[CA] [CA11] AIS false positive alarms

[heysteve]

I have an AIS700 with all the latest updates and notice that in high traffic areas I get lots of false positive alarms. I believe the reason is the alarm will activate if the traffic CPA is less than a configured range OR the TCPA is less than a configured interval. Do I understand this correctly?

The result of the OR condition is that I often get alarms for close traffic (small CPA) but with a TCPA in the hours range. For example, I recently passed behind an anchored freighter (about .1 nm) with a TCPA of over 4 hours and yet still got an alarm. As a result, I must set my CPA alarm distance setting to the minimum (.1 nm) when in fact I'd like to use a larger value.

Is this expected behavior? Is there some other way to prevent these nuisance alarms?