diff --git a/apps/modes_gui b/apps/modes_gui
index d9bbbea..af4d036 100755
--- a/apps/modes_gui
+++ b/apps/modes_gui
@@ -48,8 +48,8 @@ class mainwindow(QtGui.QMainWindow):
         #should round to actual achieved gain
         self.ui.line_gain.insert("30")
 
-        #default to 3dB
-        self.ui.line_threshold.insert("3")
+        #default to 5dB
+        self.ui.line_threshold.insert("5")
 
         self.ui.prog_rssi.setMinimum(-40)
         self.ui.prog_rssi.setMaximum(0)
diff --git a/apps/modes_rx b/apps/modes_rx
index 18313d1..9eba395 100755
--- a/apps/modes_rx
+++ b/apps/modes_rx
@@ -151,7 +151,7 @@ if __name__ == '__main__':
                       help="set RF gain", metavar="dB")
   parser.add_option("-r", "--rate", type="eng_float", default=4000000,
                       help="set ADC sample rate [default=%default]")
-  parser.add_option("-T", "--threshold", type="eng_float", default=3.0,
+  parser.add_option("-T", "--threshold", type="eng_float", default=5.0,
                       help="set pulse detection threshold above noise in dB [default=%default]")
   parser.add_option("-a","--output-all", action="store_true", default=False,
                       help="output all frames")
diff --git a/lib/air_modes_preamble.cc b/lib/air_modes_preamble.cc
index 157707a..deab73b 100644
--- a/lib/air_modes_preamble.cc
+++ b/lib/air_modes_preamble.cc
@@ -45,7 +45,7 @@ air_modes_preamble::air_modes_preamble(int channel_rate, float threshold_db) :
 	d_samples_per_symbol = d_samples_per_chip * 2;
 	d_check_width = 120 * d_samples_per_symbol; //only search to this far from the end of the stream buffer
 	d_threshold_db = threshold_db;
-	d_threshold = powf(10., threshold_db/10.); //the level that the sample must be above the moving average in order to qualify as a pulse
+	d_threshold = powf(10., threshold_db/20.); //the level that the sample must be above the moving average in order to qualify as a pulse
 	d_secs_per_sample = 1.0 / channel_rate;
 	set_output_multiple(1+d_check_width*2);
 	
diff --git a/lib/air_modes_slicer.cc b/lib/air_modes_slicer.cc
index c6519aa..48ea8b0 100644
--- a/lib/air_modes_slicer.cc
+++ b/lib/air_modes_slicer.cc
@@ -65,8 +65,8 @@ static slice_result_t slicer(const float bit0, const float bit1, const float ref
 	slice_result_t result;
 
 	//3dB limits for bit slicing and confidence measurement
-	float highlimit=ref*2;
-	float lowlimit=ref*0.5;
+	float highlimit=ref*1.414;
+	float lowlimit=ref*0.707;
 	
 	bool firstchip_inref  = ((bit0 > lowlimit) && (bit0 < highlimit));
 	bool secondchip_inref = ((bit1 > lowlimit) && (bit1 < highlimit));
diff --git a/python/cpr.py b/python/cpr.py
index 5115bf5..1d647dd 100755
--- a/python/cpr.py
+++ b/python/cpr.py
@@ -172,7 +172,6 @@ def range_bearing(loc_a, loc_b):
 class cpr_decoder:
 	def __init__(self, my_location):
 		self.my_location = my_location
-		self.lkplist = {}
 		self.evenlist = {}
 		self.oddlist = {}
 
@@ -180,9 +179,9 @@ class cpr_decoder:
 		self.my_location = new_location
 
 	def weed_poslists(self):
-		for poslist in [self.lkplist, self.evenlist, self.oddlist]:
+		for poslist in [self.evenlist, self.oddlist]:
 			for key, item in poslist.items():
-				if time.time() - item[2] > 900:
+				if time.time() - item[2] > 10:
 					del poslist[key]
 
 	def decode(self, icao24, encoded_lat, encoded_lon, cpr_format, surface):
@@ -194,30 +193,14 @@ class cpr_decoder:
 
 		[decoded_lat, decoded_lon] = [None, None]
 
-		#okay, let's traverse the lists and weed out those entries that are older than 15 minutes, as they're unlikely to be useful.
+		#okay, let's traverse the lists and weed out those entries that are older than 10 seconds
 		self.weed_poslists()
 
-		if icao24 in self.lkplist:
-			#do emitter-centered local decoding
-			[decoded_lat, decoded_lon] = cpr_resolve_local(self.lkplist[icao24][0:2], [encoded_lat, encoded_lon], cpr_format, surface)
-			self.lkplist[icao24] = [decoded_lat, decoded_lon, time.time()] #update the local position for next time
-
-		elif (icao24 in self.evenlist) \
-		  and (icao24 in self.oddlist) \
-		  and (abs(self.evenlist[icao24][2] - self.oddlist[icao24][2]) < 10) \
-		  and (surface == 0):
+		if (icao24 in self.evenlist) \
+		  and (icao24 in self.oddlist):
 			newer = (self.oddlist[icao24][2] - self.evenlist[icao24][2]) > 0 #figure out which report is newer
    			[decoded_lat, decoded_lon] = cpr_resolve_global(self.evenlist[icao24][0:2], self.oddlist[icao24][0:2], newer, surface) #do a global decode
-			self.lkplist[icao24] = [decoded_lat, decoded_lon, time.time()]
 
-		#so we really can't guarantee that local decoding will work unless you are POSITIVE that you can't hear more than 180nm out.
-		#this will USUALLY work, but you can't guarantee it!
-		#elif surface == 1 and self.my_location is not None:
-		#	[local_lat, local_lon] = cpr_resolve_local(self.my_location, [encoded_lat, encoded_lon], cpr_format, surface) #try local decoding
-		#	[rnge, bearing] = range_bearing(self.my_location, [local_lat, local_lon])
-		#	if rnge < validrange: #if the local decoding can be guaranteed valid
-		#		self.lkplist[icao24] = [local_lat, local_lon, time.time()] #update the local position for next time
-		#		[decoded_lat, decoded_lon] = [local_lat, local_lon]
 		else:
 			raise CPRNoPositionError
 
diff --git a/python/msprint.py b/python/msprint.py
index d613fa4..2349c35 100644
--- a/python/msprint.py
+++ b/python/msprint.py
@@ -69,7 +69,9 @@ class output_print(air_modes.parse):
       pass
 
   def output(self, msg):
-      print self.parse(msg)
+      parsed = self.parse(msg)
+      if parsed is not None:
+          print self.parse(msg)
 
   def print0(self, shortdata, ecc):
     [vs, cc, sl, ri, altitude] = self.parse0(shortdata)