This slide depicts the programming of preferred assignments in nine sort boxes around the Dansville long-range radar. The Dansville radar itself, which I colored green, is up in the north-northwest part of the middle box. The radar sort boxes which I depicted in green, which match the Dansville radar's icon color, show that the preferred radar for those sort boxes is the "green" Dansville radar. Similarly boxes colored red are utilizing the "red" Clearfield radar as the preferred radar. All boxes colored purple have the "purple" shaded Utica radar as their preferred assignment. Get the idea?
First of all, notice than none of the nine sort boxes are shaded purple. Therefore, even though Utica's coverage extends over this area, it is not used as preferred coverage. The data is tossed into the ole bit bucket. However, the box that overlies the Dansville radar is shaded red, which is the same color I depicted the Clearfield long-range radar. Therefore, any aircraft in this 256 square mile area must been "seen" by Clearfield to be presented for display, because as you recall from our earlier discussion, one-and-only-one radar site is used at any one time. The Clearfield radar site is just over 100 miles south of the Dansville radar site.
Why is it done this way? This is done to make it so an aircraft that flies directly over a radar site, through it's cone-of-silence, will still be displayed, as the radar can't look directly above itself. That was the adaptation (assignments) back till shortly after my "Real Targets - Unreal Displays" paper was published. In the Center enroute environment, it is typical for a site far away to be assigned as the preferred site, so as to compensate for the cone-of-silence. By the way, before we move on, notice my depiction of the difference in size between a cone-of-silence and the 256 square mile radar sort box. A cone-of-silence increases in size the higher one goes. I used a 5 mile diameter for the cone for comparison with the size of a sort box. So, as you can see, we're correcting for a problem in roughly 20 square miles of airspace, but our fix actually covers 256 square miles.
Let's look at this from a different angle...
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