diff --git a/swagger/sdrangel/api/swagger/include/FreqTracker.yaml b/swagger/sdrangel/api/swagger/include/FreqTracker.yaml
index 0462108eb..68a029cd5 100644
--- a/swagger/sdrangel/api/swagger/include/FreqTracker.yaml
+++ b/swagger/sdrangel/api/swagger/include/FreqTracker.yaml
@@ -63,6 +63,9 @@ FreqTrackerReport:
       description: power received in channel (dB)
       type: number
       format: float
+    trackingDeltaFrequency:
+      description: difference between channel and PLL or FLL center frequency (Hz)
+      type: integer
     squelch:
       description: squelch status (1 if open else 0)
       type: integer