diff --git a/charon_vna/gui.py b/charon_vna/gui.py
index e293037..a5cda73 100644
--- a/charon_vna/gui.py
+++ b/charon_vna/gui.py
@@ -24,7 +24,8 @@ from PySide6.QtWidgets import (
 )
 from skrf import plotting as rf_plt
 from util import db20, s2vswr
-from vna import Charon
+
+# from vna import Charon
 
 DEFAULT_CONFIG = dict(
     frequency=np.arange(1e9, 2e9, 11),  # Hz
@@ -61,9 +62,7 @@ class PlotWidget(QWidget):
         self.ax.xaxis.set_major_formatter(EngFormatter())
         self.ax.set_xlabel("Frequency [Hz]")
 
-    def update_rect(
-        self, data: xr.DataArray, func: Callable[[npt.ArrayLike[np.complex128]], npt.ArrayLike[float]]
-    ) -> None:
+    def update_rect(self, data: xr.DataArray, func: Callable[[npt.ArrayLike], npt.ArrayLike]) -> None:
         self.ax.set_xlim(data["frequency"].min().data, data["frequency"].max().data)
         # remove old lines
         for line in self.ax.lines:
@@ -115,14 +114,14 @@ class PlotWidget(QWidget):
 # Subclass QMainWindow to customize your application's main window
 class MainWindow(QMainWindow):
     config_path: Path | None
-    device: Charon
+    # device: Charon
 
     def __init__(self):
         super().__init__()
 
         self.config_path = None
 
-        self.device = Charon("ip:192.168.3.1", frequency=DEFAULT_CONFIG["frequency"])
+        # self.device = Charon("ip:192.168.3.1", frequency=DEFAULT_CONFIG["frequency"])
 
         mpl.use("QtAgg")
 
@@ -148,6 +147,12 @@ class MainWindow(QMainWindow):
 
         menu_stimulus = QMenu("&Stimulus")
         menubar.addMenu(menu_stimulus)
+        action_set_frequency = QAction("&Frequency", self)
+        menu_stimulus.addAction(action_set_frequency)
+        # action_set_frequency.triggered.connect(self.set_frequency)
+        action_set_power = QAction("&Power", self)
+        menu_stimulus.addAction(action_set_power)
+        # action_set_power.triggered.connect(self.set_power)
 
         menu_calibration = QMenu("&Calibration")
         menubar.addMenu(menu_calibration)
diff --git a/charon_vna/util.py b/charon_vna/util.py
index dff9dcd..249131a 100644
--- a/charon_vna/util.py
+++ b/charon_vna/util.py
@@ -38,15 +38,15 @@ HAM_BANDS = [
 ]
 
 
-def db10(p: npt.ArrayLike[np.complex128]) -> npt.ArrayLike[float]:
+def db10(p: npt.ArrayLike) -> npt.ArrayLike:
     return 10 * np.log10(np.abs(p))
 
 
-def db20(v: npt.ArrayLike[np.complex128]) -> npt.ArrayLike[float]:
+def db20(v: npt.ArrayLike) -> npt.ArrayLike:
     return 20 * np.log10(np.abs(v))
 
 
-def s2vswr(s: npt.ArrayLike[np.complex128]) -> npt.ArrayLike[float]:
+def s2vswr(s: npt.ArrayLike) -> npt.ArrayLike:
     return (1 + np.abs(s)) / (1 - np.abs(s))