With my temporary setup (antenna on upstairs window sill) I feel lucky if I see more than 5 or 6 flights simultaneously, but a lot of that is down to terrain masking and surrounding houses within 30 feet. My best direction appears to show traffic out to about 30-35nm at FL400, but again that's a terrain limitation. The worst direction (which might be terrain, might be few aircraft passing in that direction and might be the Cardington airship sheds at 250ft high x 900ft long at 1 mile range) is about 4-5nm, which is a little odd because there is one clear arc.
Essentially this is down to being at 100ft asl with various surrounding terrain that is 150-200ft above me within a few miles in several directions.
I will do better with an external antenna, but in any case Sunday's log showed 650 flights.