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We got back to the 4m hotfilm after the 3pm sounding. At new t0 we checked the resistance of the 4m probe (16 ohms, while the good probe at 2m was 7 ohms). Since we were measuring upstream of the bridge electronics, presumably this was a problem in the probe. We confirmed by switching the 4m and 2m probes to the opposite bridges, which resulted in good data from the 4m bridge and bad data from the 2m bridge. So I replaced the 4m probe (SF5) with a good spare (SF7), which is now giving good data. The wire on the bad SF5 probe is still intact, and visually it looks ok. I realized after getting back to base that I'd set the switches in the bridge wrong, so went back out to fix it. Data after 5:00 local is with the correct switch settings for SF7. Thanks to Steve for the remote support!
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