Field Notes

West Pond: 2023-05-31 12:45:00 (DOY 151)
Author: Daphne Szutu
Others: Carlos, Jerry

Summary: No power at tower--fixed temporarily

2023-05-31
West Pond

Carlos, Jerry Sun, and I arrived at 12:45 PDT. It's been a cool spring so it was a pleasant day, mild and clear with a slight breeze. Jerry is an undergrad student exploring ideas for his senior thesis and today was his first time in the field. The wetland is continuing to green up and the staff gauge read 48cm.

There was no power upon arrival. The GHG USB stick showed many small truncated files in the last 2 weeks, and no data at all in the last week since 2023-05-23. I checked the solar charge controller, battery voltage = 26V, solar amps = 0, load amps = 0. Carlos checked the orange (24V) terminal strip in the met box and measured ~1V. The green (12V) terminal strip had 0V. We called Joe and he said there was a short somewhere between the battery and the load. I turned the load off on the charge controller and on again. Carlos confirmed there was still no power at the tower.

Since Robert and I had worked on trimming the willow trees last time, at first I thought we had nicked the power cable. The power cable wends through the many trunks of the willow tree before it connects to another cable via wire nuts. The second cable runs through conduit under the road and then sans conduit through the tule canopy to the battery box. I disconnected the wire nuts, Carlos turned on the load from the charge controller, and I measured 24V on the wire running from under the road. He turned the load off again, although I was still measuring 16V on the wire running from under the road.

So the short is somewhere between the wire nuts and the tower. We tried to pull the power cable out through the tree branches, but it was stuck because one of the trees has grown around the cable. I, Jerry, and then finally Carlos worked on trimming the wire just past the tree (ended up using garden shears instead of the diagonal cutters). Jerry pulled the power cable free of the willows and inspected it, but didn't find any fresh nicks (some old damage had already been wrapped in electrical tape).

There was plenty of slack wire on the tower side so we were able to connect the two parts of the power cable together. Carlos connected them with a pluggable screw terminal I stole from the met box, which only had 2 slots so we left the ground wires disconnected for now. The spare screw terminals in the toolbox were all for smaller gauge wires. Jerry wrapped it all up in electrical tape so the screw terminal would not unplug. We pushed the power cable just off the road. The levee road was mowed in the last few months and the weeds are still short, so I don't think anyone is going to mow in the next 2 weeks.

I checked the data at the tower and all seemed to be running now. I downloaded USB GHG and picam data. I thought I downloaded the met data but it doesn't seem to have made it onto sneakernet. The wash reservoir was full so I did not refill. Carlos cleaned flux and rad sensors.

The 7500 read: 415ppm CO2, 560mmol/m3 H2O, 25.6C, 100.9kPa, 101SS--102 after cleaning
The 7700 read: 1.99ppm CH4, 13RSSI--90 after cleaning (low initial RSSI b/c power was off)

We left at 14:50 PDT.

Joe and I will be back in two weeks to implement a more permanent fix for the power. Probably involving some conduit.

0 photos found

8 sets found

Can't check WP_DO
1 WP_DO graphs found