diff --git a/transmit.py b/transmit.py
index d80c871e..5aa436a5 100644
--- a/transmit.py
+++ b/transmit.py
@@ -570,13 +570,23 @@ def update_doppler(fm="yes"):
 		print(f"New TX Frequency: {tx_frequency}, new RX Frequency: {rx_frequency}")
 
 		if rigctl:
-			if (tx_frequency < 148000000):
-				if (tx_frequency > 145880000):
-					tx_center = 145960000 # AO-91
-					rx_center = 435250000 # AO-73 is same tx_center but 435140000
-				else:
-					tx_center = 145800000 # ISS U/V Repeater
-					rx_center = 437800000 			
+			if (tx_frequency > 145955000) and (tx_frequency <= 145965000):
+				tx_center = 145960000 # AO-91
+				rx_center = 435250000 
+			elif (tx_frequency > 145965000) and (tx_frequency < 145975000):
+				tx_center = 145970000 # AO-73 center is shifted up 10kHz to avoid overlap with AO-91
+				rx_center = 435150000 
+			elif (tx_frequency > 145795000) and (tx_frequency < 145805000):	
+				tx_center = 145800000 # ISS U/V Repeater
+				rx_center = 437800000 
+			elif (tx_frequency > 145945000) and (tx_frequency <= 145955000):	
+				tx_center = 145950000 # AO-7
+				rx_center = 432150000 	
+			else:
+				tx_center = tx_frequency
+				rx_center = 435000000 # default RX requency	
+
+			if (rx_center != 435000000):	# don't Doppler shift default RX frequency since don't know the shift 
 				tx_doppler_shift = tx_frequency - tx_center
 				rx_doppler_shift = -1 * (rx_center/tx_center) * tx_doppler_shift
 				new_tx_frequency = tx_frequency