Filter My Radar - Never seen any aircraft.

Hi, I have been submitting data for several weeks now, just this weekend I have raised my antenna to the highest point above my home, my plan is to go even higher.

I have filtered my radar on the website but have never seen anything tracked by my radar, is there anything I can do to improve the chances of it being shown? I live in central UK so is there simply too many people contributing locally? and my tracking is approximately 157nm (based on the stats on my account page), Millions of messages per day.

Any feedback would be great.

Thanks :)