diff --git a/apps/CMakeLists.txt b/apps/CMakeLists.txt
index a3fbed1..766a037 100644
--- a/apps/CMakeLists.txt
+++ b/apps/CMakeLists.txt
@@ -24,5 +24,7 @@
 GR_PYTHON_INSTALL(
     PROGRAMS
 #    ${PYFILES}
+    airprobe_file.py
+    airprobe_rtlsdr.py
     DESTINATION bin
 )
diff --git a/apps/README b/apps/README
new file mode 100644
index 0000000..1106ef5
--- /dev/null
+++ b/apps/README
@@ -0,0 +1,6 @@
+This directory contains programs based on gr-gsm. Currently two are available:
+- airprobe_rtlsdr.py
+- airprobe_file.py
+
+- airprobe_usrp can be used but it will need to be customized in the gnuradio-companion for given configuration (for example address of the USRP will need to be changed).
+
diff --git a/apps/airprobe_file.py b/apps/airprobe_file.py
new file mode 100755
index 0000000..d981d2f
--- /dev/null
+++ b/apps/airprobe_file.py
@@ -0,0 +1,147 @@
+#!/usr/bin/env python
+##################################################
+# Gnuradio Python Flow Graph
+# Title: Airprobe File
+# Generated: Fri Nov 28 23:19:07 2014
+##################################################
+
+from gnuradio import blocks
+from gnuradio import eng_notation
+from gnuradio import gr
+from gnuradio.eng_option import eng_option
+from gnuradio.filter import firdes
+from optparse import OptionParser
+import gsm
+
+class airprobe_file(gr.top_block):
+
+    def __init__(self, input_file_name="input.cfile", fc=937e6, samp_rate=1e6):
+        gr.top_block.__init__(self, "Airprobe File")
+
+        ##################################################
+        # Parameters
+        ##################################################
+        self.input_file_name = input_file_name
+        self.fc = fc
+        self.samp_rate = samp_rate
+
+        ##################################################
+        # Variables
+        ##################################################
+        self.SDCCH = SDCCH = 6
+        self.RACH = RACH = 3
+        self.PCH = PCH = 5
+        self.CHANNEL_UNKNOWN = CHANNEL_UNKNOWN = 0
+        self.CCCH = CCCH = 2
+        self.BCCH = BCCH = 1
+        self.AGCH = AGCH = 4
+
+        ##################################################
+        # Blocks
+        ##################################################
+        self.gsm_universal_ctrl_chans_demapper_0 = gsm.universal_ctrl_chans_demapper(([2,6,12,16,22,26,32,36,42,46]), ([BCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH]))
+        self.gsm_receiver_0 = gsm.receiver(4, ([0]), ([]))
+        self.gsm_message_printer_0 = gsm.message_printer()
+        self.gsm_input_0 = gsm.gsm_input(
+            ppm=0,
+            osr=4,
+            fc=fc,
+            samp_rate_in=samp_rate,
+        )
+        self.gsm_control_channels_decoder_0 = gsm.control_channels_decoder()
+        self.gsm_clock_offset_control_0 = gsm.clock_offset_control(fc, samp_rate)
+        self.blocks_socket_pdu_0 = blocks.socket_pdu("UDP_CLIENT", "127.0.0.1", "4729", 10000, False)
+        self.blocks_file_source_0 = blocks.file_source(gr.sizeof_gr_complex*1, input_file_name, False)
+
+        ##################################################
+        # Connections
+        ##################################################
+        self.connect((self.gsm_input_0, 0), (self.gsm_receiver_0, 0))
+        self.connect((self.blocks_file_source_0, 0), (self.gsm_input_0, 0))
+
+        ##################################################
+        # Asynch Message Connections
+        ##################################################
+        self.msg_connect(self.gsm_receiver_0, "measurements", self.gsm_clock_offset_control_0, "measurements")
+        self.msg_connect(self.gsm_control_channels_decoder_0, "msgs", self.gsm_message_printer_0, "msgs")
+        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_clock_offset_control_0, "ppm", self.gsm_input_0, "ppm_in")
