diff --git a/apps/airprobe_rtlsdr.grc b/apps/airprobe_rtlsdr.grc
index 56fbfed..a65bafd 100644
--- a/apps/airprobe_rtlsdr.grc
+++ b/apps/airprobe_rtlsdr.grc
@@ -26,7 +26,7 @@
     </param>
     <param>
       <key>window_size</key>
-      <value>1280, 1024</value>
+      <value>2280, 1024</value>
     </param>
     <param>
       <key>generate_options</key>
@@ -69,7 +69,7 @@
     <key>variable</key>
     <param>
       <key>id</key>
-      <value>PCH</value>
+      <value>SDCCH</value>
     </param>
     <param>
       <key>_enabled</key>
@@ -77,7 +77,7 @@
     </param>
     <param>
       <key>value</key>
-      <value>5</value>
+      <value>6</value>
     </param>
     <param>
       <key>alias</key>
@@ -85,88 +85,7 @@
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(1128, 11)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable</key>
-    <param>
-      <key>id</key>
-      <value>AGCH</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>4</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(1056, 11)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable</key>
-    <param>
-      <key>id</key>
-      <value>RACH</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>3</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(984, 11)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable</key>
-    <param>
-      <key>id</key>
-      <value>CCCH</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>2</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(912, 11)</value>
+      <value>(1368, 11)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -193,7 +112,115 @@
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(840, 11)</value>
+      <value>(1008, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>CCCH</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1080, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>RACH</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>3</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1152, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>AGCH</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>4</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1224, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>PCH</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>5</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1296, 11)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -220,120 +247,7 @@
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(696, 11)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable</key>
-    <param>
-      <key>id</key>
-      <value>SDCCH</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>6</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(1200, 11)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable</key>
-    <param>
-      <key>id</key>
-      <value>samp_rate</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>2000000.052982</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(16, 83)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable_qtgui_range</key>
-    <param>
-      <key>id</key>
-      <value>g</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>label</key>
-      <value>Gain</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>43</value>
-    </param>
-    <param>
-      <key>start</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>stop</key>
-      <value>50</value>
-    </param>
-    <param>
-      <key>step</key>
-      <value>0.5</value>
-    </param>
-    <param>
-      <key>widget</key>
-      <value>counter</value>
-    </param>
-    <param>
-      <key>orient</key>
-      <value>Qt.Horizontal</value>
-    </param>
-    <param>
-      <key>min_len</key>
-      <value>100</value>
-    </param>
-    <param>
-      <key>gui_hint</key>
-      <value></value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(192, 11)</value>
+      <value>(864, 11)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -392,6 +306,535 @@
     </param>
   </block>
   <block>
+    <key>gsm_clock_offset_control</key>
+    <param>
+      <key>id</key>
+      <value>gsm_clock_offset_control_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>fc</key>
+      <value>fc</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>affinity</key>
+      <value></value>
+    </param>
+    <param>
+      <key>minoutbuf</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>maxoutbuf</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(344, 411)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>180</value>
+    </param>
+  </block>
+  <block>
+    <key>gsm_receiver</key>
+    <param>
+      <key>id</key>
+      <value>gsm_receiver_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>osr</key>
+      <value>4</value>
+    </param>
+    <param>
+      <key>cell_allocation</key>
+      <value>[0]</value>
+    </param>
+    <param>
+      <key>tseq_nums</key>
+      <value>[]</value>
+    </param>
+    <param>
+      <key>num_streams</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>affinity</key>
+      <value></value>
+    </param>
+    <param>
+      <key>minoutbuf</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>maxoutbuf</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(464, 288)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gsm_universal_ctrl_chans_demapper</key>
+    <param>
+      <key>id</key>
+      <value>gsm_universal_ctrl_chans_demapper_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>starts_fn_mod51</key>
+      <value>[2,6,12,16,22,26,32,36,42,46]</value>
+    </param>
+    <param>
+      <key>channel_types</key>
+      <value>[BCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH]</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>affinity</key>
+      <value></value>
+    </param>
+    <param>
+      <key>minoutbuf</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>maxoutbuf</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(656, 288)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gsm_control_channels_decoder</key>
+    <param>
+      <key>id</key>
+      <value>gsm_control_channels_decoder_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>affinity</key>
+      <value></value>
+    </param>
+    <param>
+      <key>minoutbuf</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>maxoutbuf</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(912, 288)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>blocks_socket_pdu</key>
+    <param>
+      <key>id</key>
+      <value>blocks_socket_pdu_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>"UDP_CLIENT"</value>
+    </param>
+    <param>
+      <key>host</key>
+      <value>127.0.0.1</value>
+    </param>
+    <param>
+      <key>port</key>
+      <value>4729</value>
+    </param>
+    <param>
+      <key>mtu</key>
+      <value>10000</value>
+    </param>
+    <param>
+      <key>tcp_no_delay</key>
+      <value>False</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>affinity</key>
+      <value></value>
+    </param>
+    <param>
+      <key>minoutbuf</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>maxoutbuf</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1152, 363)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gsm_message_printer</key>
+    <param>
+      <key>id</key>
+      <value>gsm_message_printer_1</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>prepend_string</key>
+      <value>""</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>affinity</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1152, 288)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>qtgui_freq_sink_x</key>
+    <param>
+      <key>id</key>
+      <value>qtgui_freq_sink_x_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>name</key>
+      <value>""</value>
+    </param>
+    <param>
+      <key>fftsize</key>
+      <value>1024</value>
+    </param>
+    <param>
+      <key>freqhalf</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>wintype</key>
+      <value>firdes.WIN_BLACKMAN_hARRIS</value>
+    </param>
+    <param>
+      <key>fc</key>
+      <value>fc</value>
+    </param>
+    <param>
+      <key>bw</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>grid</key>
+      <value>False</value>
+    </param>
+    <param>
+      <key>autoscale</key>
+      <value>False</value>
+    </param>
+    <param>
+      <key>average</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>ymin</key>
+      <value>-140</value>
+    </param>
+    <param>
+      <key>ymax</key>
+      <value>10</value>
+    </param>
+    <param>
+      <key>nconnections</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>update_time</key>
+      <value>0.10</value>
+    </param>
+    <param>
+      <key>gui_hint</key>
+      <value></value>
+    </param>
+    <param>
+      <key>showports</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>tr_mode</key>
+      <value>qtgui.TRIG_MODE_FREE</value>
