diff --git a/rfg_vna_viewer.py b/rfg_vna_viewer.py
index 4917745..7489e64 100644
--- a/rfg_vna_viewer.py
+++ b/rfg_vna_viewer.py
@@ -283,14 +283,40 @@ def make_update(reader, parser, assembler, curves, plots):
         fft_db = 20.0 * np.log10(fft_mag + 1e-12)
         c_fft.setData(fft_dist, fft_db)
 
-        # Lock axes after first sweep — freeze current Y ranges
+        # Lock axes after first sweep — compute ranges from data, then freeze
         if not state["axes_locked"]:
             state["axes_locked"] = True
-            for p in plots:
-                vr = p.viewRange()
-                p.disableAutoRange()
-                p.setXRange(vr[0][0], vr[0][1], padding=0)
-                p.setYRange(vr[1][0], vr[1][1], padding=0)
+            p_raw, p_ch, p_norm, p_ph, p_fft = plots
+
+            fx0, fx1 = freqs_ghz[0], freqs_ghz[-1]
+
+            # Row 0: raw amplitudes
+            y_all = np.concatenate([main_amp, ref_amplitude])
+            p_raw.disableAutoRange()
+            p_raw.setXRange(fx0, fx1, padding=0)
+            p_raw.setYRange(float(y_all.min()), float(y_all.max()), padding=0.05)
+
+            # Row 1: normalized ch1/ch2
+            y_all = np.concatenate([norm_ch1, norm_ch2])
+            p_ch.disableAutoRange()
+            p_ch.setXRange(fx0, fx1, padding=0)
+            p_ch.setYRange(float(y_all.min()), float(y_all.max()), padding=0.05)
+
+            # Row 2: normalized amplitude
+            p_norm.disableAutoRange()
+            p_norm.setXRange(fx0, fx1, padding=0)
+            p_norm.setYRange(float(norm_amp.min()), float(norm_amp.max()), padding=0.05)
+
+            # Row 3: phase + line + deviation
+            y_all = np.concatenate([phase, line, deviation])
+            p_ph.disableAutoRange()
+            p_ph.setXRange(fx0, fx1, padding=0)
+            p_ph.setYRange(float(y_all.min()), float(y_all.max()), padding=0.05)
+
+            # Row 4: FFT
+            p_fft.disableAutoRange()
+            p_fft.setXRange(float(fft_dist[0]), float(fft_dist[-1]), padding=0)
+            p_fft.setYRange(float(fft_db.min()), float(fft_db.max()), padding=0.05)
 
     return update