diff --git a/apps/airprobe_rtlsdr.py b/apps/airprobe_rtlsdr.py
new file mode 100755
index 0000000..17cb1d3
--- /dev/null
+++ b/apps/airprobe_rtlsdr.py
@@ -0,0 +1,275 @@
+#!/usr/bin/env python2
+##################################################
+# GNU Radio Python Flow Graph
+# Title: Airprobe Rtlsdr
+# Generated: Wed Sep  2 21:46:35 2015
+##################################################
+
+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()"
+
+from PyQt4 import Qt
+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 gnuradio.qtgui import Range, RangeWidget
+from math import pi
+from optparse import OptionParser
+import grgsm
+import osmosdr
+import pmt
+import sip
+import sys
+import time
+
+
+class airprobe_rtlsdr(gr.top_block, Qt.QWidget):
+
+    def __init__(self, fc=939.4e6, gain=30, ppm=0, samp_rate=2000000.052982, shiftoff=400e3):
+        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.fc = fc
+        self.gain = gain
+        self.ppm = ppm
+        self.samp_rate = samp_rate
+        self.shiftoff = shiftoff
+
+        ##################################################
+        # Variables
+        ##################################################
+        self.ppm_slider = ppm_slider = ppm
+        self.g_slider = g_slider = gain
+        self.fc_slider = fc_slider = fc
+
+        ##################################################
+        # Blocks
+        ##################################################
+        self._ppm_slider_range = Range(-150, 150, 1, ppm, 100)
+        self._ppm_slider_win = RangeWidget(self._ppm_slider_range, self.set_ppm_slider, "PPM Offset", "counter", float)
+        self.top_layout.addWidget(self._ppm_slider_win)
+        self._g_slider_range = Range(0, 50, 0.5, gain, 100)
+        self._g_slider_win = RangeWidget(self._g_slider_range, self.set_g_slider, "Gain", "counter", float)
+        self.top_layout.addWidget(self._g_slider_win)
+        self._fc_slider_range = Range(925e6, 1990e6, 2e5, fc, 100)
+        self._fc_slider_win = RangeWidget(self._fc_slider_range, self.set_fc_slider, "Frequency", "counter_slider", float)
+        self.top_layout.addWidget(self._fc_slider_win)
+        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_slider-shiftoff, 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(False, 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)
+        self.rtlsdr_source_0.set_bandwidth(250e3+abs(shiftoff), 0)
+          
+        self.qtgui_freq_sink_x_0 = qtgui.freq_sink_c(
+        	1024, #size
+        	firdes.WIN_BLACKMAN_hARRIS, #wintype
+        	fc_slider, #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)
+        self.qtgui_freq_sink_x_0.enable_control_panel(False)
+        
+        if not True:
+          self.qtgui_freq_sink_x_0.disable_legend()
+        
+        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_sdcch8_demapper_0 = grgsm.universal_ctrl_chans_demapper(1, ([0,4,8,12,16,20,24,28,32,36,40,44]), ([8,8,8,8,8,8,8,8,136,136,136,136]))
+        self.gsm_receiver_0 = grgsm.receiver(4, ([0]), ([]))
+        self.gsm_message_printer_1 = grgsm.message_printer(pmt.intern(""), False)
+        self.gsm_input_0 = grgsm.gsm_input(
+            ppm=0,
+            osr=4,
+            fc=fc,
+            samp_rate_in=samp_rate,
+        )
+        self.gsm_decryption_0 = grgsm.decryption(([]), 1)
+        self.gsm_control_channels_decoder_0_0 = grgsm.control_channels_decoder()
+        self.gsm_control_channels_decoder_0 = grgsm.control_channels_decoder()
+        self.gsm_clock_offset_control_0 = grgsm.clock_offset_control(fc-shiftoff)
+        self.gsm_bcch_ccch_demapper_0 = grgsm.universal_ctrl_chans_demapper(0, ([2,6,12,16,22,26,32,36,42,46]), ([1,2,2,2,2,2,2,2,2,2]))
+        self.blocks_socket_pdu_0_0 = blocks.socket_pdu("UDP_SERVER", "127.0.0.1", "4729", 10000, False)
+        self.blocks_socket_pdu_0 = blocks.socket_pdu("UDP_CLIENT", "127.0.0.1", "4729", 10000, False)
+        self.blocks_rotator_cc_0 = blocks.rotator_cc(-2*pi*shiftoff/samp_rate)