+    </param>
+    <param>
+      <key>tr_level</key>
+      <value>0.0</value>
+    </param>
+    <param>
+      <key>tr_chan</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>tr_tag</key>
+      <value>""</value>
+    </param>
+    <param>
+      <key>label1</key>
+      <value></value>
+    </param>
+    <param>
+      <key>width1</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>color1</key>
+      <value>"blue"</value>
+    </param>
+    <param>
+      <key>alpha1</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>label2</key>
+      <value></value>
+    </param>
+    <param>
+      <key>width2</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>color2</key>
+      <value>"red"</value>
+    </param>
+    <param>
+      <key>alpha2</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>label3</key>
+      <value></value>
+    </param>
+    <param>
+      <key>width3</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>color3</key>
+      <value>"green"</value>
+    </param>
+    <param>
+      <key>alpha3</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>label4</key>
+      <value></value>
+    </param>
+    <param>
+      <key>width4</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>color4</key>
+      <value>"black"</value>
+    </param>
+    <param>
+      <key>alpha4</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>label5</key>
+      <value></value>
+    </param>
+    <param>
+      <key>width5</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>color5</key>
+      <value>"cyan"</value>
+    </param>
+    <param>
+      <key>alpha5</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>label6</key>
+      <value></value>
+    </param>
+    <param>
+      <key>width6</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>color6</key>
+      <value>"magenta"</value>
+    </param>
+    <param>
+      <key>alpha6</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>label7</key>
+      <value></value>
+    </param>
+    <param>
+      <key>width7</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>color7</key>
+      <value>"yellow"</value>
+    </param>
+    <param>
+      <key>alpha7</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>label8</key>
+      <value></value>
+    </param>
+    <param>
+      <key>width8</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>color8</key>
+      <value>"dark red"</value>
+    </param>
+    <param>
+      <key>alpha8</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>label9</key>
+      <value></value>
+    </param>
+    <param>
+      <key>width9</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>color9</key>
+      <value>"dark green"</value>
+    </param>
+    <param>
+      <key>alpha9</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>label10</key>
+      <value></value>
+    </param>
+    <param>
+      <key>width10</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>color10</key>
+      <value>"dark blue"</value>
+    </param>
+    <param>
+      <key>alpha10</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>affinity</key>
+      <value></value>
+    </param>
+    <param>
+      <key>minoutbuf</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>maxoutbuf</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(280, 187)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
     <key>rtlsdr_source</key>
     <param>
       <key>id</key>
@@ -491,11 +934,11 @@
     </param>
     <param>
       <key>freq0</key>
-      <value>fc</value>
+      <value>fc_slider</value>
     </param>
     <param>
       <key>corr0</key>
-      <value>ppm</value>
+      <value>ppm_slider</value>
     </param>
     <param>
       <key>dc_offset_mode0</key>
@@ -511,7 +954,7 @@
     </param>
     <param>
       <key>gain0</key>
-      <value>g</value>
+      <value>g_slider</value>
     </param>
     <param>
       <key>if_gain0</key>
@@ -1795,567 +2238,10 @@
     </param>
   </block>
   <block>
-    <key>qtgui_freq_sink_x</key>
-    <param>
-      <key>id</key>
-      <value>qtgui_freq_sink_x_0</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>type</key>
-      <value>complex</value>
-    </param>
-    <param>
-      <key>name</key>
-      <value>""</value>
-    </param>
-    <param>
-      <key>fftsize</key>
-      <value>1024</value>
-    </param>
-    <param>
-      <key>freqhalf</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>wintype</key>
-      <value>firdes.WIN_BLACKMAN_hARRIS</value>
-    </param>
-    <param>
-      <key>fc</key>
-      <value>fc</value>
-    </param>
-    <param>
-      <key>bw</key>
-      <value>samp_rate</value>
-    </param>
-    <param>
-      <key>grid</key>
-      <value>False</value>
-    </param>
-    <param>
-      <key>autoscale</key>
-      <value>False</value>
-    </param>
-    <param>
-      <key>average</key>
-      <value>1.0</value>
-    </param>
-    <param>
-      <key>ymin</key>
-      <value>-140</value>
-    </param>
-    <param>
-      <key>ymax</key>
-      <value>10</value>
-    </param>
-    <param>
-      <key>nconnections</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>update_time</key>
-      <value>0.10</value>
-    </param>
-    <param>
-      <key>gui_hint</key>
-      <value></value>
-    </param>
-    <param>
-      <key>showports</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>tr_mode</key>
-      <value>qtgui.TRIG_MODE_FREE</value>
-    </param>
-    <param>
-      <key>tr_level</key>
-      <value>0.0</value>
-    </param>
-    <param>
-      <key>tr_chan</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>tr_tag</key>
-      <value>""</value>
-    </param>
-    <param>
-      <key>label1</key>
-      <value></value>
-    </param>
-    <param>
-      <key>width1</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>color1</key>
-      <value>"blue"</value>
-    </param>
-    <param>
-      <key>alpha1</key>
-      <value>1.0</value>
-    </param>
-    <param>
-      <key>label2</key>
-      <value></value>
-    </param>
-    <param>
-      <key>width2</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>color2</key>
-      <value>"red"</value>
-    </param>
-    <param>
-      <key>alpha2</key>
-      <value>1.0</value>
-    </param>
-    <param>
-      <key>label3</key>
-      <value></value>
-    </param>
-    <param>
-      <key>width3</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>color3</key>
-      <value>"green"</value>
-    </param>
-    <param>
-      <key>alpha3</key>
-      <value>1.0</value>
-    </param>
-    <param>
-      <key>label4</key>
-      <value></value>
-    </param>
-    <param>
-      <key>width4</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>color4</key>
-      <value>"black"</value>
-    </param>
-    <param>
-      <key>alpha4</key>
-      <value>1.0</value>
-    </param>
-    <param>
-      <key>label5</key>
-      <value></value>
-    </param>
-    <param>
-      <key>width5</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>color5</key>
-      <value>"cyan"</value>
-    </param>
-    <param>
-      <key>alpha5</key>
-      <value>1.0</value>
-    </param>
-    <param>
-      <key>label6</key>
-      <value></value>
-    </param>
-    <param>
-      <key>width6</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>color6</key>
-      <value>"magenta"</value>
-    </param>
-    <param>
-      <key>alpha6</key>
-      <value>1.0</value>
-    </param>
-    <param>
-      <key>label7</key>
-      <value></value>
-    </param>
-    <param>
-      <key>width7</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>color7</key>
-      <value>"yellow"</value>
-    </param>
-    <param>
-      <key>alpha7</key>
-      <value>1.0</value>
-    </param>
-    <param>
-      <key>label8</key>
-      <value></value>
-    </param>
-    <param>
-      <key>width8</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>color8</key>
-      <value>"dark red"</value>
-    </param>
-    <param>
-      <key>alpha8</key>
-      <value>1.0</value>
-    </param>
-    <param>
-      <key>label9</key>
-      <value></value>
-    </param>
-    <param>
-      <key>width9</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>color9</key>
-      <value>"dark green"</value>
-    </param>
-    <param>
-      <key>alpha9</key>
-      <value>1.0</value>
-    </param>
-    <param>
-      <key>label10</key>
-      <value></value>
-    </param>
-    <param>
-      <key>width10</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>color10</key>
-      <value>"dark blue"</value>
-    </param>
-    <param>
-      <key>alpha10</key>
-      <value>1.0</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>affinity</key>
-      <value></value>
-    </param>
-    <param>
-      <key>minoutbuf</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>maxoutbuf</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(280, 187)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>gsm_clock_offset_control</key>
-    <param>
-      <key>id</key>
-      <value>gsm_clock_offset_control_0</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>fc</key>
-      <value>fc</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>affinity</key>
-      <value></value>
-    </param>
-    <param>
-      <key>minoutbuf</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>maxoutbuf</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(344, 411)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>180</value>
-    </param>
-  </block>
-  <block>
-    <key>gsm_receiver</key>
-    <param>
-      <key>id</key>
-      <value>gsm_receiver_0</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>osr</key>
-      <value>4</value>
-    </param>
-    <param>
-      <key>cell_allocation</key>
-      <value>[0]</value>
-    </param>
-    <param>
-      <key>tseq_nums</key>
-      <value>[]</value>
-    </param>
-    <param>
-      <key>num_streams</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>affinity</key>
-      <value></value>
-    </param>
-    <param>
-      <key>minoutbuf</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>maxoutbuf</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(464, 288)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>gsm_universal_ctrl_chans_demapper</key>
-    <param>
-      <key>id</key>
-      <value>gsm_universal_ctrl_chans_demapper_0</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>starts_fn_mod51</key>
-      <value>[2,6,12,16,22,26,32,36,42,46]</value>
-    </param>
-    <param>
-      <key>channel_types</key>
-      <value>[BCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH]</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>affinity</key>
-      <value></value>
-    </param>
-    <param>
-      <key>minoutbuf</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>maxoutbuf</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(656, 288)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>gsm_control_channels_decoder</key>
-    <param>
-      <key>id</key>
-      <value>gsm_control_channels_decoder_0</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>affinity</key>
-      <value></value>
-    </param>
-    <param>
-      <key>minoutbuf</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>maxoutbuf</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(912, 288)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>blocks_socket_pdu</key>
-    <param>
-      <key>id</key>
-      <value>blocks_socket_pdu_0</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>type</key>
-      <value>"UDP_CLIENT"</value>
-    </param>
-    <param>
-      <key>host</key>
-      <value>127.0.0.1</value>
-    </param>
-    <param>
-      <key>port</key>
-      <value>4729</value>
-    </param>
-    <param>
-      <key>mtu</key>
-      <value>10000</value>
-    </param>
-    <param>
-      <key>tcp_no_delay</key>
-      <value>False</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>affinity</key>
-      <value></value>
-    </param>
-    <param>
-      <key>minoutbuf</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>maxoutbuf</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(1152, 363)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
     <key>variable_qtgui_range</key>
     <param>
       <key>id</key>
-      <value>fc</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>label</key>
-      <value>Frequency</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>939.4e6</value>
-    </param>
-    <param>
-      <key>start</key>
-      <value>925e6</value>
-    </param>
-    <param>
-      <key>stop</key>
-      <value>960e6</value>
-    </param>
-    <param>
-      <key>step</key>
-      <value>2e5</value>
-    </param>
-    <param>
-      <key>widget</key>
-      <value>counter_slider</value>
-    </param>
-    <param>
-      <key>orient</key>
-      <value>Qt.Horizontal</value>
-    </param>
-    <param>
-      <key>min_len</key>
-      <value>100</value>
-    </param>
-    <param>
-      <key>gui_hint</key>
-      <value></value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(304, 11)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable_qtgui_range</key>
-    <param>
-      <key>id</key>
-      <value>ppm</value>
+      <value>ppm_slider</value>
     </param>
     <param>
       <key>_enabled</key>
@@ -2367,7 +2253,7 @@
     </param>
     <param>
       <key>value</key>
-      <value>ppm_param</value>
+      <value>ppm</value>
     </param>
     <param>
       <key>start</key>
@@ -2411,10 +2297,128 @@
     </param>
   </block>
   <block>
+    <key>variable_qtgui_range</key>
+    <param>
+      <key>id</key>
+      <value>g_slider</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Gain</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>gain</value>
+    </param>
+    <param>
+      <key>start</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>stop</key>
+      <value>50</value>
+    </param>
+    <param>
+      <key>step</key>
+      <value>0.5</value>
+    </param>
+    <param>
+      <key>widget</key>
+      <value>counter</value>
+    </param>
+    <param>
+      <key>orient</key>
+      <value>Qt.Horizontal</value>
+    </param>
+    <param>
+      <key>min_len</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>gui_hint</key>
+      <value></value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(192, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_qtgui_range</key>
+    <param>
+      <key>id</key>
+      <value>fc_slider</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Frequency</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>fc</value>
+    </param>
+    <param>
+      <key>start</key>
+      <value>925e6</value>
+    </param>
+    <param>
+      <key>stop</key>
+      <value>960e6</value>
+    </param>
+    <param>
+      <key>step</key>
+      <value>2e5</value>
+    </param>
+    <param>
+      <key>widget</key>
+      <value>counter_slider</value>
+    </param>
+    <param>
+      <key>orient</key>
+      <value>Qt.Horizontal</value>
+    </param>
+    <param>
+      <key>min_len</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>gui_hint</key>
+      <value></value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(304, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
     <key>parameter</key>
     <param>
       <key>id</key>
-      <value>ppm_param</value>
+      <value>ppm</value>
     </param>
     <param>
       <key>_enabled</key>
@@ -2442,7 +2446,7 @@
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(552, 27)</value>
+      <value>(744, 11)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -2450,30 +2454,116 @@
     </param>
   </block>
   <block>
-    <key>gsm_message_printer</key>
+    <key>parameter</key>
     <param>
       <key>id</key>
-      <value>gsm_message_printer_1</value>
+      <value>fc</value>
     </param>
     <param>
       <key>_enabled</key>
       <value>True</value>
     </param>
     <param>
-      <key>prepend_string</key>
-      <value>""</value>
+      <key>label</key>
+      <value>fc</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>939.4e6</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>eng_float</value>
+    </param>
+    <param>
+      <key>short_id</key>
+      <value>f</value>
     </param>
     <param>
       <key>alias</key>
       <value></value>
     </param>
     <param>
-      <key>affinity</key>
+      <key>_coordinate</key>
+      <value>(648, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>parameter</key>
+    <param>
+      <key>id</key>
+      <value>gain</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>gain</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>30</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>eng_float</value>
+    </param>
+    <param>
+      <key>short_id</key>
+      <value>g</value>
+    </param>
+    <param>
+      <key>alias</key>
       <value></value>
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(1152, 288)</value>
+      <value>(552, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>parameter</key>
+    <param>
+      <key>id</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>2000000.052982</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>eng_float</value>
+    </param>
+    <param>
+      <key>short_id</key>
+      <value>s</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(16, 75)</value>
     </param>
     <param>
       <key>_rotation</key>
diff --git a/apps/airprobe_rtlsdr.py b/apps/airprobe_rtlsdr.py
index c1f816d..8423acd 100755
--- a/apps/airprobe_rtlsdr.py
+++ b/apps/airprobe_rtlsdr.py
@@ -2,7 +2,7 @@
 ##################################################
 # Gnuradio Python Flow Graph
 # Title: Airprobe Rtlsdr
-# Generated: Sat Jan  3 00:02:56 2015
+# Generated: Sat Jan  3 00:30:45 2015
 ##################################################
 
