As Fish40 says you can use that range ring mod to guestimate ranges, but watch out! I am fairly sure that the radar's range settings of 8,000, 20,000 and 80,000 are in fact in meters, not yards, so that's another nice layer of uncertainty. You can use the PPI screen to get rough bearing to your target and range can be guestimated from the PPI or the 'A' Scope. The 'A' scope in theory should offer better precision, as it's twice the length, but it's logorithmic, so it's not so accurate at longer ranges. The 'A' scope gives bearings that are arced to the left, in version 1.4, by 9 degrees (it should really be 5 degrees), meaning a target at a bearing of 180 degrees will show on the 'A' Scope from 171 degrees to 180. I don't know why it does this, as the sonar give an arc where the target is in the centre of the bearing readings. Take successive readings for range and bearing and plot them - make a note of the times you take the readings. Once you've got a plot, you can calculate speed from distance/time.
Does anyone else actually plot using readings taken from the radar?
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