Homestake meeting minutes, 02/05/15

Attending: Gary, Terry, Daniel, Jan, Noah, Vuk, Tanner, Pat, Nelson

Homestake wiki: https://zzz.physics.umn.edu/groups/homestake/home

Our agenda:

1) Homestake status

Vuk: All instrumentation from PASSCAL has arrived, total 25 seismometers and digitizers. During the last visit we solved the problem of GPS signal transmission to the underground stations. The solution required converting between the TTL format (used by transceivers) and the RS232 format (used by Q330) for the 1PPS signal. Installed instrumentation at the 300, 800, and three 4100 stations, and implemented the solution at the existing 3 4850 stations. Also solved the radio problem for the surface stations, the Ross and Yates surface stations are now operating. Also installed instruments at the Water Treatment Plant station, but the radio signal was not working probably because of the line-of-sight issue. In total, we have 10 working stations (8 underground and 2 surface) plus one more surface station that is not communicating with the main computer. The main computer has reboot problems, trying to get help from Jaret, but at the moment the data is not flowing.

Gary: the radio problem is solvable. Probably need a higher antenna, maybe using a piece of pipe. Could also use a higher gain antenna. Not the configuration problem, probably not interference problem. Should ask PASSCAL for high gain antennas for this site and for the Riolite Ridge. They should have them on hand, could ask for this in a couple of weeks. May want to combine the shipment with something else, we need solar boxes (some went underground), maybe additional brackets.

Daniel and Tanner to compile what else we need from PASSCAL.

Daniel/Gary: Data flow currently going from Homestake to Indiana to Caltech. Want to divert the flow to UMN, and Caltech and Indiana will get it from there. Tanner and Gary will need to do this.

2) Planning next visit: probably Mar 23 - Apr 3

Vuk: Asked SURF whether these two weeks would work, waiting for reply. The idea would be to have the following coverage:

Week 1: Tanner, Pat, Victor Week 2: Tanner, Daniel, Vuk (probably only 3-4 days)

What we want to accomplish:

• Build and install the 4850 station near 17 ledge, including huts and the battery pad (if necessary).
• Install the two 2000ft stations. Power and network should be available by the time we arrive (network is currently down).
• Install the 1700 station nearest to Yates. Will not have network.
• Potentially install another station at 2000, further northwest. Discussions with SURF are in progress on this.
• Fix the radio issue with the water treatment plant station.
• Potentially install other surface stations, depending on weather.
• Improve the stability of the data flow.

Gary: for the highschool site, we should probably set up the station and deal with the communication later. Maybe this could be folded into our plan, maybe get students involved.

Vuk: should probably start talking with their IT people to see if we can set up the communication too.

Vuk summarized the proposed battery operation/charging: batterydeploymentproposal.pdf

Terry: may need different circuit breakers, all 4 chargers may be too much for a single circuit breaker. Will have to check with the mine. Also may have to put the batteries in tubs, but could stack them in a pyramid configuration. Also need the cable length from batteries to the station.

Gary: can trains carry 20 of these batteries? Should check with the mine.

Gary: may want to have a good hand truck to move them around at the site.

3) Analysis of existing data

1. Estimation algorithms (Shivaraj, Eric, Noah)

Noah has found bugs in the Rayleigh wave recovery code, and has conducted a series of tests: https://support.physics.umn.edu/svn/ligo/radiometer/doc/Rwavetests/Modified%20Tests2/