2011 SuperDARN Workshop
FPGA-based cable length phase calibration
B. Bienvenu, N.V. Vu, E. Custovic, J. Whittington, D. Elton, J. Devlin
Department of Electronic Engineering, La Trobe University, Victoria, Australia
abstract. With the new FPGA-based transceivers for TIGER-3, we have the ability to perform a wider range of operations than previously available. One of these is digital compensation for variations in cable length, which can be adjusted at any time after installation, making possible a nominal phase precision of better than one degree TIGER 3 utilises ? inch solid feeder coax, which has a nominal loss of 0.67dB/100m. Typically, SuperDARN RADARs have used matched length cabling, meaning that cables for antennas closest to the equipment hut can be up to 100m longer than required.
This feature enables cable lengths to be set to a physical minimum, decreasing cabling costs, and an increasing both transmit and receive power ? with the only downside being a 0.1 or less of beam spreading.