This is an alternate 2 spawn spot very similar to the ruins spot listed in the wiki. Here is a link to the wiki guide:
http://wiki.project1999.com/A_sarnak_courier
Spawn these the same way, gathering all the potential ph mobs and killing near the ph spawn area, then wait and see if you got them both.
-806, -2720, 100 and -951, -2587, 100 are the spawn locations shown with the corpses in the screenshot below. They spawn just as fast as the phs at ruins.
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There is another ph spot that I haven't really screwed around with yet on the other side of the field. I don't know if it's only a single or not.
I'll edit this later to add more info. 10 Hours tonight no ring.