 from PyQt4 import Qt
@@ -25,7 +25,7 @@
 from distutils.version import StrictVersion
 class airprobe_rtlsdr(gr.top_block, Qt.QWidget):
 
-    def __init__(self, ppm_param=0):
+    def __init__(self, ppm=0, fc=939.4e6, gain=30, samp_rate=2000000.052982):
         gr.top_block.__init__(self, "Airprobe Rtlsdr")
         Qt.QWidget.__init__(self)
         self.setWindowTitle("Airprobe Rtlsdr")
@@ -52,15 +52,17 @@
         ##################################################
         # Parameters
         ##################################################
-        self.ppm_param = ppm_param
+        self.ppm = ppm
+        self.fc = fc
+        self.gain = gain
+        self.samp_rate = samp_rate
 
         ##################################################
         # Variables
         ##################################################
-        self.samp_rate = samp_rate = 2000000.052982
-        self.ppm = ppm = ppm_param
-        self.g = g = 43
-        self.fc = fc = 939.4e6
+        self.ppm_slider = ppm_slider = ppm
+        self.g_slider = g_slider = gain
+        self.fc_slider = fc_slider = fc
         self.SDCCH = SDCCH = 6
         self.RACH = RACH = 3
         self.PCH = PCH = 5
@@ -72,69 +74,69 @@
         ##################################################
         # Blocks
         ##################################################
-        self._ppm_layout = Qt.QHBoxLayout()
-        self._ppm_layout.addWidget(Qt.QLabel("PPM Offset"+": "))
+        self._ppm_slider_layout = Qt.QHBoxLayout()
+        self._ppm_slider_layout.addWidget(Qt.QLabel("PPM Offset"+": "))
         class qwt_counter_pyslot(Qwt.QwtCounter):
             def __init__(self, parent=None):
                 Qwt.QwtCounter.__init__(self, parent)
             @pyqtSlot('double')
             def setValue(self, value):
                 super(Qwt.QwtCounter, self).setValue(value)
-        self._ppm_counter = qwt_counter_pyslot()
-        self._ppm_counter.setRange(-150, 150, 1)
-        self._ppm_counter.setNumButtons(2)
-        self._ppm_counter.setMinimumWidth(100)
-        self._ppm_counter.setValue(self.ppm)
-        self._ppm_layout.addWidget(self._ppm_counter)
-        self._ppm_counter.valueChanged.connect(self.set_ppm)
-        self.top_layout.addLayout(self._ppm_layout)
-        self._g_layout = Qt.QHBoxLayout()
-        self._g_layout.addWidget(Qt.QLabel("Gain"+": "))
+        self._ppm_slider_counter = qwt_counter_pyslot()
+        self._ppm_slider_counter.setRange(-150, 150, 1)
+        self._ppm_slider_counter.setNumButtons(2)
+        self._ppm_slider_counter.setMinimumWidth(100)
+        self._ppm_slider_counter.setValue(self.ppm_slider)
+        self._ppm_slider_layout.addWidget(self._ppm_slider_counter)
+        self._ppm_slider_counter.valueChanged.connect(self.set_ppm_slider)
+        self.top_layout.addLayout(self._ppm_slider_layout)
+        self._g_slider_layout = Qt.QHBoxLayout()
+        self._g_slider_layout.addWidget(Qt.QLabel("Gain"+": "))
         class qwt_counter_pyslot(Qwt.QwtCounter):
             def __init__(self, parent=None):
                 Qwt.QwtCounter.__init__(self, parent)
             @pyqtSlot('double')
             def setValue(self, value):
                 super(Qwt.QwtCounter, self).setValue(value)
-        self._g_counter = qwt_counter_pyslot()
-        self._g_counter.setRange(0, 50, 0.5)
-        self._g_counter.setNumButtons(2)
-        self._g_counter.setMinimumWidth(100)
-        self._g_counter.setValue(self.g)
-        self._g_layout.addWidget(self._g_counter)
-        self._g_counter.valueChanged.connect(self.set_g)
-        self.top_layout.addLayout(self._g_layout)
-        self._fc_layout = Qt.QVBoxLayout()
-        self._fc_tool_bar = Qt.QToolBar(self)
-        self._fc_layout.addWidget(self._fc_tool_bar)
-        self._fc_tool_bar.addWidget(Qt.QLabel("Frequency"+": "))
+        self._g_slider_counter = qwt_counter_pyslot()
+        self._g_slider_counter.setRange(0, 50, 0.5)
+        self._g_slider_counter.setNumButtons(2)
+        self._g_slider_counter.setMinimumWidth(100)
+        self._g_slider_counter.setValue(self.g_slider)
+        self._g_slider_layout.addWidget(self._g_slider_counter)
+        self._g_slider_counter.valueChanged.connect(self.set_g_slider)
+        self.top_layout.addLayout(self._g_slider_layout)
+        self._fc_slider_layout = Qt.QVBoxLayout()
+        self._fc_slider_tool_bar = Qt.QToolBar(self)
+        self._fc_slider_layout.addWidget(self._fc_slider_tool_bar)
+        self._fc_slider_tool_bar.addWidget(Qt.QLabel("Frequency"+": "))
         class qwt_counter_pyslot(Qwt.QwtCounter):
             def __init__(self, parent=None):
                 Qwt.QwtCounter.__init__(self, parent)
             @pyqtSlot('double')
             def setValue(self, value):
                 super(Qwt.QwtCounter, self).setValue(value)
-        self._fc_counter = qwt_counter_pyslot()
-        self._fc_counter.setRange(925e6, 960e6, 2e5)
-        self._fc_counter.setNumButtons(2)
-        self._fc_counter.setValue(self.fc)
-        self._fc_tool_bar.addWidget(self._fc_counter)
-        self._fc_counter.valueChanged.connect(self.set_fc)
-        self._fc_slider = Qwt.QwtSlider(None, Qt.Qt.Horizontal, Qwt.QwtSlider.BottomScale, Qwt.QwtSlider.BgSlot)
-        self._fc_slider.setRange(925e6, 960e6, 2e5)
-        self._fc_slider.setValue(self.fc)
-        self._fc_slider.setMinimumWidth(100)
-        self._fc_slider.valueChanged.connect(self.set_fc)
-        self._fc_layout.addWidget(self._fc_slider)
-        self.top_layout.addLayout(self._fc_layout)
+        self._fc_slider_counter = qwt_counter_pyslot()
+        self._fc_slider_counter.setRange(925e6, 960e6, 2e5)
+        self._fc_slider_counter.setNumButtons(2)
+        self._fc_slider_counter.setValue(self.fc_slider)
+        self._fc_slider_tool_bar.addWidget(self._fc_slider_counter)
+        self._fc_slider_counter.valueChanged.connect(self.set_fc_slider)
+        self._fc_slider_slider = Qwt.QwtSlider(None, Qt.Qt.Horizontal, Qwt.QwtSlider.BottomScale, Qwt.QwtSlider.BgSlot)
+        self._fc_slider_slider.setRange(925e6, 960e6, 2e5)
+        self._fc_slider_slider.setValue(self.fc_slider)
+        self._fc_slider_slider.setMinimumWidth(100)
+        self._fc_slider_slider.valueChanged.connect(self.set_fc_slider)
+        self._fc_slider_layout.addWidget(self._fc_slider_slider)
+        self.top_layout.addLayout(self._fc_slider_layout)
         self.rtlsdr_source_0 = osmosdr.source( args="numchan=" + str(1) + " " + "" )
         self.rtlsdr_source_0.set_sample_rate(samp_rate)
-        self.rtlsdr_source_0.set_center_freq(fc, 0)
-        self.rtlsdr_source_0.set_freq_corr(ppm, 0)
+        self.rtlsdr_source_0.set_center_freq(fc_slider, 0)
+        self.rtlsdr_source_0.set_freq_corr(ppm_slider, 0)
         self.rtlsdr_source_0.set_dc_offset_mode(2, 0)
         self.rtlsdr_source_0.set_iq_balance_mode(2, 0)
         self.rtlsdr_source_0.set_gain_mode(True, 0)
-        self.rtlsdr_source_0.set_gain(g, 0)
+        self.rtlsdr_source_0.set_gain(g_slider, 0)
         self.rtlsdr_source_0.set_if_gain(20, 0)
         self.rtlsdr_source_0.set_bb_gain(20, 0)
         self.rtlsdr_source_0.set_antenna("", 0)
@@ -212,37 +214,12 @@
         self.settings.setValue("geometry", self.saveGeometry())
         event.accept()
 
