diff --git a/charon_vna/vna.py b/charon_vna/vna.py
index 1cf54f5..3ea3552 100644
--- a/charon_vna/vna.py
+++ b/charon_vna/vna.py
@@ -2,7 +2,7 @@
 import copy
 from enum import IntEnum, unique
 from pathlib import Path
-from typing import Any, Callable, Dict, Literal, Tuple
+from typing import Any, Callable, Dict, List, Literal, Tuple
 
 import adi
 import iio
@@ -305,7 +305,16 @@ class Charon:
 
         return np.mean(data[1] / data[0])
 
-    def capture(self, callback: Callable[int, int] | None = None):
+    def capture(
+        self,
+        callback: Callable[int, int] | None = None,
+        *,
+        measurements: List[Tuple[int, int]] = None,
+    ):
+        if measurements is None:
+            measurements = [(m, n) for n in self.ports for m in self.ports]
+        measurements = list(measurements)
+
         s = xr.DataArray(
             np.zeros(
                 [len(self.frequency), len(self.ports), len(self.ports)],
@@ -319,30 +328,31 @@ class Charon:
             ),
         )
 
-        total_count = len(s.m) * len(s.n) * len(s.frequency)
+        total_count = len(measurements) * len(s.frequency)
         count = 0
 
         for m in s.m.data:
             for n in s.n.data:
-                self.set_switches(b=m - 1, a=n - 1)
+                if (m, n) in measurements:
+                    self.set_switches(b=m - 1, a=n - 1)
 
-                for ff, freq in enumerate(s.frequency.data):
-                    if callback is not None:
-                        # report progress during sweep
-                        callback(count, total_count)
+                    for ff, freq in enumerate(s.frequency.data):
+                        if callback is not None:
+                            # report progress during sweep
+                            callback(count, total_count)
 
-                    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, m=m, n=n)] = np.mean(rx[1] / rx[0])
+                        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, m=m, n=n)] = np.mean(rx[1] / rx[0])
 
-                    count += 1
+                        count += 1
 
         if callback is not None:
             # mark capture as complete
diff --git a/charon_vna/vna_dev.py b/charon_vna/vna_dev.py
index 4e8bdd2..3acff13 100644
--- a/charon_vna/vna_dev.py
+++ b/charon_vna/vna_dev.py
@@ -11,7 +11,7 @@ frequency = np.linspace(80e6, 280e6, 31)
 vna = Charon(frequency=frequency, ports=2)
 
 # %%
-s = vna.capture()
+s = vna.capture(measurements=[(2, 1), (2, 2)])
 
 # %%
 for m in s.m.data: