diff --git a/gamutrf/grscan.py b/gamutrf/grscan.py
index bf8cd97c..63c3d9ed 100644
--- a/gamutrf/grscan.py
+++ b/gamutrf/grscan.py
@@ -73,9 +73,7 @@ def __init__(
         self.wavelearner = wavelearner
         self.iqtlabs = iqtlabs
         self.samp_rate = samp_rate
-        self.retune_pre_fft = blocks.stream_to_vector(
-            gr.sizeof_gr_complex, fft_batch_size * nfft
-        )
+        self.retune_pre_fft = None
 
         ##################################################
         # Blocks
@@ -335,6 +333,20 @@ def get_fft_blocks(
         tuning_ranges,
         pretune,
     ):
+        fft_block = None
+        fft_roll = False
+        if self.wavelearner:
+            fft_block = self.wavelearner.fft(int(fft_batch_size * nfft), (nfft), True)
+            fft_roll = True
+        elif vkfft:
+            fft_block = self.iqtlabs.vkfft(int(fft_batch_size * nfft), nfft, True)
+        else:
+            fft_batch_size = 1
+
+        fft_blocks = []
+        if dc_block_len:
+            fft_blocks.append(grfilter.dc_blocker_cc(dc_block_len, dc_block_long))
+
         if pretune:
             self.retune_pre_fft = self.iqtlabs.retune_pre_fft(
                 nfft,
@@ -347,16 +359,11 @@ def get_fft_blocks(
                 skip_tune_step,
                 tuning_ranges,
             )
-        fft_blocks = []
-        if dc_block_len:
-            fft_blocks.append(grfilter.dc_blocker_cc(dc_block_len, dc_block_long))
-        fft_block = None
-        fft_roll = False
-        if self.wavelearner:
-            fft_block = self.wavelearner.fft(int(fft_batch_size * nfft), (nfft), True)
-            fft_roll = True
-        elif vkfft:
-            fft_block = self.iqtlabs.vkfft(int(fft_batch_size * nfft), nfft, True)
+        else:
+            self.retune_pre_fft = blocks.stream_to_vector(
+                gr.sizeof_gr_complex, fft_batch_size * nfft
+            )
+
         if fft_block:
             fft_blocks.extend(
                 self.get_offload_fft_block(
diff --git a/tests/test_grscan.py b/tests/test_grscan.py
index a102dccd..83e30c47 100644
--- a/tests/test_grscan.py
+++ b/tests/test_grscan.py
@@ -107,7 +107,7 @@ def run_grscan_smoke(self, pretune, wavelearner, write_samples):
                 rotate_secs=900,
                 db_clamp_floor=-1e6,
                 pretune=pretune,
-                fft_batch_size=1,
+                fft_batch_size=256,
             )
             tb.start()
             time.sleep(3)