Spent 2.5 hours re-running line 1200E on a dipole-dipole IP survey (25 m spacing) after a beautiful chargeability high, which turned out to be our steel tape draped across two current electrodes. Anyone else ever inverted a textbook ‘disseminated sulphides’ target that was the field truck idling 8 m from the Rx?
Been there — after a ‘beautiful chargeability high’ fooled me, I added one habit: if the Rx is within about 10 m of a vehicle, do a 60-second engine-off repeat on the nearest dipole pair before moving on. It takes less than the 2.5 hours you spent and has killed a few truck-and-tape ghosts for me. @OP do you keep a fiberglass tape on the crew now to dodge the steel-across-current trick?
On a 25 m dipo–dipo line I once chased a beauty that turned out to be the winch cable under the Rx. Now I do a quick 20 s “flip-current sanity check” at the hot station — reverse current twice and make sure chargeability flips cleanly; if it doesn’t, I immediately scan for stray metal like a steel tape or an idling truck instead of re-running 2.5 hours on line 1200E. Caveat: it won’t flag slow DC drift from fences, but it’s caught most phantoms — did you try it when the truck was 8 m off?
My quick fix after a ‘steel tape’ surprise on a 25 m dipo was to enforce a 5 m metal-free bubble around the current electrodes and run one ‘hands-up’ stack: crew stash metal and step 15–20 m clear, then restack at the hot station. @OP do you log C1/C2 contact R per station — a paired drop is a tell that something’s bridging. It costs about 60 s but saved me another 2.5 hours of chasing ghosts.
Quick trick: I keep a cheap AM radio — if it chatters near the hot station, we kill engines, grab a 20 s current-off blank, then do a one-station pull-back; nine times out of ten the ‘sulphides’ evaporate. Your 60 s engine-off repeat is gold, @sadams85; anyone else using the AM-radio sniff test or do you prefer a fast decay-window check?