diff --git a/impl/src/layer1/correlator.c b/impl/src/layer1/correlator.c
index f94e521..5db3df2 100644
--- a/impl/src/layer1/correlator.c
+++ b/impl/src/layer1/correlator.c
@@ -143,7 +143,6 @@ float correlator_get_mean_frequency_deviation(correlator_ctx_t *ctx, size_t L, f
 	for(size_t m = m0; m < ctx->search_sequence_len; m++) {
 		size_t nm = (n + m) & ctx->buffer_size_mask;
 		z[m - m0] = ctx->search_sequence[m] * ctx->input_history[nm];
-		printf("%+.6f%+.6fj  -  %+.6f%+.6fj\n", crealf(ctx->search_sequence[m]), cimagf(ctx->search_sequence[m]), crealf(ctx->input_history[nm]), cimagf(ctx->input_history[nm]));
 	}
 
 	/* Louise & Regiannini frequency estimator */
diff --git a/impl/src/layer1/rx.c b/impl/src/layer1/rx.c
index 1a17bbf..fc187ec 100644
--- a/impl/src/layer1/rx.c
+++ b/impl/src/layer1/rx.c
@@ -12,6 +12,14 @@
 #define HEADER_SIZE_BYTES 4
 #define FREQ_EST_L 8
 
+#define SHOW_DEBUG_LOG 0
+
+#if SHOW_DEBUG_LOG
+#	define DEBUG_LOG(...) fprintf(stderr, __VA_ARGS__)
+#else
+#	define DEBUG_LOG(...) {}
+#endif
+
 static void update_nco_pll(nco_crcf nco, float phase_error)
 {
 	static const float pll_alpha = 0.05f;                          // phase adjustment factor
@@ -32,29 +40,29 @@ static bool acquire_preamble(layer1_rx_t *rx, const float complex sample)
 
 	if(cabsf(corr_out) > 0.5f * preamble_get_symbol_count()) {
 		// Preamble found!
-		printf("Preamble found: %.3f > %.3f\n", cabsf(corr_out), 0.5f * preamble_get_symbol_count());
+		DEBUG_LOG("Preamble found: %.3f > %.3f\n", cabsf(corr_out), 0.5f * preamble_get_symbol_count());
 
 		float phase_offset;
 		float mean_frequency_error = correlator_get_mean_frequency_deviation(&rx->preamble_correlator, FREQ_EST_L, &phase_offset);
 
-		printf("Phase offset:                 %.6f rad\n", phase_offset);
-		printf("Preamble frequency deviation: %.6f rad/symbol\n", mean_frequency_error);
+		DEBUG_LOG("Phase offset:                 %.6f rad\n", phase_offset);
+		DEBUG_LOG("Preamble frequency deviation: %.6f rad/symbol\n", mean_frequency_error);
 
 		// Set the fine carrier correction NCO to the values estimated from the preamble
 		nco_crcf_set_frequency(rx->carrier_fine_nco, mean_frequency_error / RRC_SPS * 0.5f);
 		nco_crcf_set_phase(rx->carrier_fine_nco, phase_offset);
 
-		printf("New estimated carrier frequency: %.6f + %.6f\n", nco_crcf_get_frequency(rx->carrier_coarse_nco), nco_crcf_get_frequency(rx->carrier_fine_nco));
+		DEBUG_LOG("New estimated carrier frequency: %.6f + %.6f\n", nco_crcf_get_frequency(rx->carrier_coarse_nco), nco_crcf_get_frequency(rx->carrier_fine_nco));
 
 		//float complex input_history[preamble_get_symbol_count()];
 		//correlator_get_input_history(&rx->preamble_correlator, input_history);
 