-    def get_ppm_param(self):
-        return self.ppm_param
-
-    def set_ppm_param(self, ppm_param):
-        self.ppm_param = ppm_param
-        self.set_ppm(self.ppm_param)
-
-    def get_samp_rate(self):
-        return self.samp_rate
-
-    def set_samp_rate(self, samp_rate):
-        self.samp_rate = samp_rate
-        self.gsm_input_0.set_samp_rate_in(self.samp_rate)
-        self.rtlsdr_source_0.set_sample_rate(self.samp_rate)
-        self.qtgui_freq_sink_x_0.set_frequency_range(self.fc, self.samp_rate)
-
     def get_ppm(self):
         return self.ppm
 
     def set_ppm(self, ppm):
         self.ppm = ppm
-        self.rtlsdr_source_0.set_freq_corr(self.ppm, 0)
-        Qt.QMetaObject.invokeMethod(self._ppm_counter, "setValue", Qt.Q_ARG("double", self.ppm))
-
-    def get_g(self):
-        return self.g
-
-    def set_g(self, g):
-        self.g = g
-        Qt.QMetaObject.invokeMethod(self._g_counter, "setValue", Qt.Q_ARG("double", self.g))
-        self.rtlsdr_source_0.set_gain(self.g, 0)
+        self.set_ppm_slider(self.ppm)
 
     def get_fc(self):
         return self.fc
@@ -250,10 +227,49 @@
     def set_fc(self, fc):
         self.fc = fc
         self.gsm_input_0.set_fc(self.fc)
-        self.rtlsdr_source_0.set_center_freq(self.fc, 0)
         self.qtgui_freq_sink_x_0.set_frequency_range(self.fc, self.samp_rate)
-        Qt.QMetaObject.invokeMethod(self._fc_counter, "setValue", Qt.Q_ARG("double", self.fc))
-        Qt.QMetaObject.invokeMethod(self._fc_slider, "setValue", Qt.Q_ARG("double", self.fc))
+        self.set_fc_slider(self.fc)
+
+    def get_gain(self):
+        return self.gain
+
+    def set_gain(self, gain):
+        self.gain = gain
+        self.set_g_slider(self.gain)
+
+    def get_samp_rate(self):
+        return self.samp_rate
+
+    def set_samp_rate(self, samp_rate):
+        self.samp_rate = samp_rate
+        self.gsm_input_0.set_samp_rate_in(self.samp_rate)
+        self.qtgui_freq_sink_x_0.set_frequency_range(self.fc, self.samp_rate)
+        self.rtlsdr_source_0.set_sample_rate(self.samp_rate)
+
+    def get_ppm_slider(self):
+        return self.ppm_slider
+
+    def set_ppm_slider(self, ppm_slider):
+        self.ppm_slider = ppm_slider
+        self.rtlsdr_source_0.set_freq_corr(self.ppm_slider, 0)
+        Qt.QMetaObject.invokeMethod(self._ppm_slider_counter, "setValue", Qt.Q_ARG("double", self.ppm_slider))
+
+    def get_g_slider(self):
+        return self.g_slider
+
+    def set_g_slider(self, g_slider):
+        self.g_slider = g_slider
+        self.rtlsdr_source_0.set_gain(self.g_slider, 0)
+        Qt.QMetaObject.invokeMethod(self._g_slider_counter, "setValue", Qt.Q_ARG("double", self.g_slider))
+
+    def get_fc_slider(self):
+        return self.fc_slider
+
+    def set_fc_slider(self, fc_slider):
+        self.fc_slider = fc_slider
+        self.rtlsdr_source_0.set_center_freq(self.fc_slider, 0)
+        Qt.QMetaObject.invokeMethod(self._fc_slider_counter, "setValue", Qt.Q_ARG("double", self.fc_slider))
+        Qt.QMetaObject.invokeMethod(self._fc_slider_slider, "setValue", Qt.Q_ARG("double", self.fc_slider))
 
