2024 Nov 12
Neil, Fil, and Jim installed an HS-1 geophone in the biergarten (image attached). HS-1 is threaded to plate and plate is double-sided taped to the floor. Signal given was non-existent. Must install pre-amplifier to boost signal.
2024 Nov 13
Neil and Jim installed an amplifier (SR560) to boost HS-1 signal (images attached). Circuitry checked to ensure signal makes it to the racks. However, when left alone there is no signal coming through (image attached, see blue line labelled ADC_5_29). We suspect the HS-1 is dead. HS-1 and amplifier are now out of LVEA, HS-1's baseplate is still installed. We can check one or two more things, or wait for more HS-1s to compare.
Fil and I tried again today, we couldn't get this sensor to work. We started from the PEM rack in the CER, plugging the HS1 through the SR560 into the L4C interface chassis, confirming the HS1 would see something when we tapped it. We then moved out to the PEM bulkhead by HAM4, again confirmed the HS1/SR560 combo still showed signal when tapping the HS1. Then we moved to the biergaren and plugged in the HS1/SR560 right next to the other seismometers. While watching the readout in the DAQ of the HS1 and one of the Guralps I have connected to the PEM AA, we could see that both sensors could see when I slapped the ground near the seismometers, but the signal was barely above what looks like electronics noise on the HS1, while the Guralp showed lots of signal that looked like ground motion. We tried gains from 50-200 on the SR560, none of them really seemed to improve the snr of the HS1. The HS1 is still plugged in over night, but I don't think this particular sensor is going to measure much ground motion.
One check for broken sensors - A useful check is to be sure you can feel the mass moving when the HS-1 is in the correct orientation. A gentle shake in the vertical, inverted, and horizontal orientations will quickly reveal which orientation is correct.