diff --git a/apps/osmocom_fft b/apps/osmocom_fft
index a346b2a..c087f6e 100755
--- a/apps/osmocom_fft
+++ b/apps/osmocom_fft
@@ -97,6 +97,12 @@ class app_top_block(stdgui2.std_top_block, pubsub):
 
         self.src = osmosdr.source(options.args)
 
+        try:
+            self.src.get_sample_rates().start()
+        except RuntimeError:
+            print "Source has no sample rates (wrong device arguments?)."
+            sys.exit(1)
+
         # Set the antenna
         if(options.antenna):
             self.src.set_antenna(options.antenna)
diff --git a/apps/osmocom_siggen_base.py b/apps/osmocom_siggen_base.py
index c32388c..50d6d66 100644
--- a/apps/osmocom_siggen_base.py
+++ b/apps/osmocom_siggen_base.py
@@ -160,6 +160,12 @@ class top_block(gr.top_block, pubsub):
     def _setup_osmosdr(self, options):
         self._sink = osmosdr.sink(options.args)
 
+        try:
+            self._sink.get_sample_rates().start()
+        except RuntimeError:
+            print "Sink has no sample rates (wrong device arguments?)."
+            sys.exit(1)
+
         if options.samp_rate is None:
             options.samp_rate = self._sink.get_sample_rates().start()
 
diff --git a/apps/osmocom_spectrum_sense b/apps/osmocom_spectrum_sense
index 71e14aa..ea365bb 100755
--- a/apps/osmocom_spectrum_sense
+++ b/apps/osmocom_spectrum_sense
@@ -21,8 +21,11 @@
 #
 
 import osmosdr
-from gnuradio import gr, eng_notation, window
+from gnuradio import gr, eng_notation
+from gnuradio import blocks
 from gnuradio import audio
+from gnuradio import filter
+from gnuradio import fft
 from gnuradio.eng_option import eng_option
 from optparse import OptionParser
 import sys
@@ -47,7 +50,7 @@ class tune(gr.feval_dd):
 
     def eval(self, ignore):
         """
-        This method is called from gr.bin_statistics_f when it wants
+        This method is called from blocks.bin_statistics_f when it wants
         to change the center frequency.  This method tunes the front
         end to the new center frequency, and returns the new frequency
         as its result.
@@ -149,6 +152,12 @@ class my_top_block(gr.top_block):
         # build graph
         self.u = osmosdr.source(options.args)
 
+        try:
+            self.u.get_sample_rates().start()
+        except RuntimeError:
+            print "Source has no sample rates (wrong device arguments?)."
+            sys.exit(1)
+
         # Set the antenna
         if(options.antenna):
             self.u.set_antenna(options.antenna, 0)
@@ -166,19 +175,19 @@ class my_top_block(gr.top_block):
         
         self.squelch_threshold = options.squelch_threshold
         
-        s2v = gr.stream_to_vector(gr.sizeof_gr_complex, self.fft_size)
+        s2v = blocks.stream_to_vector(gr.sizeof_gr_complex, self.fft_size)
 
-        mywindow = window.blackmanharris(self.fft_size)
-        fft = gr.fft_vcc(self.fft_size, True, mywindow, True)
+        mywindow = filter.window.blackmanharris(self.fft_size)
+        ffter = fft.fft_vcc(self.fft_size, True, mywindow, True)
         power = 0
         for tap in mywindow:
             power += tap*tap
 
-        c2mag = gr.complex_to_mag_squared(self.fft_size)
+        c2mag = blocks.complex_to_mag_squared(self.fft_size)
 
         # FIXME the log10 primitive is dog slow
-        #log = gr.nlog10_ff(10, self.fft_size,
-        #                   -20*math.log10(self.fft_size)-10*math.log10(power/self.fft_size))
+        #log = blocks.nlog10_ff(10, self.fft_size,
+        #                       -20*math.log10(self.fft_size)-10*math.log10(power/self.fft_size))
 
         # Set the freq_step to 75% of the actual data throughput.
         # This allows us to discard the bins on both ends of the spectrum.
@@ -195,13 +204,13 @@ class my_top_block(gr.top_block):
 
         self.msgq = gr.msg_queue(1)
         self._tune_callback = tune(self)        # hang on to this to keep it from being GC'd
-        stats = gr.bin_statistics_f(self.fft_size, self.msgq,
-                                    self._tune_callback, tune_delay,
-                                    dwell_delay)
+        stats = blocks.bin_statistics_f(self.fft_size, self.msgq,
+                                        self._tune_callback, tune_delay,
+                                        dwell_delay)
 
         # FIXME leave out the log10 until we speed it up
-        #self.connect(self.u, s2v, fft, c2mag, log, stats)
-        self.connect(self.u, s2v, fft, c2mag, stats)
+        #self.connect(self.u, s2v, ffter, c2mag, log, stats)
+        self.connect(self.u, s2v, ffter, c2mag, stats)
 
         if options.gain is None:
             # if no gain was specified, use the mid-point in dB