In WW2 radars were also used to detect ships more than 100 miles away. It would be good to have a new structure in coastal bases with shore batteries representing surface radar, as well as in fleets. For gameplay purposes, its range may be reduced to 25 miles.
Also, one of the most important info delivered by air defence radars was altitude of the contacts. Some filters may be added to the clipboard map to show only > 0k contacts (default selection) > 5k contacts, > 10k, > 15k, >20k and > 25k (may be implemented with a single vertical slider). Historically, these radars were able to give accurate information about contacts height up to 40k.