     def get_SDCCH(self):
         return self.SDCCH
@@ -307,13 +323,19 @@
         except:
             print "Warning: failed to XInitThreads()"
     parser = OptionParser(option_class=eng_option, usage="%prog: [options]")
-    parser.add_option("-p", "--ppm-param", dest="ppm_param", type="intx", default=0,
+    parser.add_option("-p", "--ppm", dest="ppm", type="intx", default=0,
         help="Set ppm [default=%default]")
+    parser.add_option("-f", "--fc", dest="fc", type="eng_float", default=eng_notation.num_to_str(939.4e6),
+        help="Set fc [default=%default]")
+    parser.add_option("-g", "--gain", dest="gain", type="eng_float", default=eng_notation.num_to_str(30),
+        help="Set gain [default=%default]")
+    parser.add_option("-s", "--samp-rate", dest="samp_rate", type="eng_float", default=eng_notation.num_to_str(2000000.052982),
+        help="Set samp_rate [default=%default]")
     (options, args) = parser.parse_args()
     if(StrictVersion(Qt.qVersion()) >= StrictVersion("4.5.0")):
         Qt.QApplication.setGraphicsSystem(gr.prefs().get_string('qtgui','style','raster'))
     qapp = Qt.QApplication(sys.argv)
-    tb = airprobe_rtlsdr(ppm_param=options.ppm_param)
+    tb = airprobe_rtlsdr(ppm=options.ppm, fc=options.fc, gain=options.gain, samp_rate=options.samp_rate)
     tb.start()
     tb.show()
     def quitting():
diff --git a/apps/airprobe_usrp.grc b/apps/airprobe_usrp.grc
index 826c18d..08ec368 100644
--- a/apps/airprobe_usrp.grc
+++ b/apps/airprobe_usrp.grc
@@ -26,7 +26,7 @@
     </param>
     <param>
       <key>window_size</key>
-      <value>1280, 1024</value>
+      <value>2280, 1024</value>
     </param>
     <param>
       <key>generate_options</key>
@@ -69,33 +69,6 @@
     <key>variable</key>
     <param>
       <key>id</key>
-      <value>samp_rate</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>100e6/100</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(16, 99)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable</key>
-    <param>
-      <key>id</key>
       <value>CHANNEL_UNKNOWN</value>
     </param>
     <param>
@@ -112,142 +85,7 @@
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(608, 11)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable</key>
-    <param>
-      <key>id</key>
-      <value>BCCH</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(752, 11)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable</key>
-    <param>
-      <key>id</key>
-      <value>CCCH</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>2</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(824, 11)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable</key>
-    <param>
-      <key>id</key>
-      <value>SDCCH</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>6</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(1112, 11)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable</key>
-    <param>
-      <key>id</key>
-      <value>AGCH</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>4</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(968, 11)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable</key>
-    <param>
-      <key>id</key>
-      <value>RACH</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>3</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(896, 11)</value>
+      <value>(632, 11)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -274,7 +112,142 @@
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(1040, 11)</value>
+      <value>(1064, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>RACH</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>3</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(920, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>AGCH</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>4</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(992, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>CCCH</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(848, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>BCCH</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(776, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>SDCCH</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>6</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1136, 11)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -415,124 +388,6 @@
     </param>
   </block>
   <block>
-    <key>variable_qtgui_range</key>
-    <param>
-      <key>id</key>
-      <value>g</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>label</key>
-      <value>Gain</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>30</value>
-    </param>
-    <param>
-      <key>start</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>stop</key>
-      <value>50</value>
-    </param>
-    <param>
-      <key>step</key>
-      <value>0.5</value>
-    </param>
-    <param>
-      <key>widget</key>
-      <value>counter</value>
-    </param>
-    <param>
-      <key>orient</key>
-      <value>Qt.Horizontal</value>
-    </param>
-    <param>
-      <key>min_len</key>
-      <value>100</value>
-    </param>
-    <param>
-      <key>gui_hint</key>
-      <value></value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(192, 11)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable_qtgui_range</key>
-    <param>
-      <key>id</key>
-      <value>ppm</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>False</value>
-    </param>
-    <param>
-      <key>label</key>
-      <value>PPM Offset</value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>84</value>
-    </param>
-    <param>
-      <key>start</key>
-      <value>-100</value>
-    </param>
-    <param>
-      <key>stop</key>
-      <value>100</value>
-    </param>
-    <param>
-      <key>step</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>widget</key>
-      <value>counter</value>
-    </param>
-    <param>
-      <key>orient</key>
-      <value>Qt.Horizontal</value>
-    </param>
-    <param>
-      <key>min_len</key>
-      <value>100</value>
-    </param>
-    <param>
-      <key>gui_hint</key>
-      <value></value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(440, 11)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
     <key>gsm_input</key>
     <param>
       <key>id</key>
@@ -869,6 +724,10 @@
       <value>True</value>
     </param>
     <param>
+      <key>prepend_string</key>
+      <value></value>
+    </param>
+    <param>
       <key>alias</key>
       <value></value>
     </param>
@@ -937,6 +796,202 @@
     </param>
   </block>
   <block>
+    <key>variable_qtgui_range</key>
+    <param>
+      <key>id</key>
+      <value>g_slider</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Gain</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>gain</value>
+    </param>
+    <param>
+      <key>start</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>stop</key>
+      <value>50</value>
+    </param>
+    <param>
+      <key>step</key>
+      <value>0.5</value>
+    </param>
+    <param>
+      <key>widget</key>
+      <value>counter</value>
+    </param>
+    <param>
+      <key>orient</key>
+      <value>Qt.Horizontal</value>
+    </param>
+    <param>
+      <key>min_len</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>gui_hint</key>
+      <value></value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(176, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_qtgui_range</key>
+    <param>
+      <key>id</key>
+      <value>fc_slider</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Frequency</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>fc</value>
+    </param>
+    <param>
+      <key>start</key>
+      <value>925e6</value>
+    </param>
+    <param>
+      <key>stop</key>
+      <value>960e6</value>
+    </param>
+    <param>
+      <key>step</key>
+      <value>2e5</value>
+    </param>
+    <param>
+      <key>widget</key>
+      <value>counter_slider</value>
+    </param>
+    <param>
+      <key>orient</key>
+      <value>Qt.Horizontal</value>
+    </param>
+    <param>
+      <key>min_len</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>gui_hint</key>
+      <value></value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(288, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>parameter</key>
+    <param>
+      <key>id</key>
+      <value>gain</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>gain</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>30</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>eng_float</value>
+    </param>
+    <param>
+      <key>short_id</key>
+      <value>g</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(424, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>parameter</key>
+    <param>
+      <key>id</key>
+      <value>fc</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>fc</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>939.4e6</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>eng_float</value>
+    </param>
+    <param>
+      <key>short_id</key>
+      <value>f</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(504, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
     <key>uhd_usrp_source</key>
     <param>
       <key>id</key>
@@ -1088,11 +1143,11 @@
     </param>
     <param>
       <key>center_freq0</key>
-      <value>fc</value>
+      <value>fc_slider</value>
     </param>
     <param>
       <key>gain0</key>
-      <value>g</value>
+      <value>g_slider</value>
     </param>
     <param>
       <key>ant0</key>
@@ -1624,37 +1679,10 @@
     </param>
   </block>
   <block>
-    <key>blocks_message_debug</key>
+    <key>parameter</key>
     <param>
       <key>id</key>
-      <value>blocks_message_debug_0</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>affinity</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(672, 400)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>variable_qtgui_range</key>
-    <param>
-      <key>id</key>
-      <value>fc</value>
+      <value>samp_rate</value>
     </param>
     <param>
       <key>_enabled</key>
@@ -1662,39 +1690,19 @@
     </param>
     <param>
       <key>label</key>
-      <value>Frequency</value>
+      <value>samp_rate</value>
     </param>
     <param>
       <key>value</key>
-      <value>1869e6</value>
+      <value>2000000.052982</value>
     </param>
     <param>
-      <key>start</key>
-      <value>1800e6</value>
+      <key>type</key>
+      <value>eng_float</value>
     </param>
     <param>
-      <key>stop</key>
-      <value>1900e6</value>
-    </param>
-    <param>
-      <key>step</key>
-      <value>2e5</value>
-    </param>
-    <param>
-      <key>widget</key>
-      <value>counter_slider</value>
-    </param>
-    <param>
-      <key>orient</key>
-      <value>Qt.Horizontal</value>
-    </param>
-    <param>
-      <key>min_len</key>
-      <value>100</value>
-    </param>
-    <param>
-      <key>gui_hint</key>
-      <value></value>
+      <key>short_id</key>
+      <value>s</value>
     </param>
     <param>
       <key>alias</key>
@@ -1702,7 +1710,7 @@
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(304, 11)</value>
+      <value>(16, 83)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -1751,10 +1759,4 @@
     <source_key>C0</source_key>
     <sink_key>bursts</sink_key>
   </connection>
-  <connection>
-    <source_block_id>gsm_receiver_0</source_block_id>
-    <sink_block_id>blocks_message_debug_0</sink_block_id>
-    <source_key>measurements</source_key>
-    <sink_key>print</sink_key>
-  </connection>
 </flow_graph>
diff --git a/apps/airprobe_usrp.py b/apps/airprobe_usrp.py
index 63426a3..f87f8ee 100755
--- a/apps/airprobe_usrp.py
+++ b/apps/airprobe_usrp.py
@@ -2,7 +2,7 @@
 ##################################################
 # Gnuradio Python Flow Graph
 # Title: Airprobe Usrp
-# Generated: Sat Jan  3 00:02:32 2015
+# Generated: Sat Jan  3 00:30:50 2015
 ##################################################
 