+        self.msg_connect(self.gsm_control_channels_decoder_0, "msgs", self.blocks_socket_pdu_0, "pdus")
+
+
+    def get_input_file_name(self):
+        return self.input_file_name
+
+    def set_input_file_name(self, input_file_name):
+        self.input_file_name = input_file_name
+        self.blocks_file_source_0.open(self.input_file_name, False)
+
+    def get_fc(self):
+        return self.fc
+
+    def set_fc(self, fc):
+        self.fc = fc
+        self.gsm_input_0.set_fc(self.fc)
+
+    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)
+
+    def get_SDCCH(self):
+        return self.SDCCH
+
+    def set_SDCCH(self, SDCCH):
+        self.SDCCH = SDCCH
+
+    def get_RACH(self):
+        return self.RACH
+
+    def set_RACH(self, RACH):
+        self.RACH = RACH
+
+    def get_PCH(self):
+        return self.PCH
+
+    def set_PCH(self, PCH):
+        self.PCH = PCH
+
+    def get_CHANNEL_UNKNOWN(self):
+        return self.CHANNEL_UNKNOWN
+
+    def set_CHANNEL_UNKNOWN(self, CHANNEL_UNKNOWN):
+        self.CHANNEL_UNKNOWN = CHANNEL_UNKNOWN
+
+    def get_CCCH(self):
+        return self.CCCH
+
+    def set_CCCH(self, CCCH):
+        self.CCCH = CCCH
+
+    def get_BCCH(self):
+        return self.BCCH
+
+    def set_BCCH(self, BCCH):
+        self.BCCH = BCCH
+
+    def get_AGCH(self):
+        return self.AGCH
+
+    def set_AGCH(self, AGCH):
+        self.AGCH = AGCH
+
+if __name__ == '__main__':
+    parser = OptionParser(option_class=eng_option, usage="%prog: [options]")
+    parser.add_option("-i", "--input-file-name", dest="input_file_name", type="string", default="input.cfile",
+        help="Set input.cfile [default=%default]")
+    parser.add_option("-f", "--fc", dest="fc", type="eng_float", default=eng_notation.num_to_str(937e6),
+        help="Set fc [default=%default]")
+    parser.add_option("-s", "--samp-rate", dest="samp_rate", type="eng_float", default=eng_notation.num_to_str(1e6),
+        help="Set samp_rate [default=%default]")
+    (options, args) = parser.parse_args()
+    tb = airprobe_file(input_file_name=options.input_file_name, fc=options.fc, samp_rate=options.samp_rate)
+    tb.start()
+    tb.wait()
diff --git a/apps/airprobe_rtlsdr.py b/apps/airprobe_rtlsdr.py
new file mode 100755
index 0000000..e6d0c35
--- /dev/null
+++ b/apps/airprobe_rtlsdr.py
@@ -0,0 +1,322 @@
+#!/usr/bin/env python
+##################################################
+# Gnuradio Python Flow Graph
+# Title: Airprobe Rtlsdr
+# Generated: Fri Nov 28 23:34:23 2014
+##################################################
+
+from PyQt4 import Qt
+from PyQt4.QtCore import QObject, pyqtSlot
+from gnuradio import blocks
+from gnuradio import eng_notation
+from gnuradio import gr
+from gnuradio import qtgui
+from gnuradio.eng_option import eng_option
+from gnuradio.filter import firdes
+from optparse import OptionParser
+import PyQt4.Qwt5 as Qwt
+import gsm
+import osmosdr
+import sip
+import sys
+
+from distutils.version import StrictVersion
+class airprobe_rtlsdr(gr.top_block, Qt.QWidget):
+
+    def __init__(self, ppm_param=0):
+        gr.top_block.__init__(self, "Airprobe Rtlsdr")
+        Qt.QWidget.__init__(self)
+        self.setWindowTitle("Airprobe Rtlsdr")
+        try:
+             self.setWindowIcon(Qt.QIcon.fromTheme('gnuradio-grc'))
+        except:
+             pass
+        self.top_scroll_layout = Qt.QVBoxLayout()
+        self.setLayout(self.top_scroll_layout)
+        self.top_scroll = Qt.QScrollArea()
+        self.top_scroll.setFrameStyle(Qt.QFrame.NoFrame)
+        self.top_scroll_layout.addWidget(self.top_scroll)
+        self.top_scroll.setWidgetResizable(True)
+        self.top_widget = Qt.QWidget()
+        self.top_scroll.setWidget(self.top_widget)
+        self.top_layout = Qt.QVBoxLayout(self.top_widget)