+
+        ##################################################
+        # Connections
+        ##################################################
+        self.msg_connect((self.gsm_bcch_ccch_demapper_0, 'bursts'), (self.gsm_control_channels_decoder_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'))    
+        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_0, 'msgs'), (self.blocks_socket_pdu_0, 'pdus'))    
+        self.msg_connect((self.gsm_control_channels_decoder_0_0, 'msgs'), (self.gsm_message_printer_1, 'msgs'))    
+        self.msg_connect((self.gsm_decryption_0, 'bursts'), (self.gsm_control_channels_decoder_0_0, 'bursts'))    
+        self.msg_connect((self.gsm_receiver_0, 'C0'), (self.gsm_bcch_ccch_demapper_0, 'bursts'))    
+        self.msg_connect((self.gsm_receiver_0, 'measurements'), (self.gsm_clock_offset_control_0, 'measurements'))    
+        self.msg_connect((self.gsm_receiver_0, 'C0'), (self.gsm_sdcch8_demapper_0, 'bursts'))    
+        self.msg_connect((self.gsm_sdcch8_demapper_0, 'bursts'), (self.gsm_decryption_0, 'bursts'))    
+        self.connect((self.blocks_rotator_cc_0, 0), (self.gsm_input_0, 0))    
+        self.connect((self.blocks_rotator_cc_0, 0), (self.qtgui_freq_sink_x_0, 0))    
+        self.connect((self.gsm_input_0, 0), (self.gsm_receiver_0, 0))    
+        self.connect((self.rtlsdr_source_0, 0), (self.blocks_rotator_cc_0, 0))    
+
+    def closeEvent(self, event):
+        self.settings = Qt.QSettings("GNU Radio", "airprobe_rtlsdr")
+        self.settings.setValue("geometry", self.saveGeometry())
+        event.accept()
+
+    def get_fc(self):
+        return self.fc
+
+    def set_fc(self, fc):
+        self.fc = fc
+        self.set_fc_slider(self.fc)
+        self.gsm_input_0.set_fc(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_ppm(self):
+        return self.ppm
+
+    def set_ppm(self, ppm):
+        self.ppm = ppm
+        self.set_ppm_slider(self.ppm)
+
+    def get_samp_rate(self):
+        return self.samp_rate
+
+    def set_samp_rate(self, samp_rate):
+        self.samp_rate = samp_rate
+        self.blocks_rotator_cc_0.set_phase_inc(-2*pi*self.shiftoff/self.samp_rate)
+        self.gsm_input_0.set_samp_rate_in(self.samp_rate)
+        self.qtgui_freq_sink_x_0.set_frequency_range(self.fc_slider, self.samp_rate)
+        self.rtlsdr_source_0.set_sample_rate(self.samp_rate)
+
+    def get_shiftoff(self):
+        return self.shiftoff
+
+    def set_shiftoff(self, shiftoff):
+        self.shiftoff = shiftoff
+        self.blocks_rotator_cc_0.set_phase_inc(-2*pi*self.shiftoff/self.samp_rate)
+        self.rtlsdr_source_0.set_center_freq(self.fc_slider-self.shiftoff, 0)
+        self.rtlsdr_source_0.set_bandwidth(250e3+abs(self.shiftoff), 0)
+
+    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)
+
+    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)
+
+    def get_fc_slider(self):
+        return self.fc_slider
+
+    def set_fc_slider(self, fc_slider):
+        self.fc_slider = fc_slider
+        self.qtgui_freq_sink_x_0.set_frequency_range(self.fc_slider, self.samp_rate)
+        self.rtlsdr_source_0.set_center_freq(self.fc_slider-self.shiftoff, 0)
+
+
+if __name__ == '__main__':
+    parser = OptionParser(option_class=eng_option, usage="%prog: [options]")
+    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("-p", "--ppm", dest="ppm", type="intx", default=0,
+        help="Set ppm [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]")
+    parser.add_option("-o", "--shiftoff", dest="shiftoff", type="eng_float", default=eng_notation.num_to_str(400e3),
+        help="Set shiftoff [default=%default]")
+    (options, args) = parser.parse_args()
+    from distutils.version import StrictVersion
+    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(fc=options.fc, gain=options.gain, ppm=options.ppm, samp_rate=options.samp_rate, shiftoff=options.shiftoff)
+    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