diff --git a/apps/modes_gui b/apps/modes_gui
index 01f9a28..9a8ffb6 100755
--- a/apps/modes_gui
+++ b/apps/modes_gui
@@ -58,12 +58,14 @@ class mainwindow(QtGui.QMainWindow):
 
         if defaults["pmf"] is not None:
             self.ui.check_pmf.setChecked(bool(defaults["pmf"]))
+        if defaults["dcblock"] is not None:
+            self.ui.check_dcblock.setChecked(bool(defaults["dcblock"]))
         if defaults["samplerate"] is not None:
             if defaults["samplerate"] in self.rates:
                 self.ui.combo_rate.setCurrentIndex(self.rates.index(int(defaults["samplerate"])))
 
-        self.ui.prog_rssi.setMinimum(0)
-        self.ui.prog_rssi.setMaximum(40)
+        self.ui.prog_rssi.setMinimum(-60)
+        self.ui.prog_rssi.setMaximum(0)
 
         if defaults["antenna"] is None:
             self.ui.combo_ant.setCurrentIndex(self.ui.combo_ant.findText("RX2"))
@@ -295,6 +297,7 @@ class mainwindow(QtGui.QMainWindow):
             options.gain = float(self.ui.line_gain.text())
             options.threshold = float(self.ui.line_threshold.text())
             options.pmf = self.ui.check_pmf.isChecked()
+            options.dcblock = self.ui.check_dcblock.isChecked()
 
             self._servers = ["inproc://modes-radio-pub"] #TODO ADD REMOTES
             self._relay = air_modes.zmq_pubsub_iface(self.context, subaddr=self._servers, pubaddr=None)
@@ -378,6 +381,7 @@ class mainwindow(QtGui.QMainWindow):
             self.prefs["antenna"] = options.antenna
             self.prefs["gain"] = options.gain
             self.prefs["pmf"] = "1" if options.pmf else "0"
+            self.prefs["dcblock"] = "1" if options.dcblock else "0"
             self.prefs["source"] = self.ui.combo_source.currentText()
             self.prefs["threshold"] = options.threshold
             self.prefs["sbs1"] = "1" if self.ui.check_sbs1.isChecked() else "0"
@@ -437,6 +441,7 @@ class mainwindow(QtGui.QMainWindow):
         defaults = {}
         defaults["samplerate"] = None #let app pick it
         defaults["pmf"] = None
+        defaults["dcblock"] = None
         defaults["antenna"] = None
         defaults["gain"] = "25"
         defaults["kml"] = "1"
diff --git a/python/parse.py b/python/parse.py
index 4b1a19f..7fe3297 100644
--- a/python/parse.py
+++ b/python/parse.py
@@ -427,7 +427,7 @@ def make_parser(pub):
     try:
       ret = air_modes.modes_report(modes_reply(int(data, 16)),
                                    int(ecc, 16),
-                                   10.0*math.log10(float(reference)),
+                                   10.0*math.log10(max(1e-8,float(reference))),
                                    air_modes.stamp(0, float(timestamp)))
       pub["modes_dl"] = ret
       pub["type%i_dl" % ret.data.get_type()] = ret
diff --git a/python/radio.py b/python/radio.py
index d8a77e1..ebdfa7f 100644
--- a/python/radio.py
+++ b/python/radio.py
@@ -45,7 +45,8 @@ class modes_radio (gr.top_block, pubsub):
     self._resample = None
     self._setup_source(options)
 
-    self._rx_path = air_modes.rx_path(self._rate, options.threshold, self._queue, options.pmf)
+    self._rx_path = air_modes.rx_path(self._rate, options.threshold,
+                                      self._queue, options.pmf, options.dcblock)
 
     #now subscribe to set various options via pubsub
     self.subscribe("freq", self.set_freq)
@@ -106,6 +107,8 @@ class modes_radio (gr.top_block, pubsub):
                       help="set pulse detection threshold above noise in dB [default=%default]")
     group.add_option("-p","--pmf", action="store_true", default=False,
                       help="Use pulse matched filtering [default=%default]")
+    group.add_option("-d","--dcblock", action="store_true", default=False,
+                      help="Use a DC blocking filter (best for HackRF Jawbreaker) [default=%default]")
 
     parser.add_option_group(group)
 
@@ -186,8 +189,9 @@ class modes_radio (gr.top_block, pubsub):
             options.gain = 34
 ###DO NOT COMMIT
         self._u.set_gain(14, "RF", 0)
-        self._u.set_gain(40, "IF", 0)
+        self._u.set_gain(30, "IF", 0)
         self._u.set_gain(6, "BB", 0)
+        self._u.set_bandwidth(4e6)
 ###DO NOT COMMIT
 #        self._u.set_gain(options.gain)
         print "Gain is %i" % self._u.get_gain()
diff --git a/python/rx_path.py b/python/rx_path.py
index e148f4e..fa13889 100644
--- a/python/rx_path.py
+++ b/python/rx_path.py
@@ -24,7 +24,7 @@ import air_modes_swig
 
 class rx_path(gr.hier_block2):
 
-    def __init__(self, rate, threshold, queue, use_pmf=False):
+    def __init__(self, rate, threshold, queue, use_pmf=False, use_dcblock=False):
         gr.hier_block2.__init__(self, "modes_rx_path",
                                 gr.io_signature(1, 1, gr.sizeof_gr_complex),
                                 gr.io_signature(0,0,0))
@@ -36,9 +36,13 @@ class rx_path(gr.hier_block2):
 
         # Convert incoming I/Q baseband to amplitude
         self._demod = blocks.complex_to_mag_squared()
-#        self._dcblock = filter.dc_blocker_ff(128, False)
-        self._bb = self._demod
+        if use_dcblock:
+            self._dcblock = filter.dc_blocker_cc(100*self._spc,True)
+            self.connect(self, self._dcblock, self._demod)
+        else:
+            self.connect(self, self._demod)
 
+        self._bb = self._demod
         # Pulse matched filter for 0.5us pulses
         if use_pmf:
             self._pmf = blocks.moving_average_ff(self._spc, 1.0/self._spc)#, self._rate)
@@ -55,7 +59,6 @@ class rx_path(gr.hier_block2):
         self._slicer = air_modes_swig.slicer(self._queue)
 
         # Wire up the flowgraph
-        self.connect(self, self._demod)#, self._dcblock)
         self.connect(self._bb, (self._sync, 0))
         self.connect(self._bb, self._avg, (self._sync, 1))
         self.connect(self._sync, self._slicer)
diff --git a/res/modes_rx.ui b/res/modes_rx.ui
index 9698649..52e5793 100644
--- a/res/modes_rx.ui
+++ b/res/modes_rx.ui
@@ -316,6 +316,19 @@
               <string>Use Pulse Matched Filtering</string>
              </property>
             </widget>
+            <widget class="QCheckBox" name="check_dcblock">
+             <property name="geometry">
+              <rect>
+               <x>10</x>
+               <y>220</y>
+               <width>221</width>
+               <height>22</height>
+              </rect>
+             </property>
+             <property name="text">
+              <string>Use DC blocking filter</string>
+             </property>
+            </widget>
            </widget>
            <widget class="QGroupBox" name="group_output">
             <property name="geometry">