diff --git a/apps/osmosdr_source_1rtl.grc b/apps/osmosdr_source_1rtl.grc
index 2333b24..9557d27 100644
--- a/apps/osmosdr_source_1rtl.grc
+++ b/apps/osmosdr_source_1rtl.grc
@@ -1,6 +1,6 @@
 <?xml version='1.0' encoding='ASCII'?>
 <flow_graph>
-  <timestamp>Tue May 15 18:29:06 2012</timestamp>
+  <timestamp>Wed Jul 18 20:58:31 2012</timestamp>
   <block>
     <key>options</key>
     <param>
@@ -115,61 +115,6 @@
       <value>0</value>
     </param>
   </block>
-  <block>
-    <key>variable_slider</key>
-    <param>
-      <key>id</key>
-      <value>gain_slider</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>label</key>
-      <value></value>
-    </param>
-    <param>
-      <key>value</key>
-      <value>10</value>
-    </param>
-    <param>
-      <key>min</key>
-      <value>-1</value>
-    </param>
-    <param>
-      <key>max</key>
-      <value>50</value>
-    </param>
-    <param>
-      <key>num_steps</key>
-      <value>52</value>
-    </param>
-    <param>
-      <key>style</key>
-      <value>wx.SL_HORIZONTAL</value>
-    </param>
-    <param>
-      <key>converver</key>
-      <value>float_converter</value>
-    </param>
-    <param>
-      <key>grid_pos</key>
-      <value></value>
-    </param>
-    <param>
-      <key>notebook</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(570, 68)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
   <block>
     <key>variable_slider</key>
     <param>
@@ -295,6 +240,10 @@
       <key>notebook</key>
       <value></value>
     </param>
+    <param>
+      <key>freqvar</key>
+      <value>None</value>
+    </param>
     <param>
       <key>_coordinate</key>
       <value>(517, 399)</value>
@@ -382,6 +331,10 @@
       <key>notebook</key>
       <value></value>
     </param>
+    <param>
+      <key>freqvar</key>
+      <value>None</value>
+    </param>
     <param>
       <key>_coordinate</key>
       <value>(517, 208)</value>
@@ -391,141 +344,6 @@
       <value>0</value>
     </param>
   </block>
-  <block>
-    <key>osmosdr_source_c</key>
-    <param>
-      <key>id</key>
-      <value>osmosdr_source_c_0</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>type</key>
-      <value>fc32</value>
-    </param>
-    <param>
-      <key>args</key>
-      <value></value>
-    </param>
-    <param>
-      <key>nchan</key>
-      <value>1</value>
-    </param>
-    <param>
-      <key>sample_rate</key>
-      <value>samp_rate</value>
-    </param>
-    <param>
-      <key>freq0</key>
-      <value>freq</value>
-    </param>
-    <param>
-      <key>corr0</key>
-      <value>corr_ppm</value>
-    </param>
-    <param>
-      <key>gain0</key>
-      <value>gain_slider</value>
-    </param>
-    <param>
-      <key>gain_mode0</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>ant0</key>
-      <value></value>
-    </param>
-    <param>
-      <key>freq1</key>
-      <value>freq</value>
-    </param>
-    <param>
-      <key>corr1</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>gain1</key>
-      <value>gain_slider</value>
-    </param>
-    <param>
-      <key>gain_mode1</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>ant1</key>
-      <value></value>
-    </param>
-    <param>
-      <key>freq2</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>corr2</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>gain2</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>gain_mode2</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>ant2</key>
-      <value></value>
-    </param>
-    <param>
-      <key>freq3</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>corr3</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>gain3</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>gain_mode3</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>ant3</key>
-      <value></value>
-    </param>
-    <param>
-      <key>freq4</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>corr4</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>gain4</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>gain_mode4</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>ant4</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(76, 324)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
   <block>
     <key>variable_slider</key>
     <param>
@@ -581,6 +399,271 @@
       <value>0</value>
     </param>
   </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>gain</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value></value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>10</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>-1</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>50</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>52</value>
+    </param>
+    <param>
+      <key>style</key>
+      <value>wx.SL_HORIZONTAL</value>
+    </param>
+    <param>
+      <key>converver</key>
+      <value>float_converter</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value></value>
+    </param>
+    <param>
+      <key>notebook</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(570, 68)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>if_gain</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value></value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>20</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>40</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>41</value>
+    </param>
+    <param>
+      <key>style</key>
+      <value>wx.SL_HORIZONTAL</value>
+    </param>
+    <param>
+      <key>converver</key>
+      <value>float_converter</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value></value>
+    </param>
+    <param>
+      <key>notebook</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(708, 67)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>osmosdr_source_c</key>
+    <param>
+      <key>id</key>
+      <value>osmosdr_source_c_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>fc32</value>
+    </param>
+    <param>
+      <key>args</key>
+      <value></value>
+    </param>
+    <param>
+      <key>nchan</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>sample_rate</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>freq0</key>
+      <value>freq</value>
+    </param>
+    <param>
+      <key>corr0</key>
