Use a wider FM bandwidth when scanning/decoding at 1680 MHz.

auto_rx/autorx/decode.py

@@ -236,10 +236,19 @@ class SondeDecoder(object):
             else:
                 _rs92_gps_data = "-e %s" % self.rs92_ephemeris
 
+            # Adjust the receive bandwidth based on the band the scanning is occuring in.
+            if self.sonde_freq < 1000e6:
+                # 400-406 MHz sondes - use a 12 kHz FM demod bandwidth.
+                _rx_bw = 12000
+            else:
+                # 1680 MHz sondes - use a 28 kHz FM demod bandwidth.
+                # NOTE: This is a first-pass of this bandwidth, and may need to be optimized.
+                _rx_bw = 28000
+
             # Now construct the decoder command.
             # rtl_fm -p 0 -g 26.0 -M fm -F9 -s 12k -f 400500000 | sox -t raw -r 12k -e s -b 16 -c 1 - -r 48000 -b 8 -t wav - highpass 20 lowpass 2500 2>/dev/null | ./rs92ecc -vx -v --crc --ecc --vel -e ephemeris.dat
-            decode_cmd = "%s %s-p %d -d %s %s-M fm -F9 -s 12k -f %d 2>/dev/null |" % (self.sdr_fm, bias_option, int(self.ppm), str(self.device_idx), gain_param, self.sonde_freq)
-            decode_cmd += "sox -t raw -r 12k -e s -b 16 -c 1 - -r 48000 -b 8 -t wav - lowpass 2500 highpass 20 2>/dev/null |"
+            decode_cmd = "%s %s-p %d -d %s %s-M fm -F9 -s %d -f %d 2>/dev/null |" % (self.sdr_fm, bias_option, int(self.ppm), str(self.device_idx), gain_param, _rx_bw, self.sonde_freq)
+            decode_cmd += "sox -t raw -r %d -e s -b 16 -c 1 - -r 48000 -b 8 -t wav - lowpass 2500 highpass 20 2>/dev/null |" % _rx_bw
             decode_cmd += "./rs92ecc -vx -v --crc --ecc --vel --json %s 2>/dev/null" % _rs92_gps_data
 
         elif self.sonde_type == "DFM":

auto_rx/autorx/scan.py

@@ -191,15 +191,23 @@ def detect_sonde(frequency, rs_path="./", dwell_time=10, sdr_fm='rtl_fm', device
     else:
         gain_param = ''
 
+    # Adjust the detection bandwidth based on the band the scanning is occuring in.
+    if frequency < 1000e6:
+        # 400-406 MHz sondes - use a 22 kHz detection bandwidth.
+        _rx_bw = 22000
+    else:
+        # 1680 MHz sondes - use a 28 kHz detection bandwidth.
+        # NOTE: This is an initial stab in the dark at a setting for this band.
+        _rx_bw = 28000
+
     # Sample Source (rtl_fm)
-    rx_test_command = "timeout %ds %s %s-p %d -d %s %s-M fm -F9 -s 22k -f %d 2>/dev/null |" % (dwell_time, sdr_fm, bias_option, int(ppm), str(device_idx), gain_param, frequency) 
+    rx_test_command = "timeout %ds %s %s-p %d -d %s %s-M fm -F9 -s %d -f %d 2>/dev/null |" % (dwell_time, sdr_fm, bias_option, int(ppm), str(device_idx), gain_param, _rx_bw, frequency) 
     # Sample filtering
-    rx_test_command += "sox -t raw -r 22k -e s -b 16 -c 1 - -r 48000 -t wav - highpass 20 2>/dev/null |"
+    rx_test_command += "sox -t raw -r %d -e s -b 16 -c 1 - -r 48000 -t wav - highpass 20 2>/dev/null |" % _rx_bw
     # Sample decoding / detection
     rx_test_command += os.path.join(rs_path,"dft_detect") + " 2>/dev/null"
 
-    #print(rx_test_command)
-
+    logging.debug("Scanner #%s - Using detection command: %s" % (str(device_idx), rx_test_command))
     logging.debug("Scanner #%s - Attempting sonde detection on %.3f MHz" % (str(device_idx), frequency/1e6))
 
     try:

auto_rx/test/generate_lowsnr.py

@@ -40,7 +40,8 @@ SAMPLES = [
     ['rs41_96k_float.bin', 4800, -20.0, 96000], 
     ['rs92_96k_float.bin', 2400, -100, 96000], # No threshold set, as signal is continuous.
     ['dfm09_96k_float.bin', 2500, -100, 96000], # Weird baud rate. No threshold set, as signal is continuous.
-    ['m10_96k_float.bin', 9616, -10.0, 96000]  # Really weird baud rate.
+    ['m10_96k_float.bin', 9616, -10.0, 96000],  # Really weird baud rate.
+    #['rsngp_96k_float.bin', 2400, -100.0, 96000]  # RS92-NGP - wider bandwidth.
 ]
 
 

auto_rx/test/test_demod.py

@@ -233,6 +233,37 @@ processing_type['rs92_rtlfm'] = {
 }
 
 
+# RS92-NGP (wider bandwidth)
+_fm_rate = 28000
+# Calculate the necessary conversions
+_rtlfm_oversampling = 8.0 # Viproz's hacked rtl_fm oversamples by 8x.
+_shift = -2.0*_fm_rate/_sample_fs # rtl_fm tunes 'up' by rate*2, so we need to shift the signal down by this amount.
+
+_resample = (_fm_rate*_rtlfm_oversampling)/_sample_fs
+
+if _resample != 1.0:
+    # We will need to resample.
+    _resample_command = "csdr convert_f_s16 | ./tsrc - - %.4f | csdr convert_s16_f |" % _resample
+    _shift = (-2.0*_fm_rate)/(_sample_fs*_resample)
+else:
+    _resample_command = ""
+
+_demod_command = "| %s csdr shift_addition_cc %.5f 2>/dev/null | csdr convert_f_u8 |" % (_resample_command, _shift)
+_demod_command += " ./rtl_fm_stdin -M fm -f 401000000 -F9 -s %d  2>/dev/null|" % (int(_fm_rate))
+_demod_command += " sox -t raw -r %d -e s -b 16 -c 1 - -r 48000 -b 8 -t wav - highpass 20 2>/dev/null |" % int(_fm_rate)
+
+
+processing_type['rs92ngp_rtlfm'] = {
+    'demod': _demod_command,
+    # Decode using rs92ecc
+    'decode': "../rs92ecc -vx -v --crc --ecc --vel 2>/dev/null",
+    #'decode': "../rs92ecc -vx -v --crc --ecc -r --vel 2>/dev/null", # For measuring No-ECC performance
+    # Count the number of telemetry lines.
+    "post_process" : "| grep P3213708 | wc -l",
+    #"post_process" : " | grep \"errors: 0\" | wc -l",
+    'files' : "./generated/rsngp*.bin" 
+}
+
 # DFM
 _fm_rate = 20000
 # Calculate the necessary conversions