Homestake Telecon Minutes, 10/31/13
Attending: Vuk, Eric, Nelson, Gary, Patrick, Tanner, Michael, Gabor S
1) Status at Homestake (Vuk, Victor, Tanner) Vuk: still waiting to hear back from Homestake about cost estimates, expect to hear very soon. Once we hear from them, and finalize the locations of underground stations, will have to interact with SURF to find appropriate locations for surface stations too.
Gary: can wait until summer, when the weather is better. If you have a permission from the owners, could build a station in a day. Use standard PASSCAL setup with solar pannel. Data retreival could be done with the line-of-sight - best to put up antenna and use radios that PASSCAL has to transmit to the main building. Would need a cable from the receiver to the computer in the building. Could also use cell modem, but have to pay the cell bill, of about $30/month/station. Antenna is better, Gary has much experience with it. Should look at the land ownership and check that there are no objections.
2) PASSCAL communications (Vuk, Gary)
a) availability of instruments b) timing/synchronization
Vuk: Received information about two digitizer systems: Q330 and Reftek-130.
Q330: appears there are multiple solutions that should work with optical fibers, still trying to understand the details. Reftek: need a GPS extender (which converts the signal from GPS antenna to appropriate format), 5 twisted-pair cables, and repeaters.
It looks like there are commercially available products that take the GPS signal from the antenna, convert it into light signal that are then sent down the optical fiber. It seems also possible to daisy chain many receivers to this fiber. Have to inquire…
Vuk: the Reftek option seems problematic, since we would have to run the dedicated 5-twisted-pair-cable down the shaft and along the drifts. SURF already has fibers in place down the shaft, and in many drifts. Gary: agrees that Reftek is harder because of the cable. The communication with Reftek-130 is problematic, it functions but not very well. Currently running 60 of them, there are a lot of problems. Q330 is probably better.
3) UMN test setup (Tanner) Tanner: hoping to finish the setup today. Received all parts, put together a box to convert the signal from D-connector to BNC connectors, and 2 pins for mass centering. Need to finish an adapter for power supply, after which will talk to Shivaraj about software, DAQ etc. Will start testing then.
4) Analysis of existing data
a) Frames/miniSEED files (Shivaraj, Tanner, Michael)
Shivaraj (offline): I have fixed the problems with the frame generation code and now generating the frames.
b) Wiener filtering (Michael, Jan)
Michael (after the main call ended): looking at the trends in filter coefficients. Ran into the problem - the filter depends on how the data is bandpassed. Filter coefficients above the bandpassing are noisy, probably meaningless to even plot them. But in the frequencies that we care for, we don't see any particular trends. Waiting for Jan, maybe will have other ideas. Vuk: Could also try generating the coefficients on shorter time-scale, every few minutes or so. For frequencies around 1 Hz or higher, this could be the time scale over which the sources change.
c) Estimation algorithms (Shivaraj)
Shivaraj (offline): I haven't spend much time on the simulation code yet. The one thing remaining is combining different wave components in the recovery matrix. I will try that this weekend (the changes are simple, but the code is crashing due to memory requirement. So have to find way to avoid it).
Vuk: should check if this code has been placed in the repository?
5) New wiki (Vuk) Vuk: Ready now, should be informing everyone soon of their login information.