 from PyQt4 import Qt
@@ -25,7 +25,7 @@
 from distutils.version import StrictVersion
 class airprobe_usrp(gr.top_block, Qt.QWidget):
 
-    def __init__(self):
+    def __init__(self, samp_rate=2000000.052982, gain=30, fc=939.4e6):
         gr.top_block.__init__(self, "Airprobe Usrp")
         Qt.QWidget.__init__(self)
         self.setWindowTitle("Airprobe Usrp")
@@ -50,11 +50,17 @@
 
 
         ##################################################
+        # Parameters
+        ##################################################
+        self.samp_rate = samp_rate
+        self.gain = gain
+        self.fc = fc
+
+        ##################################################
         # Variables
         ##################################################
-        self.samp_rate = samp_rate = 100e6/100
-        self.g = g = 30
-        self.fc = fc = 1869e6
+        self.g_slider = g_slider = gain
+        self.fc_slider = fc_slider = fc
         self.SDCCH = SDCCH = 6
         self.RACH = RACH = 3
         self.PCH = PCH = 5
@@ -66,45 +72,45 @@
         ##################################################
         # Blocks
         ##################################################
-        self._g_layout = Qt.QHBoxLayout()
-        self._g_layout.addWidget(Qt.QLabel("Gain"+": "))
+        self._g_slider_layout = Qt.QHBoxLayout()
+        self._g_slider_layout.addWidget(Qt.QLabel("Gain"+": "))
         class qwt_counter_pyslot(Qwt.QwtCounter):
             def __init__(self, parent=None):
                 Qwt.QwtCounter.__init__(self, parent)
             @pyqtSlot('double')
             def setValue(self, value):
                 super(Qwt.QwtCounter, self).setValue(value)
-        self._g_counter = qwt_counter_pyslot()
-        self._g_counter.setRange(0, 50, 0.5)
-        self._g_counter.setNumButtons(2)
-        self._g_counter.setMinimumWidth(100)
-        self._g_counter.setValue(self.g)
-        self._g_layout.addWidget(self._g_counter)
-        self._g_counter.valueChanged.connect(self.set_g)
-        self.top_layout.addLayout(self._g_layout)
-        self._fc_layout = Qt.QVBoxLayout()
-        self._fc_tool_bar = Qt.QToolBar(self)
-        self._fc_layout.addWidget(self._fc_tool_bar)
-        self._fc_tool_bar.addWidget(Qt.QLabel("Frequency"+": "))
+        self._g_slider_counter = qwt_counter_pyslot()
+        self._g_slider_counter.setRange(0, 50, 0.5)
+        self._g_slider_counter.setNumButtons(2)
+        self._g_slider_counter.setMinimumWidth(100)
+        self._g_slider_counter.setValue(self.g_slider)
+        self._g_slider_layout.addWidget(self._g_slider_counter)
+        self._g_slider_counter.valueChanged.connect(self.set_g_slider)
+        self.top_layout.addLayout(self._g_slider_layout)
+        self._fc_slider_layout = Qt.QVBoxLayout()
+        self._fc_slider_tool_bar = Qt.QToolBar(self)
+        self._fc_slider_layout.addWidget(self._fc_slider_tool_bar)
+        self._fc_slider_tool_bar.addWidget(Qt.QLabel("Frequency"+": "))
         class qwt_counter_pyslot(Qwt.QwtCounter):
             def __init__(self, parent=None):
                 Qwt.QwtCounter.__init__(self, parent)
             @pyqtSlot('double')
             def setValue(self, value):
                 super(Qwt.QwtCounter, self).setValue(value)
-        self._fc_counter = qwt_counter_pyslot()
-        self._fc_counter.setRange(1800e6, 1900e6, 2e5)
-        self._fc_counter.setNumButtons(2)
-        self._fc_counter.setValue(self.fc)
-        self._fc_tool_bar.addWidget(self._fc_counter)
-        self._fc_counter.valueChanged.connect(self.set_fc)
-        self._fc_slider = Qwt.QwtSlider(None, Qt.Qt.Horizontal, Qwt.QwtSlider.BottomScale, Qwt.QwtSlider.BgSlot)
-        self._fc_slider.setRange(1800e6, 1900e6, 2e5)
-        self._fc_slider.setValue(self.fc)
-        self._fc_slider.setMinimumWidth(100)
-        self._fc_slider.valueChanged.connect(self.set_fc)
-        self._fc_layout.addWidget(self._fc_slider)
-        self.top_layout.addLayout(self._fc_layout)
+        self._fc_slider_counter = qwt_counter_pyslot()
+        self._fc_slider_counter.setRange(925e6, 960e6, 2e5)
+        self._fc_slider_counter.setNumButtons(2)
+        self._fc_slider_counter.setValue(self.fc_slider)
+        self._fc_slider_tool_bar.addWidget(self._fc_slider_counter)
+        self._fc_slider_counter.valueChanged.connect(self.set_fc_slider)
+        self._fc_slider_slider = Qwt.QwtSlider(None, Qt.Qt.Horizontal, Qwt.QwtSlider.BottomScale, Qwt.QwtSlider.BgSlot)
+        self._fc_slider_slider.setRange(925e6, 960e6, 2e5)
+        self._fc_slider_slider.setValue(self.fc_slider)
+        self._fc_slider_slider.setMinimumWidth(100)
+        self._fc_slider_slider.valueChanged.connect(self.set_fc_slider)
+        self._fc_slider_layout.addWidget(self._fc_slider_slider)
+        self.top_layout.addLayout(self._fc_slider_layout)
         self.uhd_usrp_source_0 = uhd.usrp_source(
         	",".join(("addr=192.168.10.2", "")),
         	uhd.stream_args(
@@ -114,8 +120,8 @@
         )
         self.uhd_usrp_source_0.set_clock_source("internal", 0)
         self.uhd_usrp_source_0.set_samp_rate(samp_rate)
-        self.uhd_usrp_source_0.set_center_freq(fc, 0)
-        self.uhd_usrp_source_0.set_gain(g, 0)
+        self.uhd_usrp_source_0.set_center_freq(fc_slider, 0)
+        self.uhd_usrp_source_0.set_gain(g_slider, 0)
         self.qtgui_freq_sink_x_0 = qtgui.freq_sink_c(
         	1024, #size
         	firdes.WIN_BLACKMAN_hARRIS, #wintype
@@ -164,7 +170,6 @@
         )
         self.gsm_control_channels_decoder_0 = grgsm.control_channels_decoder()
         self.blocks_socket_pdu_0 = blocks.socket_pdu("UDP_CLIENT", "127.0.0.1", "4729", 10000, False)
-        self.blocks_message_debug_0 = blocks.message_debug()
 
