Overcast, occasionally rainy, some big gusts in the afternoon associated with thunderstorms

On site: Gary, Justin, Steve.  Matt and Delia arrived in the evening – welcome!!

Started the morning going through yesterday's punch list:

• swapped batteries at t44, found an issue with solar panel cabling that we fixed.  Assembled the charging system to recharge the old t44 batteries.
• checked t41 power, but everything seemed okay.  Its voltages and currents haven't changed.
• Lowered tt from about 10:15-11:30.  Pirga was set to external barometer, but the PTB110 was reading 500mb flat.  Changed the EC100 to use the "internal barometer" and now all is good.

This got us to a status of everything working!

Spent the rest of the time working on options for t50/tt.  The options appear to be:

• Build another tower near tt and move t0 sensors to it.  The local surface is rougher, so the profile won't represent the horizontal array.  Possibly reinstrument the old t0 with 2D sonics.
• Move tt to a location to the NNE of t49.  The surface and topography are essentially the same as for t0.  We should do something (black paint/wrap in foam?) to the lower section of tt to avoid generating specular reflections if REAL scans it.  We need to check with Mark if this is acceptable to air traffic, but he had left for the day by the time we checked.  We'll talk with him tomorrow.
• In the case that we move tt, we might move the t0 sensors to t49 to be closer to tt.  Chenning is pretty insistent that we should build another tower (t50) close to the new tt location, but that would require an extra sonic and I don't see how a change of 110m would make any difference.  Chenning has agreed (I think) that we could look at the profile data after the tt move to see if a t0 move is needed.

I appreciated Will's comments that pointed us to the 2 spare base plates, among other things.  I also tried plotting profiles (just wind speed so far) for only southerly winds and confirmed that profile differences are not just due to a sampling of poor wind directions.  We have a persistent problem even for the best wind directions, unfortunately.

With the disposition of t0 still unknown, it didn't make sense to work on the hot-film set-up.

So, some issues still in the air, but hopefully we'll have a resolution tomorrow....