If you're using aa 144MHz IF, there's a chance you're seeing IM products between your mixer LO and one of the 3G base station channels.   I'd have to look up the channel that cases the problems, but it was bad here until I added an additional filter in the Rx chain

Andy

www.g4jnt.com

On Wed, 16 Sep 2020 at 20:13, G0FVI via groups.io <Andrew.gilfillan=ntlworld.com@groups.io> wrote:

I'm still learning being relatively new to uwaves so apologies if this question seems a bit 'dumb'. I'm noticing fairly high noise levels on 23cm UKAC from my /P location (S5) but it's not constant in all directions and tails off to zero in several directions particularly due east to the continent (ground slope away to east and there are no obvious nearby man made sources of noise although there are HT pylons about 100 yards away). I'm not getting this at home with the same setup mounted on mast at about 35 feet (/P mast is only 20 feet), so I'm guessing it is perhaps ground noise? 

Andy G0FVI