Performance increase question

[Singularity35]

Additional height benefits you in two major ways, it allows you to clear obstacles, and increases the distance to the "visible horizon". How much that will benefit you depends on the natural and man-made structures in your area.

For example, if you are in the valley of a mountain range and the added height of your antenna still does not clear the nearby mountains it won't get you much. However, if you can raise the antenna above the mountain peaks it can make a world of difference. You may still have trouble communicating with those in neighboring valleys however, unless they have something like a repeater at the top of a mountain.

There is no easy cut and dry way to determine how well the added height of your antenna will benefit you. You being in a hilly area the benefit you see will be governed by the new height of the antenna verses the height of the hills/mountains in your area. The big question is does the antenna clear those hills/mountains or not.


The DB

Ok, thanks. That's clearer now. I'm not actually in a hilly area, I'm situated in a flat area around 2-3 km from the coast. A lot of foliage like mango trees and two or three story structures but not really close together. My antenna now is clearing the trees and the structures but not by a lot. The "highlands" I'm referring to are to the back of me around 10km or so but not obstructing where I want to operate in, which is maybe a 40 km radius around me. I'm getting heard and hearing stations at around that range but at only s2-s3 and these stations have 80 feet high masts at around the same elevation from sea level as I.

 

[Captain Kilowatt]

The gain you get from increasing height at VHF is more to do with clearing obstacles and, as has already been stated...
The DB

Exactly. Actual antenna gain does not go up by 6 dB however the signal may go up that much. I think perhaps there was a disconnect between what was said and what was meant. That's what I think anyway. There becomes a point of diminishing returns however as at VHF and up feedline loss can actually exceed any gains made by getting the antenna up higher unless you want to go ridiculous with with something like 1 5/8 heliax or bigger. $$$$

 

[Singularity35]

Exactly. Actual antenna gain does not go up by 6 dB however the signal may go up that much. I think perhaps there was a disconnect between what was said and what was meant. That's what I think anyway. There becomes a point of diminishing returns however as at VHF and up feedline loss can actually exceed any gains made by getting the antenna up higher unless you want to go ridiculous with with something like 1 5/8 heliax or bigger. $$$$

Thank you. Even I can understand that.

 

[Singularity35]

I was so dissatisfied with the performance of my old aerial. I was going to raise it up to 80 feet off the ground in the hope of a performance increase. Anyway, it was a pre-owned one and I decided to get a new aerial and test it at the same height before I extended the pole.

And wow! I'm really liking the performance of this new aerial that a friend made for me! I'm getting at least double the signal strength in RX and TX that I used to have for the same stations. And that's still the same height as the old one was at. I like it so much that I'm even rethinking raising it to 80 feet since I'm quite satisfied now.

Here's a pic.