diff --git a/impl/src/main.c b/impl/src/main.c
index a2d31cd..088a530 100644
--- a/impl/src/main.c
+++ b/impl/src/main.c
@@ -179,6 +179,8 @@ int main(int argc, char **argv)
 
 	bool on_air = true;
 
+	srand((int)(get_hires_time() * 1e6));
+
 	// ** Initialize **
 
 	char devname[IFNAMSIZ] = "hamnet70";
@@ -296,8 +298,6 @@ int main(int argc, char **argv)
 				// ensure that the buffer is full before TX is turned on to avoid transmitting empty buffers
 				RESULT_CHECK(transmit(&sdr, whole_burst, burst_len));
 
-				retransmit_time = get_hires_time() + 4.0;
-
 				if(!on_air) {
 					LOG(LVL_INFO, "RX -> TX");
 					RESULT_CHECK(sdr_stop_rx(&sdr));
@@ -318,6 +318,8 @@ int main(int argc, char **argv)
 				RESULT_CHECK(sdr_start_rx(&sdr));
 				on_air = false;
 
+				retransmit_time = get_hires_time() + 1.0 + 1.0 * rand() / RAND_MAX;
+
 				block_tx_for(TX_SWITCH_BACKOFF_AFTER_RX_ON);
 			}
 		}