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I am planning for the future when I want to put up a good HF antenna to reach out as much as I can. I haven’t decided which antenna yet, though currently leaning towards the UrbanBeam. Anyway, I am trying to figure out how high I need to put it. For various reasons I am likely to put it on the hillside in the first picture below. This is on the west side of my property. the hill is about 35 feet above yard height with trees going considerably above that. The second photo is the view once I get above the trees, so you can see this hill is the only thing in the way for quite a distance.
My question is this. how high do I need to put the antenna? At the height of the top of the hill? Some distance above that height? Do I need to get above the trees?
I read a lot of different answers online so I thought I would ask others who live near me and understand our local ground type and tree types.
Thank you.
Hello Ian,
Given that you are looking at HF bands, the trees will not affect the performance of your antenna unless the limbs are close (same with 20 ft). If you are going to put up a tower though, you should plan to clear the trees so that a falling tree cannot hit the tower or cross a guy wire. A tree falling on a tower or guy wire can collapse your tower if the tree is even of modest size.
The general rule of thumb is that you want to place your antenna at least 1/2 wavelength above ground. This would be about 35 ft or more on 20m, 70 ft or more on 40m, etc. You will get a takeoff angle improvement in the specific downhill direction only. A good spot (based upon your picture) would be on the peak of the hill if you can make that work. This would probably optimize your takeoff angles in multiple directions and yield the best DX performance at your location.
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