+        self.top_grid_layout = Qt.QGridLayout()
+        self.top_layout.addLayout(self.top_grid_layout)
+
+        self.settings = Qt.QSettings("GNU Radio", "airprobe_rtlsdr")
+        self.restoreGeometry(self.settings.value("geometry").toByteArray())
+
+
+        ##################################################
+        # Parameters
+        ##################################################
+        self.ppm_param = ppm_param
+
+        ##################################################
+        # Variables
+        ##################################################
+        self.samp_rate = samp_rate =  1500000.014901
+        self.ppm = ppm = ppm_param
+        self.g = g = 43
+        self.fc = fc = 939.4e6
+        self.SDCCH = SDCCH = 6
+        self.RACH = RACH = 3
+        self.PCH = PCH = 5
+        self.CHANNEL_UNKNOWN = CHANNEL_UNKNOWN = 0
+        self.CCCH = CCCH = 2
+        self.BCCH = BCCH = 1
+        self.AGCH = AGCH = 4
+
+        ##################################################
+        # Blocks
+        ##################################################
+        self._ppm_layout = Qt.QHBoxLayout()
+        self._ppm_layout.addWidget(Qt.QLabel("clock_correction [ppm]"+": "))
+        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(-100, 100, 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"+": "))
+        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("center_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.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_dc_offset_mode(0, 0)
+        self.rtlsdr_source_0.set_iq_balance_mode(0, 0)
+        self.rtlsdr_source_0.set_gain_mode(True, 0)
+        self.rtlsdr_source_0.set_gain(g, 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)
+        self.rtlsdr_source_0.set_bandwidth(250e3, 0)
+          
+        self.qtgui_freq_sink_x_0 = qtgui.freq_sink_c(
+        	1024, #size
+        	firdes.WIN_BLACKMAN_hARRIS, #wintype
+        	fc, #fc
+        	samp_rate, #bw
+        	"", #name
+        	1 #number of inputs
+        )
+        self.qtgui_freq_sink_x_0.set_update_time(0.10)
+        self.qtgui_freq_sink_x_0.set_y_axis(-140, 10)
+        self.qtgui_freq_sink_x_0.set_trigger_mode(qtgui.TRIG_MODE_FREE, 0.0, 0, "")
+        self.qtgui_freq_sink_x_0.enable_autoscale(False)
+        self.qtgui_freq_sink_x_0.enable_grid(False)
+        self.qtgui_freq_sink_x_0.set_fft_average(1.0)
+        
+        if complex == type(float()):
+          self.qtgui_freq_sink_x_0.set_plot_pos_half(not True)
+        
+        labels = ["", "", "", "", "",
+                  "", "", "", "", ""]
+        widths = [1, 1, 1, 1, 1,
+                  1, 1, 1, 1, 1]
+        colors = ["blue", "red", "green", "black", "cyan",
+                  "magenta", "yellow", "dark red", "dark green", "dark blue"]
+        alphas = [1.0, 1.0, 1.0, 1.0, 1.0,
+                  1.0, 1.0, 1.0, 1.0, 1.0]
+        for i in xrange(1):
+            if len(labels[i]) == 0:
+                self.qtgui_freq_sink_x_0.set_line_label(i, "Data {0}".format(i))
+            else:
+                self.qtgui_freq_sink_x_0.set_line_label(i, labels[i])
+            self.qtgui_freq_sink_x_0.set_line_width(i, widths[i])
+            self.qtgui_freq_sink_x_0.set_line_color(i, colors[i])
+            self.qtgui_freq_sink_x_0.set_line_alpha(i, alphas[i])
+        
+        self._qtgui_freq_sink_x_0_win = sip.wrapinstance(self.qtgui_freq_sink_x_0.pyqwidget(), Qt.QWidget)
+        self.top_layout.addWidget(self._qtgui_freq_sink_x_0_win)
+        self.gsm_universal_ctrl_chans_demapper_0 = gsm.universal_ctrl_chans_demapper(([2,6,12,16,22,26,32,36,42,46]), ([BCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH,CCCH]))
+        self.gsm_receiver_0 = gsm.receiver(4, ([0]), ([]))
