the gold frequency that you are used are so diffrent
630.980.610 Hz = 631Mhz & 6,20 KHz of Geo , 59.5 Khz of Steban device &
i don't understand what's the correct frequency , maybe it response to each frequency
i have similar experience with Gravitator ,sometimes it works very well but sometimes detect nothing .

but the

explorer always detects the coin