Radar PM Test

[newthirdmate]

On my ship, every watch we perform a "PM test" on the radars. We have Furuno RCU-014 units, and this test takes about 30 seconds. When I asked the other guys on the ship what it is actually telling us, no one knows. When you perform it, it stops showing the regular screen and just brings up 2 semi-solid rings around 14 NM out. We take the range to the inner most circle and log it. Can anyone tell me what this is telling us, and if the range to this circle is the correct way to gauge the performance of anything? It hasn't changed once outside of human error the whole time I've been on here. I spoke with a port captain I know and he said on his ships the process takes 15 minutes, and is done once a day at noon. He couldn't really tell me what it was either, except that he thought it had something to do with the deterioration of the magnatron. Any knowledge would be appreciated, it seems pretty pointless to do something that no one knows how to read the results of...

[Ea$y Money]

Rcu-014 is your model number for your keyboard/trackball. Maybe some quality time wit your manual is in order. The performance monitor function is required on vessels over 300GT on international voyages. It's preset and no arc in the distance specified is telling you that you have a greater than 10db loss and your magnetron is bad. That's section 1.47.2 in the furuno manual for the 21/28's. Dust your manuals off and see if you can find some wording to that effect.