diff --git a/charon_vna/vna.py b/charon_vna/vna.py
index d1c77b8..0a6bcf5 100644
--- a/charon_vna/vna.py
+++ b/charon_vna/vna.py
@@ -18,6 +18,20 @@ dir_ = Path(__file__).parent
 
 
 # %% connection
+
+
+def generate_tone(f: float, fs: float, N: int = 1024, scale: int = 2**14):
+    fs = int(fs)
+    fc = int(f / (fs / N)) * (fs / N)
+    ts = 1 / float(fs)
+    t = np.arange(0, N * ts, ts)
+    i = np.cos(2 * np.pi * t * fc) * scale
+    q = np.sin(2 * np.pi * t * fc) * scale
+    iq = i + 1j * q
+
+    return iq
+
+
 class Charon:
     FREQUENCY_OFFSET = 1e6
 
@@ -58,19 +72,19 @@ class Charon:
         self.sdr.loopback = 0
         self.sdr.gain_control_mode_chan0 = "manual"
         self.sdr.gain_control_mode_chan1 = "manual"
-        self.sdr.rx_hardwaregain_chan0 = 40
-        self.sdr.rx_hardwaregain_chan1 = 40
+        self.sdr.rx_hardwaregain_chan0 = 10
+        self.sdr.rx_hardwaregain_chan1 = 10
         self.sdr.tx_hardwaregain_chan0 = -10
 
-        # switch control
-        ctx = iio.Context(uri)
-        self.ctrl = ctx.find_device("ad9361-phy")
-        # raw ad9361 register accesss:
-        # https://ez.analog.com/linux-software-drivers/f/q-a/120853/control-fmcomms3-s-gpo-with-python
-        # https://www.analog.com/media/cn/technical-documentation/user-guides/ad9364_register_map_reference_manual_ug-672.pdf
-        self.ctrl.reg_write(0x26, 0x90)  # bit 7: AuxDAC Manual, bit 4: GPO Manual
-        self._set_gpo(self.ports[0] - 1)
-        # TODO: init AuxDAC
+        # # switch control
+        # ctx = iio.Context(uri)
+        # self.ctrl = ctx.find_device("ad9361-phy")
+        # # raw ad9361 register accesss:
+        # # https://ez.analog.com/linux-software-drivers/f/q-a/120853/control-fmcomms3-s-gpo-with-python
+        # # https://www.analog.com/media/cn/technical-documentation/user-guides/ad9364_register_map_reference_manual_ug-672.pdf
+        # self.ctrl.reg_write(0x26, 0x90)  # bit 7: AuxDAC Manual, bit 4: GPO Manual
+        # self._set_gpo(self.ports[0] - 1)
+        # # TODO: init AuxDAC
 
     def get_config(self) -> Dict[str, Any]:
         config = dict()
@@ -119,17 +133,6 @@ class Charon:
             # tx_gain = pout.coords["tx_gain"][tx_gain_idx]
         self.sdr.tx_hardwaregain_chan0 = float(tx_gain)
 
-    def generate_tone(self, f: float, fs: float, N: int = 1024, scale: int = 2**14):
-        fs = int(fs)
-        fc = int(f / (fs / N)) * (fs / N)
-        ts = 1 / float(fs)
-        t = np.arange(0, N * ts, ts)
-        i = np.cos(2 * np.pi * t * fc) * scale
-        q = np.sin(2 * np.pi * t * fc) * scale
-        iq = i + 1j * q
-
-        return iq
-
     def set_output(self, frequency: float, power: float):
         # TODO: switch to DDS in Pluto
 
