Merge pull request #718 from anarkiwi/nanit

Better overlap defaults, fix fft.png presentation for non-linear scans, add note for Ettus workaround.

README.md

@@ -171,6 +171,10 @@ Ettus SDRs download firmware and switch USB identities when first powered up. Re
 
 UHD driver arguments ```num_recv_frames``` or ```recv_frame_size``` may be too high. The defaults are defined as ETTUS_ARGS in [utils.py](gamutrf/utils.py). Try reducing one or both via ```--sdrargs```. For example, ```--sdrargs num_recv_frames=64,recv_frame_size=8200,type=b200```.
 
+#### Scanner with Ettus SDR shows implausible low power at approx 100MHz intervals
+
+Ettus radios may need extra time to produce good data when being retuned rapidly by the scanner. Try adding ```--skip-tune-step=1024``` to the scanner command line and increase the value until the power dips disappear. This parameter will slow down the scan speed.
+
 #### "O"s or warnings about overflows in SDR containers
 
 * Ensure your hardware can support the I/Q sample rate you have configured (gamutRF has been tested on Pi4 at 20Msps, which is the default recording rate). Also ensure your recording medium (e.g. flash drive, USB hard disk) is not timing out or blocking.

gamutrf/scan.py

@@ -163,14 +163,14 @@ def argument_parser():
         "--tuneoverlap",
         dest="tuneoverlap",
         type=float,
-        default=0.5,
+        default=0.85,
         help="multiple of samp_rate when retuning",
     )
     parser.add_argument(
         "--bucket_range",
         dest="bucket_range",
         type=float,
-        default=1.0,
+        default=0.85,
         help="what proportion of FFT buckets to use",
     )
     parser.add_argument(

gamutrf/sigfinder.py

@@ -212,6 +212,10 @@ def process_scan(args, scan_configs, prom_vars, df, lastbins, running_df, last_d
                 threshold=args.threshold,
             )
         )
+    min_samp_rate = (
+        min([scan_config["sample_rate"] for scan_config in scan_configs]) / 1e6
+    )
+    df.loc[freqdiffs > min_samp_rate * 2, "db"] = np.nan
 
     if PEAK_TRIGGER == 1 and signals:
         led_sleep = 0.2

gamutrf/zmqreceiver.py

@@ -147,9 +147,10 @@ def txtbuf_to_lines(self, log):
             return lines
         return None
 
-    def read_new_frame_df(self, df):
+    def read_new_frame_df(self, df, discard_time):
         frame_df = None
-        df = df[(time.time() - df.ts).abs() < 60]
+        if discard_time:
+            df = df[(time.time() - df.ts).abs() < discard_time]
         if df.size:
             lastfreq = df.freq.iat[-1]
             logging.info("last frequency read %f MHz", lastfreq / 1e6)
@@ -196,14 +197,14 @@ def lines_to_df(self, lines):
             logging.error(str(err))
             return (None, None)
 
-    def read_buff(self, log):
+    def read_buff(self, log, discard_time):
         scan_config = None
         frame_df = None
         if self.read_buff_file():
             lines = self.txtbuf_to_lines(log)
             if lines:
                 scan_config, df = self.lines_to_df(lines)
-                frame_df = self.read_new_frame_df(df)
+                frame_df = self.read_new_frame_df(df, discard_time)
         return scan_config, frame_df
 
 
@@ -254,8 +255,8 @@ def frame_resample(self, df):
             return df.sort_values("freq")
         return df
 
-    def read_buff(self, log=None):
-        results = [scanner.read_buff(log) for scanner in self.scanners]
+    def read_buff(self, log=None, discard_time=0):
+        results = [scanner.read_buff(log, discard_time) for scanner in self.scanners]
         if self.last_results:
             for i, result in enumerate(results):
                 _scan_config, df = result

tests/test_sigfinder.py

@@ -183,6 +183,7 @@ def test_process_scans(self):
                 scan_config = {
                     "freq_start": freq_start,
                     "freq_end": freq_end,
+                    "sample_rate": int(1e6),
                 }
                 with open(zmqr.scanners[0].buff_file, "wb") as zbf:
                     with context.stream_writer(zbf) as bf:
@@ -193,6 +194,7 @@ def test_process_scans(self):
                                 "config": {
                                     "freq_start": freq_start,
                                     "freq_end": freq_end,
+                                    "sample_rate": int(1e6),
                                 },
                                 "buckets": {},
                             }