What was found
CALLED DISPATCH VIA SATCOM. AFTER CONNECTED ABLE TO HEAR/RECEIVE DISPATCH BUT THEY COULD NOT HEAR US. TRIED MULTIPLE TIMES TRANSMITTING ON HF 1. ALSO CONNECTED VIA SATCOM 2. TRANSMITTING HF 2 BUT DISPATCH COULD NOT HEAR US. BOTH HF/SAT XFER SWITCHES SELECTED TO SAT. GROUNDED - YES. PERFORMED HF COMMUNICATION SYSTEM TEST FOR HF#1 AND HF #2 IAW B737-900 AMM 23-11-00. NO FAULTS FOUND, COMMUNICATION TO AND FROM CLEAR ON BOTH HF 1 AND HF 2. HF SYSTEM TEST FOR #1 AND #2 SYSTEM GOOD. PERFORMED SATCOM COMMUNICATION TEST IAW AMM 23-15-00. NO DEFECTS FOUND, SAT COM 1 AND SAT COM 2 PROVIDED CLEAR TRANSMISSION TO AND FROM.