-		//printf("import numpy as np\n");
-		//printf("import matplotlib.pyplot as pp\n");
+		//DEBUG_LOG("import numpy as np\n");
+		//DEBUG_LOG("import matplotlib.pyplot as pp\n");
 		//print_complex_array("pre", preamble_get_symbols(), preamble_get_symbol_count());
 		//print_complex_array("recv", input_history, preamble_get_symbol_count());
-		//printf("pp.plot(np.angle(recv * pre.conj()))\n");
-		//printf("pp.show()\n");
+		//DEBUG_LOG("pp.plot(np.angle(recv * pre.conj()))\n");
+		//DEBUG_LOG("pp.show()\n");
 
 		// start over with frequency estimation when preamble search restarts.
 		freq_est_history_write_idx = 0;
@@ -71,7 +79,7 @@ static bool acquire_preamble(layer1_rx_t *rx, const float complex sample)
 			float freq_adjustment = (freq_est / RRC_SPS) * 0.3f;
 			nco_crcf_adjust_frequency(rx->carrier_coarse_nco, freq_adjustment);
 
-			printf("Frequency adjustment: %.6f - carrier frequency: %.6f\n", freq_adjustment, nco_crcf_get_frequency(rx->carrier_coarse_nco));
+			DEBUG_LOG("Frequency adjustment: %.6f - carrier frequency: %.6f\n", freq_adjustment, nco_crcf_get_frequency(rx->carrier_coarse_nco));
 
 			freq_est_history_write_idx = 0;
 		}
@@ -123,7 +131,7 @@ result_t layer1_rx_process(layer1_rx_t *rx, const float complex *samples, size_t
 						modem_demodulate(rx->hdr_demod, mixed_sample, &sym_demod);
 
 						float phase_error = modem_get_demodulator_phase_error(rx->hdr_demod);
-						printf("Sym: %d; Phase error: %f\n", sym_demod, phase_error);
+						DEBUG_LOG("Sym: %d; Phase error: %f\n", sym_demod, phase_error);
 
 						update_nco_pll(rx->carrier_fine_nco, phase_error);
 
@@ -150,10 +158,10 @@ result_t layer1_rx_process(layer1_rx_t *rx, const float complex *samples, size_t
 						rx->payload_len_enc_bytes = fec_get_enc_msg_length(PAYLOAD_CHANNEL_CODE, rx->payload_len_bytes);
 						rx->payload_len_symbols = (rx->payload_len_enc_bytes * 8 + payload_bps - 1) / payload_bps;
 
-						printf("=== DECODED HEADER ===\n");
-						printf("Payload length: %u symbols, %u bytes encoded, %u bytes decoded\n", rx->payload_len_symbols, rx->payload_len_enc_bytes, rx->payload_len_bytes);
-						printf("CRC16: 0x%04x\n", rx->payload_crc);
-						printf("======================\n");
+						DEBUG_LOG("=== DECODED HEADER ===\n");
+						DEBUG_LOG("Payload length: %u symbols, %u bytes encoded, %u bytes decoded\n", rx->payload_len_symbols, rx->payload_len_enc_bytes, rx->payload_len_bytes);
+						DEBUG_LOG("CRC16: 0x%04x\n", rx->payload_crc);
+						DEBUG_LOG("======================\n");
 
 						//dump_array_cf(symbols_cpx, symbol_counter, 1.0f, "/tmp/hdr.cpx");
 
@@ -169,7 +177,7 @@ result_t layer1_rx_process(layer1_rx_t *rx, const float complex *samples, size_t
 						modem_demodulate(rx->payload_demod, mixed_sample, &sym_demod);
 
 						float phase_error = modem_get_demodulator_phase_error(rx->payload_demod);
-						printf("Sym: %d; Phase error: %f\n", sym_demod, phase_error);
+						DEBUG_LOG("Sym: %d; Phase error: %f\n", sym_demod, phase_error);
 
 						update_nco_pll(rx->carrier_fine_nco, phase_error);
 
diff --git a/impl/src/layer1/tx.c b/impl/src/layer1/tx.c
index 0a4f2d0..57a6667 100644
--- a/impl/src/layer1/tx.c
+++ b/impl/src/layer1/tx.c
@@ -83,7 +83,7 @@ result_t layer1_tx_add_packet_to_burst(layer1_tx_t *tx, const uint8_t *data, siz
 		result_t res = transmission_ramp_up(&tx->transmission, get_write_ptr(tx), &len);
 
 		if(res != OK) {
-			printf("Ramp-up requires %zd samples at offset %zd.\n", len, tx->samples_used);
+			fprintf(stderr, "Ramp-up requires %zd samples at offset %zd.\n", len, tx->samples_used);
 			return res;
 		}
 
