diff --git a/uplink/modulate_hackrf_hex.py b/uplink/modulate_hackrf_hex.py
index bdf1f6f..56c1a38 100755
--- a/uplink/modulate_hackrf_hex.py
+++ b/uplink/modulate_hackrf_hex.py
@@ -37,6 +37,8 @@
 	baseband = baseband + [1 if phase else -1]
 	phase = phase if bit == "1" else not phase
 
+baseband.extend([0] * int(0.5 * BAUDRATE))
+
 # write complete signal to hackrf RAW I/Q file:
 # * Repeat bits int(SAMPLERATE / BAUDRATE) times to achieve sample rate
 # * Hack: Set I and Q to always be the same value by multiplying by "2"
diff --git a/uplink/modulate_hackrf_hex_multiplex.py b/uplink/modulate_hackrf_hex_multiplex.py
index 0ed4479..bf7214e 100755
--- a/uplink/modulate_hackrf_hex_multiplex.py
+++ b/uplink/modulate_hackrf_hex_multiplex.py
@@ -12,7 +12,7 @@
 
 SAMPLERATE = 2000000
 BAUDRATE = 100
-MPX_FREQ_OFFSET = 10000
+MPX_FREQ_OFFSET = 50000
 
 OUTFILE = "/tmp/hackrf_transmission_REPLACE.raw"
 
@@ -57,6 +57,8 @@
 		# differential modulation: 180° phase shift if "1"
 		phase = phase if binstring[bit] == "1" else -phase
 
+np.append(baseband, np.zeros(int(0.5 * BAUDRATE)))
+
 # write complete signal to hackrf RAW I/Q file
 print("Quantizing...")
 iqsignal = np.int8(np.real(baseband) * 127)