+      <value>corr_ppm</value>
+    </param>
+    <param>
+      <key>gain_mode0</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>gain0</key>
+      <value>gain</value>
+    </param>
+    <param>
+      <key>if_gain0</key>
+      <value>if_gain</value>
+    </param>
+    <param>
+      <key>ant0</key>
+      <value></value>
+    </param>
+    <param>
+      <key>freq1</key>
+      <value>freq</value>
+    </param>
+    <param>
+      <key>corr1</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>gain_mode1</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>gain1</key>
+      <value>gain</value>
+    </param>
+    <param>
+      <key>if_gain1</key>
+      <value>if_gain</value>
+    </param>
+    <param>
+      <key>ant1</key>
+      <value></value>
+    </param>
+    <param>
+      <key>freq2</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>corr2</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>gain_mode2</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>gain2</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>if_gain2</key>
+      <value>20</value>
+    </param>
+    <param>
+      <key>ant2</key>
+      <value></value>
+    </param>
+    <param>
+      <key>freq3</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>corr3</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>gain_mode3</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>gain3</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>if_gain3</key>
+      <value>20</value>
+    </param>
+    <param>
+      <key>ant3</key>
+      <value></value>
+    </param>
+    <param>
+      <key>freq4</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>corr4</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>gain_mode4</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>gain4</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>if_gain4</key>
+      <value>20</value>
+    </param>
+    <param>
+      <key>ant4</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(76, 324)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
   <connection>
     <source_block_id>osmosdr_source_c_0</source_block_id>
     <sink_block_id>wxgui_fftsink2_0</sink_block_id>
diff --git a/apps/osmosdr_source_2rtl.grc b/apps/osmosdr_source_2rtl.grc
index f6cc423..aed147d 100644
--- a/apps/osmosdr_source_2rtl.grc
+++ b/apps/osmosdr_source_2rtl.grc
@@ -1,6 +1,6 @@
 <?xml version='1.0' encoding='ASCII'?>
 <flow_graph>
-  <timestamp>Tue May 15 18:30:25 2012</timestamp>
+  <timestamp>Wed Jul 18 20:57:38 2012</timestamp>
   <block>
     <key>options</key>
     <param>
@@ -193,6 +193,10 @@
       <key>notebook</key>
       <value></value>
     </param>
+    <param>
+      <key>freqvar</key>
+      <value>None</value>
+    </param>
     <param>
       <key>_coordinate</key>
       <value>(718, 318)</value>
@@ -280,6 +284,10 @@
       <key>notebook</key>
       <value></value>
     </param>
+    <param>
+      <key>freqvar</key>
+      <value>None</value>
+    </param>
     <param>
       <key>_coordinate</key>
       <value>(717, 114)</value>
@@ -348,7 +356,7 @@
     <key>variable_slider</key>
     <param>
       <key>id</key>
-      <value>gain_slider</value>
+      <value>gain</value>
     </param>
     <param>
       <key>_enabled</key>
@@ -399,6 +407,61 @@
       <value>0</value>
     </param>
   </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>if_gain</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value></value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>20</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>40</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>41</value>
+    </param>
+    <param>
+      <key>style</key>
+      <value>wx.SL_HORIZONTAL</value>
+    </param>
+    <param>
+      <key>converver</key>
+      <value>float_converter</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value></value>
+    </param>
+    <param>
+      <key>notebook</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(600, 60)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
   <block>
     <key>osmosdr_source_c</key>
     <param>
@@ -433,14 +496,18 @@
       <key>corr0</key>
       <value>0</value>
     </param>
-    <param>
-      <key>gain0</key>
-      <value>gain_slider</value>
-    </param>
     <param>
       <key>gain_mode0</key>
       <value>0</value>
     </param>
+    <param>
+      <key>gain0</key>
+      <value>gain</value>
+    </param>
+    <param>
+      <key>if_gain0</key>
+      <value>if_gain</value>
+    </param>
     <param>
       <key>ant0</key>
       <value></value>
@@ -453,14 +520,18 @@
       <key>corr1</key>
       <value>0</value>
     </param>
-    <param>
-      <key>gain1</key>
-      <value>gain_slider</value>
-    </param>
     <param>
       <key>gain_mode1</key>
       <value>0</value>
     </param>
+    <param>
+      <key>gain1</key>
+      <value>gain</value>
+    </param>
+    <param>
+      <key>if_gain1</key>
+      <value>if_gain</value>
+    </param>
     <param>
       <key>ant1</key>
       <value></value>
@@ -473,13 +544,17 @@
       <key>corr2</key>
       <value>0</value>
     </param>
+    <param>
+      <key>gain_mode2</key>
+      <value>0</value>
+    </param>
     <param>
       <key>gain2</key>
       <value>0</value>
     </param>
     <param>
-      <key>gain_mode2</key>
-      <value>0</value>
+      <key>if_gain2</key>
+      <value>20</value>
     </param>
     <param>
       <key>ant2</key>
@@ -493,13 +568,17 @@
       <key>corr3</key>
       <value>0</value>
     </param>
+    <param>
+      <key>gain_mode3</key>
+      <value>0</value>
+    </param>
     <param>
       <key>gain3</key>
       <value>0</value>
     </param>
     <param>
-      <key>gain_mode3</key>
-      <value>0</value>
+      <key>if_gain3</key>
+      <value>20</value>
     </param>
     <param>
       <key>ant3</key>
@@ -513,13 +592,17 @@
       <key>corr4</key>
       <value>0</value>
     </param>
+    <param>
+      <key>gain_mode4</key>
+      <value>0</value>
+    </param>
     <param>
       <key>gain4</key>
       <value>0</value>
     </param>
     <param>
-      <key>gain_mode4</key>
-      <value>0</value>
+      <key>if_gain4</key>
+      <value>20</value>
     </param>
     <param>
       <key>ant4</key>