The data in the plot was the result of feeding an RF pulse directly into the digital receiver card delayed by 1800 microseconds. Here the digital receiver driver code was modified such that the delay through the driver was shorter by 6 samples. This made data from range gate 2 appear in range gate 7. As seen in the plot, tauscan data is seen in range gate 7; however, data for the same receiver driver software is seen in range gate 2.

After examining the code for several hours, it was determined that the acfcalculate function was not receiving the proper value of delay. A bit of trial and error was used and eventually the delay was set to the proper value. There is still a bit more to understand about how the delays are calculated and set throughout the software and in particular the differences in delays between the acfcalculate and acfexcalulate functions.

With the remaining time in the day, the custom filter was installed in the Receiver Phasing Unit after all of the 16 RF signals have been combined together. This custom filter is a 10 MHz wide filter centered around 55 MHz and very steep drop off to reject out of band signals. As well, the receiver front end was modified so that the signals coming out of this 55 MHz filter are amplified by ~40 dB and mixed with a signal that is equal to 71 MHz minus the 1st LO frequency resulting in a desired frequency of 71 MHz. This signal is then filtered by the 71 MHz SAW filter and amplified again by ~40 dB. Creating the '71 MHz minus the 1st LO' frequency also involved some modifications to the receiver front end in order to create this signal.

After these modifications, the radar was restarted in tauscan at around 0110 UTC on Nov. 30 and appeared to be collecting sensible data.

A fun side note about this trip, we learned that the farm managers at Blackstone are looking to let cattle graze amongst the antenna array. Hopefully the cattle don't become too interested in our coax cable; we discussed some options with the farm managers about protecting our antenna array from any curious cows.