+        self.gsm_message_printer_1 = gsm.message_printer()
+        self.gsm_input_0 = gsm.gsm_input(
+            ppm=0,
+            osr=4,
+            fc=fc,
+            samp_rate_in=samp_rate,
+        )
+        self.gsm_control_channels_decoder_0 = gsm.control_channels_decoder()
+        self.gsm_clock_offset_control_0 = gsm.clock_offset_control(fc)
+        self.blocks_socket_pdu_0 = blocks.socket_pdu("UDP_CLIENT", "127.0.0.1", "4729", 10000, False)
+
+        ##################################################
+        # Connections
+        ##################################################
+        self.connect((self.rtlsdr_source_0, 0), (self.qtgui_freq_sink_x_0, 0))
+        self.connect((self.rtlsdr_source_0, 0), (self.gsm_input_0, 0))
+        self.connect((self.gsm_input_0, 0), (self.gsm_receiver_0, 0))
+
+        ##################################################
+        # Asynch Message Connections
+        ##################################################
+        self.msg_connect(self.gsm_clock_offset_control_0, "ppm", self.gsm_input_0, "ppm_in")
+        self.msg_connect(self.gsm_receiver_0, "C0", self.gsm_universal_ctrl_chans_demapper_0, "bursts")
+        self.msg_connect(self.gsm_control_channels_decoder_0, "msgs", self.gsm_message_printer_1, "msgs")
+        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, "measurements", self.gsm_clock_offset_control_0, "measurements")
+
+    def closeEvent(self, event):
+        self.settings = Qt.QSettings("GNU Radio", "airprobe_rtlsdr")
+        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.qtgui_freq_sink_x_0.set_frequency_range(self.fc, self.samp_rate)
+        self.gsm_input_0.set_samp_rate_in(self.samp_rate)
+        self.rtlsdr_source_0.set_sample_rate(self.samp_rate)
+
+    def get_ppm(self):
+        return self.ppm
+
+    def set_ppm(self, ppm):
+        self.ppm = ppm
+        Qt.QMetaObject.invokeMethod(self._ppm_counter, "setValue", Qt.Q_ARG("double", self.ppm))
+        self.rtlsdr_source_0.set_freq_corr(self.ppm, 0)
+
+    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)
+
+    def get_fc(self):
+        return self.fc
+
+    def set_fc(self, fc):
+        self.fc = fc
+        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.qtgui_freq_sink_x_0.set_frequency_range(self.fc, self.samp_rate)
+        self.gsm_input_0.set_fc(self.fc)
+        self.rtlsdr_source_0.set_center_freq(self.fc, 0)
+
+    def get_SDCCH(self):
+        return self.SDCCH
+
+    def set_SDCCH(self, SDCCH):
+        self.SDCCH = SDCCH
+
+    def get_RACH(self):
+        return self.RACH
+
+    def set_RACH(self, RACH):
+        self.RACH = RACH
+
+    def get_PCH(self):
+        return self.PCH
+
+    def set_PCH(self, PCH):
+        self.PCH = PCH
+
+    def get_CHANNEL_UNKNOWN(self):
+        return self.CHANNEL_UNKNOWN
+
+    def set_CHANNEL_UNKNOWN(self, CHANNEL_UNKNOWN):
+        self.CHANNEL_UNKNOWN = CHANNEL_UNKNOWN
+
+    def get_CCCH(self):
+        return self.CCCH
+
+    def set_CCCH(self, CCCH):
+        self.CCCH = CCCH
+
+    def get_BCCH(self):
+        return self.BCCH
+
+    def set_BCCH(self, BCCH):
+        self.BCCH = BCCH
+
+    def get_AGCH(self):
+        return self.AGCH
+
+    def set_AGCH(self, AGCH):
+        self.AGCH = AGCH
+
+if __name__ == '__main__':
+    import ctypes
+    import sys
+    if sys.platform.startswith('linux'):
+        try:
+            x11 = ctypes.cdll.LoadLibrary('libX11.so')
+            x11.XInitThreads()
+        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,
+        help="Set ppm [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.start()
+    tb.show()
+    def quitting():
+        tb.stop()
+        tb.wait()
+    qapp.connect(qapp, Qt.SIGNAL("aboutToQuit()"), quitting)
+    qapp.exec_()
+    tb = None #to clean up Qt widgets