Before moving up from Oro Valley in 2019 I regularly monitored A-A intercept exercises in southern AZ....Bigfoot which I think was an AWAC type flight would periodically track & intercept small aircraft & other unknowns in the AZ\Mexico border area up to around the Casa Grande airspace...my question is: Has anyone heard the Bigfoot callsign lately or is this activity no longer occurring, at least in the form it once did? Or has the callsigns changed? I had to stop my monitoring for a few years due to medical issues but have now resumed...any input is welcome