We may be talking two different things here (and I'll let the more
knowledgeable correct me if I'm wrong).
I "know" of two types of blanking. In one case the transmitter is switched
off during a certain arc of the scanner rotation.
The other "blanking" is done by the computer to blank off the picture over
certain areas of the scan rotation where the radar image would just show a
more or less solid land return of no value to the viewer.
In both cases these are used on shore based sets and to be honest I can see
little if any value for underway shipboard use.
Where I am we are using a shorebased ECDIS system which blanks the radar
image overlay on the chart plotter over land though it does show the radar
image of the offshore islands.

otn


My Furuno 1623 has adjustable blanking, and it's a very inexpensive unit.
I'd be
quite surprised to find a consumer unit that didn't have this ability.

CWM