yes i got a better reception when i moved the antenna nearer the window. 
i've been using the antenna for many months all the while no issue, donno why today ch8 got problem. donno if its ch8 problem or what
now i try moving the antenna back to original position, back to normal, but sometimes signal still break off
		
		
	 
It all depends on a good day, your current level may be average.
For DVB there is what we call digital cliff. If you are at borderline a little change in acquire signal, you will lose it.
This is normal. I've noticed during rainy season, When i closed my window, my DVB-T2 signal attenuates abit more than when it is on a sunny day. Antenna is in same position.
You can use your TV signal strength meter display to check your reception. Move your antenna around .....etc  you will see varying level of signal. This is especially true for marginal and above average acquired signal areas.
You need to have a good Eb/No Margin for perfect TV reception for good and bad weather.