some quick nudges to allow reconfiguration of the rtl_sdr command on the fly

owrx/controllers.py

@@ -72,6 +72,7 @@ class WebSocketMessageHandler(object):
     def __init__(self):
         self.handshake = None
         self.client = None
+        self.dsp = None
 
     def handleTextMessage(self, conn, message):
         pm = PropertyManager.getSharedInstance()

owrx/source.py

@@ -126,11 +126,12 @@ class SpectrumThread(threading.Thread):
         while self.doRun:
             data=dsp.read(bytes_to_read)
             if len(data) == 0:
-                self.shutdown()
+                time.sleep(1)
             else:
                 for c in self.clients:
                     c.write_spectrum_data(data)
 
+        dsp.stop()
         print("spectrum thread shut down")
 
     def add_client(self, c):