Field Report: Lettau AWS

Date: 30/Jan/2010

Time: 1:30 pm local - Ground time of less than an hour

Team Members:  Matthew Lazzara, Lee Welhouse, Lexy and Lee (Twin Otter pilots)

Measurements to the surface (bottom of the following):

Boom (to I-beam):   90.00 inches (2.29 meters)
Solar Panel:        66.25 inches (1.68 meters)
Junction Box:       27.00 inches (0.69 meters)
Electronics Box:    41.50 inches (1.05 meters)
Delta-T:            11.50 inches (0.29 meters)

Battery Voltages:

Solar Panel:           14.0 volts
Battery (yellow cord): 12.7 volts -Replaced with new box...
Battery (black cord):  13.3 volts
Junction Box:          12.9 volts

UNAVCO GPS:  Yes

Work Description:

The primary visit was to replace batteries.  While the voltage measurements seemed good, we did replace the battery box with the lower voltage. The removed battery box was retro'ed. The only thing we can think of that might impact the battery performance was that it wasn't buried all of the way.  This time, we did get it below the surface.  While the choice to leave the deeper battery in may not have been the right choice, we felt it was working well with a higher voltage.

In addition to the battery, we did change the way the solar panel was mounted - it was mounted with both mounts on the top and none on the bottom - so we move one mount from the top to the bottom - so it held on better (a really strong wind would bend the panel the way it was mounted.

Otherwise, the visit was wonderful - much nicer weather than in McMurdo/Pegasus - sunny, dead calm (-5 C).  It was hard to leave.

Two transmissions were received upon arriving with the telonics, and two transmissions were received before departing with the telonics (after the work was completed).

This station is the last station in Antarctica that has the older tower type on it, and will need a raise next visit & switch to a new tower type.