I have no experience with radar but I do have some questions for those
of you who do.

Is there a device that detects radar so that you can tell from a long
distance if someone with radar is illuminating you? This would be
sorta like a police radar detector.

What is the time average power of most consumer radar systems?
Do they have a "warm-up" time?
Do you use it continously?
How far away will it detect:
1. A ship
2. A buoy with a corner reflector
3. A small sailboat with radar reflector
4. A small sailboat WITHOUT radar reflector
How does chop affect its performance?
Does bad weather affect it?