Love to see how that works out in the real world, there's a lot of handwaving in the description (works best on low frequencies, ground wave, near the transmitter) and even then it's a degree or so of {lat,lon}gitude, which is 60-ish miles, so might work in sparsely populated areas with lots of KiwiSDR boxes (yes, a contradiction), hopefully the OP gets to ask Mike for his guide and can narrow it down, please report back!

73, Willie N1JBJ