diff --git a/background.npy b/background.npy
index c3d18da..b5c57ef 100644
Binary files a/background.npy and b/background.npy differ
diff --git a/rfg_adc_plotter/gui/matplotlib_backend.py b/rfg_adc_plotter/gui/matplotlib_backend.py
index b936a22..19e859a 100644
--- a/rfg_adc_plotter/gui/matplotlib_backend.py
+++ b/rfg_adc_plotter/gui/matplotlib_backend.py
@@ -268,7 +268,15 @@ def run_matplotlib(args):
                 m = float(np.nanmax(np.abs(data)))
                 return data / m if m > 0.0 else data
             line_obj.set_data(xs, _norm_to_max(raw))
-            if state.last_calib_sweep is not None:
+            if state.calib_mode == "file" and state.calib_file_envelope is not None:
+                upper = state.calib_file_envelope
+                lower = -upper
+                m_env = float(np.nanmax(np.abs(upper)))
+                if m_env <= 0.0:
+                    m_env = 1.0
+                line_env_lo.set_data(xs[: upper.size], lower / m_env)
+                line_env_hi.set_data(xs[: upper.size], upper / m_env)
+            elif state.last_calib_sweep is not None:
                 calib = state.last_calib_sweep
                 m_calib = float(np.nanmax(np.abs(calib)))
                 if m_calib <= 0.0:
diff --git a/rfg_adc_plotter/gui/pyqtgraph_backend.py b/rfg_adc_plotter/gui/pyqtgraph_backend.py
index 97aa872..9ac4174 100644
--- a/rfg_adc_plotter/gui/pyqtgraph_backend.py
+++ b/rfg_adc_plotter/gui/pyqtgraph_backend.py
@@ -290,7 +290,15 @@ def run_pyqtgraph(args):
                 m = float(np.nanmax(np.abs(data)))
                 return data / m if m > 0.0 else data
             curve.setData(xs, _norm_to_max(raw), autoDownsample=True)
-            if state.last_calib_sweep is not None:
+            if state.calib_mode == "file" and state.calib_file_envelope is not None:
+                upper = state.calib_file_envelope
+                lower = -upper
+                m_env = float(np.nanmax(np.abs(upper)))
+                if m_env <= 0.0:
+                    m_env = 1.0
+                curve_env_lo.setData(xs[: upper.size], lower / m_env, autoDownsample=True)
+                curve_env_hi.setData(xs[: upper.size], upper / m_env, autoDownsample=True)
+            elif state.last_calib_sweep is not None:
                 calib = state.last_calib_sweep
                 m_calib = float(np.nanmax(np.abs(calib)))
                 if m_calib <= 0.0: