 does seem to show higher swr due to a tree 20 feet away during the summer when the leaves are thick. It's all compromise, and an understanding how things interact is worth having. (A picture or sketch would help too.)

 

[mustang_gt_350]

Here is a quick crude sketch of what i'm talking about. Right now they are only about 4ft apart from each other. I don't really plan on having both in operation at the same time. I'm just trying to keep them from interfering with the others performance as much as i can. I was thinking about moving the VHF mast farther down the slope since the wind area of that antenna is less and it can afford a little less suport and maybe dropping it to only a few feet over the roof ridge. Then i can move the HF mast to the center of the peak and i may be able to add a few more feet to the mast thinking that maybe i can get the feed point of that gainmaster to just above the tip of the VHF antenna? But then again maybe the steel mast will affect the other more than just the antenna at the same height? Range for the vhf isn't really a issue since it hits repeaters and will most likely never be used for simplex use. However the HF will be so i was trying to make sure it was in the "open" more.