Call sign VIKNG76. It sounds like military, but I wasn’t able to find any history on it. Any idea what dude was doing for a few hours? Instrument calibration? Pilot training?
Did you pick up the ICAO code?
I cut that part out of the screen shot to make it smaller. 
Any way to look back in Piaware or Virtual Radar to see a track from several hours ago?
From my list of callsigns:
VIKING KC-135R 92nd Wing, Fairchild AFB, WA
VIKING F-18 VMFA(AW)-225 MCAS MIRAMAR
VIKING F/A-18F VFA-122 NAS Lemoore, CA
VIKING A-10 172ND FS MI ANG BATTLE CREEK MI
VIKING F-22 Langley AFB VA
VIKING C-130, 934th AW Minneapolis-St Paul MN
VIKING OPS 934th AW CP Minneapolis-St Paul MN
The icon shows FL119 and apparently transmitting ADS-B, would that be military over the populated area? Might be high for aerial photography. DEA wouldn’t be advertizing their location in all likelihood. BTHOM.
Another VIKNG displaying the same pattern. ICAO = AE272C. Nuclear monitoring, perhaps? Note nuclear power plant to the northeast.
AE272C is a CN-235 based out of Pope AFB, 427th SOS.
Interesting. By the way, can you point me to a web site where I can look up ICAO codes?
If I track an aircraft that doesn’t exist in my database, I will google the phase, for example, “AE272C aircraft”. This normally give various sites that have reference to the hexcode that I am looking for.
Marty
Good information. Thanks!
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AE272C was circling above KRNT today. Later landed at KBFI.