         ##################################################
         # Connections
@@ -180,7 +185,6 @@
         self.msg_connect(self.gsm_control_channels_decoder_0, "msgs", self.blocks_socket_pdu_0, "pdus")
         self.msg_connect(self.gsm_universal_ctrl_chans_demapper_0, "bursts", self.gsm_control_channels_decoder_0, "bursts")
         self.msg_connect(self.gsm_receiver_0, "C0", self.gsm_universal_ctrl_chans_demapper_0, "bursts")
-        self.msg_connect(self.gsm_receiver_0, "measurements", self.blocks_message_debug_0, "print")
 
     def closeEvent(self, event):
         self.settings = Qt.QSettings("GNU Radio", "airprobe_usrp")
@@ -196,13 +200,12 @@
         self.qtgui_freq_sink_x_0.set_frequency_range(self.fc, self.samp_rate)
         self.uhd_usrp_source_0.set_samp_rate(self.samp_rate)
 
-    def get_g(self):
-        return self.g
+    def get_gain(self):
+        return self.gain
 
-    def set_g(self, g):
-        self.g = g
-        Qt.QMetaObject.invokeMethod(self._g_counter, "setValue", Qt.Q_ARG("double", self.g))
-        self.uhd_usrp_source_0.set_gain(self.g, 0)
+    def set_gain(self, gain):
+        self.gain = gain
+        self.set_g_slider(self.gain)
 
     def get_fc(self):
         return self.fc
@@ -211,9 +214,24 @@
         self.fc = fc
         self.gsm_input_0.set_fc(self.fc)
         self.qtgui_freq_sink_x_0.set_frequency_range(self.fc, self.samp_rate)
-        self.uhd_usrp_source_0.set_center_freq(self.fc, 0)
-        Qt.QMetaObject.invokeMethod(self._fc_counter, "setValue", Qt.Q_ARG("double", self.fc))
-        Qt.QMetaObject.invokeMethod(self._fc_slider, "setValue", Qt.Q_ARG("double", self.fc))
+        self.set_fc_slider(self.fc)
+
+    def get_g_slider(self):
+        return self.g_slider
+
+    def set_g_slider(self, g_slider):
+        self.g_slider = g_slider
+        Qt.QMetaObject.invokeMethod(self._g_slider_counter, "setValue", Qt.Q_ARG("double", self.g_slider))
+        self.uhd_usrp_source_0.set_gain(self.g_slider, 0)
+
+    def get_fc_slider(self):
+        return self.fc_slider
+
+    def set_fc_slider(self, fc_slider):
+        self.fc_slider = fc_slider
+        Qt.QMetaObject.invokeMethod(self._fc_slider_counter, "setValue", Qt.Q_ARG("double", self.fc_slider))
+        Qt.QMetaObject.invokeMethod(self._fc_slider_slider, "setValue", Qt.Q_ARG("double", self.fc_slider))
+        self.uhd_usrp_source_0.set_center_freq(self.fc_slider, 0)
 
     def get_SDCCH(self):
         return self.SDCCH
@@ -267,11 +285,17 @@
         except:
             print "Warning: failed to XInitThreads()"
     parser = OptionParser(option_class=eng_option, usage="%prog: [options]")
+    parser.add_option("-s", "--samp-rate", dest="samp_rate", type="eng_float", default=eng_notation.num_to_str(2000000.052982),
+        help="Set samp_rate [default=%default]")
+    parser.add_option("-g", "--gain", dest="gain", type="eng_float", default=eng_notation.num_to_str(30),
+        help="Set gain [default=%default]")
+    parser.add_option("-f", "--fc", dest="fc", type="eng_float", default=eng_notation.num_to_str(939.4e6),
+        help="Set fc [default=%default]")
     (options, args) = parser.parse_args()
     if(StrictVersion(Qt.qVersion()) >= StrictVersion("4.5.0")):
         Qt.QApplication.setGraphicsSystem(gr.prefs().get_string('qtgui','style','raster'))
     qapp = Qt.QApplication(sys.argv)
-    tb = airprobe_usrp()
+    tb = airprobe_usrp(samp_rate=options.samp_rate, gain=options.gain, fc=options.fc)
     tb.start()
     tb.show()
     def quitting():