prompt1PortSOL Prompts the user to measure SOL parameters at chosen port (tx) Gm = prompt1PortSOL(vnakit,settings,ports,tx) input: vnakit: (the board) object, settings: vnakit settings object, ports: mapping dictionary, possible keys: ['Tx1','Tx2','Rx1A','Rx1B','Rx2A','Rx2B'] possible values: [1, 2, 3, 4, 5, 6] tx: port number of transmitter output: Gm: [num_pts,3] measured reflection coefficients array in order of OSL