@@ -137,7 +140,7 @@ class Charon:
         self.set_output_power(power)
         self.sdr.tx_lo = int(frequency - self.FREQUENCY_OFFSET)
         self.sdr.tx_cyclic_buffer = True
-        # self.sdr.tx(self.generate_tone(f=self.FREQUENCY_OFFSET, fs=self.sdr.sample_rate))
+        # self.sdr.tx(generate_tone(f=self.FREQUENCY_OFFSET, fs=self.sdr.sample_rate))
         self.sdr.dds_single_tone(self.FREQUENCY_OFFSET, scale=0.9, channel=0)
 
     def _rx(self, count: int = 1, fc: float | None = None) -> npt.ArrayLike:
@@ -158,7 +161,7 @@ class Charon:
         self.set_output(frequency=frequency, power=-5)
 
         data = self._rx(1, fc=frequency - self.FREQUENCY_OFFSET)
-        ddc_tone = self.generate_tone(f=-self.FREQUENCY_OFFSET, fs=self.sdr.sample_rate, scale=1)
+        ddc_tone = generate_tone(f=-self.FREQUENCY_OFFSET, fs=self.sdr.sample_rate, scale=1)
         ddc_data = data * ddc_tone
 
         ddc_rel = ddc_data[1] / ddc_data[0]
@@ -202,14 +205,36 @@ class Charon:
             s.loc[dict(frequency=frequency)] = self.get_b_over_a(frequency=frequency)
         return s
 
+    def vna_capture(self, frequency: npt.ArrayLike):
+        s = xr.DataArray(
+            np.empty(len(frequency), dtype=np.complex128),
+            dims=["frequency"],
+            coords=dict(
+                frequency=frequency,
+            ),
+        )
+        for freq in s.frequency.data:
+            self.set_output(frequency=freq, power=-5)
+            self.sdr.rx_destroy_buffer()
+            self.sdr.rx_lo = int(freq)
+            self.sdr.rx_enabled_channels = [0, 1]
+            self.sdr.gain_control_mode_chan0 = "manual"
+            self.sdr.gain_control_mode_chan1 = "manual"
+            self.sdr.rx_hardwaregain_chan0 = 40
+            self.sdr.rx_hardwaregain_chan1 = 40
+            rx = self.sdr.rx()
+            s.loc[dict(frequency=freq)] = np.mean(rx[1] / rx[0])
+
+        return s
+
 
 # %%
 sdr = Charon("ip:192.168.3.1", frequency=np.linspace(1e9, 1.1e9, 11))
 
 # %% initialization
 config = sdr.get_config()
-print(sdr.ctrl.debug_attrs["adi,rx-rf-port-input-select"].value)
-print(sdr.ctrl.debug_attrs["adi,tx-rf-port-input-select"].value)
+# print(sdr.ctrl.debug_attrs["adi,rx-rf-port-input-select"].value)
+# print(sdr.ctrl.debug_attrs["adi,tx-rf-port-input-select"].value)
 config
 
 # %% generate tone
@@ -264,31 +289,7 @@ plt.show()
 
 
 # %%
-def vna_capture(frequency: npt.ArrayLike):
-    s = xr.DataArray(
-        np.empty(len(frequency), dtype=np.complex128),
-        dims=["frequency"],
-        coords=dict(
-            frequency=frequency,
-        ),
-    )
-    for freq in s.frequency.data:
-        set_output(frequency=freq, power=-5)
-        sdr.rx_destroy_buffer()
-        sdr.rx_lo = int(freq)
-        sdr.rx_enabled_channels = [0, 1]
-        sdr.gain_control_mode_chan0 = "manual"
-        sdr.gain_control_mode_chan1 = "manual"
-        sdr.rx_hardwaregain_chan0 = 40
-        sdr.rx_hardwaregain_chan1 = 40
-        rx = sdr.rx()
-        s.loc[dict(frequency=freq)] = np.mean(rx[1] / rx[0])
-
-    return s
-
-
-# %%
-s = vna_capture(frequency=np.linspace(70e6, 200e6, 101))
+s = sdr.vna_capture(frequency=np.linspace(70e6, 200e6, 101))
 
 # %% Plot Logmag
 fig, axs = plt.subplots(2, 1, sharex=True, tight_layout=True)