5. If your radar has manual tuning, adjust it for maximum return. Do not use the tuning control to reduce clutter as it will reduce reception of everything.
6. Reduce the gain to where you still see light speckling across the whole screen. Getting rid of all speckling may also eliminate a weak target.
7. Next, adjust the screen brightness or brilliance to best suit the day or night conditions.
For more details, look in the manual for your model radar.