OK. Here goes.
o turn off all sea and rain a/c
o turn off any filters, IR rejection, etc.
o set to longest range
o advance the gain until noise appears
o back it off slightly so just a bit of noise remains
o go to shortest range
o find a channel or creek with some markers or other good targets
o advance the sea a/c until the picture cleans up with clearly defined targets
o reduce the a/c until there are false echos and ghosts around a marker, target etc.
o add just enough back in to remove the false echos
As you move on either side of the correct setting, it will be possible to zero in on the right amount of a/c. Too much and you will lose nearby targets. Not enough and you will have too much false return.
As always, experiment, and run the radar during good visible conditions so you will become familar with how things look. This way you will be prepared when visibility is poor.
