How come antenna recption is better close to the ground

Yes i was wondering why my antenna has a better signal gain at the ground level that it does when i rise it 10 to 20 ft in the air?

curt,

You are probably experiencing a phenominon known as Ground Waves. Here is a website that shows someone taking advantage of them.
Classic Pete: Once More, Out To The DTV Fringe

On the other hand, you may have 'cleaner' signals with your antenna down low. Signal strength has little to do with the reception of digital signals. A clean low-strength signal will always trump a "noisy" high-strength signal.

Jim

This effect is often called ground bounce.

Ground gain and radiation angle at VHF

You can often see the signal enhancement from ground reflection (the reflected signal is added to the direct signal) when you try different antenna heights using the interactive mapping option for tvfool.com and note an increase in signal strength at certain heights.

this phenomen just in VHF can happen, what can happen in UHF

Diffraction is the likely answer, especially with intervening terrain.

then i get my channels due to any weird reason just the signal fluctuactes highly even if put record a tv show can see later break ups in the tv show recorded