This whole radar system is rediculous. How the hell can shipboard radar be effected by bombing HQ??!!
Do away with HQ controlled bar-dar, make each base an independent radar site. Each 4 sector block should have a master radar station that can be knocked out of service, blacking out those sector's bar-dar. However, maximum height to be below dar should be reduced to 50 feet. This will allow for different methods of stealth attacks. Do away with blinking map icons altogether and bar-dar in enemy sectors. The enemy should not know what is flying at your bases until they actually get there.
In other words, attackers must sneak in very low under dar, kill sector block radar station which then allows the sectors to be transited without detection, unless they fly within the range of field radar.
HQ should be a command, control and communications center. If it is damaged or destroyed, radar will only be available in the sector block you are in, and all country text (not field text or radio coms) are down until HQ is repaired. This will introduce real command and control problems to game play and add a measure of additional "real feel" to the game.
My regards,
Widewing