Add info for set_ant

doc/man1/rigctl.1

@@ -671,15 +671,15 @@ Number is 1-based antenna# (\(oq1\(cq, \(oq2\(cq, \(oq3\(cq, ...).
 .IP
 Option depends on rig..for Icom it probably sets the Tx & Rx antennas as in the IC-7851. See your manual for rig specific option values. Most rigs don't care about the option.
 .IP
-For the IC-7851 (and perhaps others) it means this:
+For the IC-7851, FTDX3000 (and perhaps others) it means this:
 .IP
 .in +4n
 .EX
 1 = TX/RX = ANT1
 2 = TX/RX = ANT2
 3 = TX/RX = ANT3
-4 = TX/RX = ANT1/ANT4
-5 = TX/RX = ANT2/ANT4
+4 = TX/RX = ANT1/ANT4 or ANT1/ANT3
+5 = TX/RX = ANT2/ANT4 or ANT2/ANT3
 6 = TX/RX = ANT3/ANT4
 .EE
 .in