@@ -120,7 +120,7 @@ result_t layer1_tx_add_packet_to_burst(layer1_tx_t *tx, const uint8_t *data, siz
 	result_t res = transmission_filter_packet(&tx->transmission, msg_mod, nsyms, get_write_ptr(tx), &len);
 
 	if(res != OK) {
-		printf("Packet requires %zd samples at offset %zd.\n", len, tx->samples_used);
+		fprintf(stderr, "Packet requires %zd samples at offset %zd.\n", len, tx->samples_used);
 		return res;
 	}
 
@@ -147,7 +147,7 @@ result_t layer1_tx_finalize_burst(layer1_tx_t *tx)
 	result_t res = transmission_ramp_down(&tx->transmission, get_write_ptr(tx), &len);
 
 	if(res != OK) {
-		printf("Ramp-down requires %zd samples at offset %zd.\n", len, tx->samples_used);
+		fprintf(stderr, "Ramp-down requires %zd samples at offset %zd.\n", len, tx->samples_used);
 		return res;
 	}
 
diff --git a/impl/src/main.c b/impl/src/main.c
index ee109c9..764b7e8 100644
--- a/impl/src/main.c
+++ b/impl/src/main.c
@@ -11,18 +11,18 @@
 #define RESULT_CHECK(stmt) { \
 	result_t res = stmt; \
 	if(res != OK) { \
-		printf("Error %d in %s:%d!", res, __FILE__, __LINE__); \
+		fprintf(stderr, "Error %d in %s:%d!", res, __FILE__, __LINE__); \
 		exit(1); \
 	} \
 }
 
 void print_complex_array(const char *varname, float complex const *array, size_t len)
 {
-	printf("%s=np.array([%f%+fj", varname, crealf(array[0]), cimagf(array[0]));
+	fprintf(stderr, "%s=np.array([%f%+fj", varname, crealf(array[0]), cimagf(array[0]));
 	for(size_t k = 1; k < len; k++) {
-		printf(", %f%+fj", crealf(array[k]), cimagf(array[k]));
+		fprintf(stderr, ", %f%+fj", crealf(array[k]), cimagf(array[k]));
 	}
-	printf("])\n");
+	fprintf(stderr, "])\n");
 }
 
 
@@ -31,17 +31,17 @@ void cb_rx(rx_evt_t evt, uint8_t *packet_data, size_t packet_len)
 	switch(evt)
 	{
 		case RX_EVT_CHECKSUM_ERROR:
-			printf("Received a message of %zu bytes, but decoding failed.\n", packet_len);
+			fprintf(stderr, "Received a message of %zu bytes, but decoding failed.\n", packet_len);
 			break;
 
 		case RX_EVT_PACKET_RECEIVED:
-			printf("=== DECODED PAYLOAD ===\n");
-			printf("%s\n", packet_data);
-			printf("=======================\n");
+			fprintf(stderr, "=== DECODED PAYLOAD ===\n");
+			fprintf(stderr, "%s\n", packet_data);
+			fprintf(stderr, "=======================\n");
 			break;
 
 		case RX_EVT_PREAMBLE_FOUND:
-			printf("Found preamble!");
+			fprintf(stderr, "Found preamble!\n");
 			break;
 	}
 }
@@ -95,5 +95,5 @@ int main(void)
 	layer1_tx_shutdown(&tx);
 	layer1_rx_shutdown(&rx);
 
-	printf("Done.\n");
+	fprintf(stderr, "Done.\n");
 }