Major
Minor Sectors
Minor Isolated (tower/trees/etc): 3 lines look like blockage by trees or towers near the radar (approx azimuths of 108, 127 and 232 deg).
Significant over lake at low elevations (winter). Sea clutter is also seen in summer, when higher anlges are used, but less strongly.
Distance to horizon from an on-line calculator = 68 km (http://www.ringbell.co.uk/info/hdist.htm, apparently geometric with no refraction, so add approx 10% at radar wavelength.)
There is a wind farm immediately to the south east.
The radar often sees ships on Lake Huron. Long term rainfall statistics tend to show shipping channels.
Radar echo stats from non-precipitation days
In summer Dopvol1_A accumulation images can show ship tracks. They start around 55km at 210deg (near WhiteFish Pt) which is the closest point to Sault Ste Marie that the radar can see the lake surface.