Through several methods of measurement, then scrutinizing the measurement, then rethinking just about everything we thought we knew, the interferometer cables were cut to the same electrical length. These cable are made of LMR-600 type coax and are the several hundred feet long cables that connection the antenna feeds to the electronics inside of the building. I often refer to these as 'ground coax' since most of the coax is buried underground.

Two methods were used to measure the length of the ground coax cables during this trip. One method sent a constant signal out along the cable through a 180 degree splitter/combiner and directional coupler. The directional coupler picked up the return signal from the open end of the cable. The 180 degree combiner was used to find the point at which the forward signal with the return signal were 180 degrees out of phase. This frequency point, along with another frequency point can be used to calculate the electrical length of the cable. However, the precision needed for phasing the cables could not be achieved.

Another method to measure this length was to use the newly acquired network analyzer. However, one type of measurement seemed straight forward, but then was questioned when a simple adjustment to the number of data points drastically changed our readings. The network analyzer could use the same theory as the previously mentioned method BUT the network analyzer could achieve a precision much greater than the previous method.

In the end, all of the cables for the interferometer were phased within a few centimeters of electrical length. Connectors were crimped down as a final say that the cables were all a match. From here the ground coax cables will be connected to a receiver front end and FINALLY Wallops will begin collecting interferometer data.

In addition to this work, several parts and boards needed to do repairs on the Wallops-style transmitter currently in the Blacksburg lab were taken from the Wallops site. These parts had tape and other markings indicating that repairs may need to be made before the transmitter will function. On the antenna array side of things, there were a few reflector wires down on both the main array and the interferometer array. The main array only had 2 wires down across 1 gap horizontally; the interferometer array's top-most reflector wire is hanging down and only attached across one gap.