Clear and sunny along the coastal region all day. Clouds/fog over the Santa Ynez valley in the mornings, clearing skies and windy (20+ mph) in the afternoon.
Started the day at ISS #1. Isabell joined us today to work on networking & software issues. Bill and Liz replaced the hard drive in the Lidar, which required Bill to update the client on the lidar laptop, which Bill was able to do after some texting with tech support in Europe (before they went to bed). Lidar is now working and Bill can comment/clarify if the data is being transferred as desired to the data manager. Grabbed some RF adapters/attenuators and two towels from the trailer for debugging and cleaning the ISS #3 wind profiler antenna.
Stopped by ISS #2 after lunch to check on the systems and for Liz and Bill to work on networking/software issues. The following images show the current draw of the final amplifier and the returns being generated by the 'good' 915 MHz radar for comparison with returns with the 'bad' radar at ISS #3.
ISS2 (RFE #2) Amp Current
ISS2 WA0 X-vert ISS2 WA1 Y-vert
ISS2 WA2 X+ East ISS2 WA4 X- West
ISS2 WA3 Y+ North ISS2 WA5 Y- South
We then continued on to ISS #3. When we arrived, the profiler, its computer, and the ceilometer computer were all off. It appears that the site lost power around 4-5 am local time this morning and was off for at least long enough for the CyberPower UPS's battery to completely drain and the UPS turned off. The UPS did not power back on when line power was restored, but it did recharge its batteries. John looked at the manual and datasheet for the UPS and did not find any settings that would change the UPS's behavior. The datasheet also showed that the UPS would power everything plugged into it for ~17-20 minutes at the present load levels. We will look at moving the ceilometer computer and monitor over to the UPS that the sounding computer is plugged into, which either did not deplete its battery completely or was able to turn back on its load outlets when line power was out since the sounding system was on when we arrived. After powering everything back up, John and Liz measured AGL sensor heights while Bill and Isabell did more work on networking and software (and other things?).
On the 'bad' wind profiler front, for comparison purposes, the final amp current of the ISS3 system (RFE #1) was 3.52 Amps, comparable to the power output of the 'good' system at ISS2. Images of the returns being generated were also taken, but alas, they were accidentally deleted. John will take images tomorrow and add them here, though atmospheric conditions may not be identical. Bill has determined that the NIMA processing is able to clean up the 'bad' returns well enough that the antenna will likely not need to be replaced at this time. However, the returns used for this analysis were under windy and moderately humid conditions that produced returns strong enough so as to minimize the effects of the antenna's clutter signal. We are interested to see how the processing performs when the signal returns are weaker, i.e. drying conditions and/or lower winds, some of which we may see tomorrow. Since SWEX is primarily interested high wind conditions, potentially poorer performance under low wind conditions may not be an issue.
It was quit windy (~20 mph) at the site so it was decided to postpone removing the clutter fence and radome until tomorrow when winds are forecasted to be less than ~10 mph. Once apart, the dust/dirt layer on the antenna will be removed and the RFE modified to accept an external local oscillator (LO) frequency from the signal generator that John brought out. Antenna input return loss measurements from yesterday indicate that the antenna's performance, across all beams, can slightly be improved by lowering the operating frequency to ~912.8 MHz from its nominal 915 MHz. We should have more data after tomorrow's work on the antenna's and system performace.