diff --git a/nanovna.h b/nanovna.h
index e49e55c..3c952b5 100644
--- a/nanovna.h
+++ b/nanovna.h
@@ -639,8 +639,8 @@ enum { S_OFF=0, S_ON=1, S_AUTO_OFF=2, S_AUTO_ON=3 };
 #define ONE_SECOND_TIME     1000000U // One second uS
 #define ONE_MS_TIME         1000U    // One ms uS
 
-#define REPEAT_TIME         134         // Time per extra repeat in uS
-#define MEASURE_TIME        175         // Time per vbwstep without stepdelay in uS
+#define REPEAT_TIME         110         // Time per extra repeat in uS
+#define MEASURE_TIME        127         // Time per vbwstep without step delay in uS
 
 extern uint32_t frequencies[POINTS_COUNT];
 extern const float unit_scale_value[];
diff --git a/sa_core.c b/sa_core.c
index ad6f404..98c4650 100644
--- a/sa_core.c
+++ b/sa_core.c
@@ -31,6 +31,7 @@ float actual_rbw = 0;
 int vbwSteps = 1;
 uint32_t minFreq = 0;
 uint32_t maxFreq = 520000000;
+uint32_t measured_sweep_time = 0;
 
 //int setting.refer = -1;  // Off by default
 int const reffer_freq[] = {30000000, 15000000, 10000000, 4000000, 3000000, 2000000, 1000000};
@@ -1594,12 +1595,14 @@ again:                          // Waiting for a trigger jumps back to here
   if (MODE_OUTPUT(setting.mode) && t < 500)     // Minimum wait time to prevent LO from lockup during output frequency sweep
     t = 500;
 
-  set_freq_time = 0;                        // for predicting the weep time
 
 sweep_again:                                // stay in sweep loop when output mode and modulation on.
 
+  set_freq_time = 0;                        // for predicting the weep time
+
   // ------------------------- start sweep loop -----------------------------------
-  //   START_PROFILE;
+  START_PROFILE;        // needed to measure actual sweep time except for fast scan in zero span mode
+
   for (int i = 0; i < sweep_points; i++) {
 
     if (start_index == -1 && start_time == 0 && set_freq_time != 0) {           // Sweep time prediction: first real set SI4432 freq
@@ -1732,7 +1735,8 @@ sweep_again:                                // stay in sweep loop when output mo
     goto sweep_again;                                             // Keep repeating sweep loop till user aborts by input
 
 
-  //  STOP_PROFILE;
+  measured_sweep_time = DELTA_TIME*100;                         // in us
+  //STOP_PROFILE;
   // --------------- check if maximum is above trigger level -----------------
 
   if (setting.trigger != T_AUTO && setting.frequency_step > 0) {    // Trigger active
diff --git a/si4432.c b/si4432.c
index 2543b6a..247a0b4 100644
--- a/si4432.c
+++ b/si4432.c
@@ -448,7 +448,7 @@ float SI4432_RSSI(uint32_t i, int s)
     }
     SI4432_frequency_changed = false;
   } else if (SI4432_offset_changed) {
-    stepdelay = 280 + stepdelay/8;
+    stepdelay = 280 + (stepdelay - 280)/8;
     SI4432_offset_changed = false;
   }
   if (stepdelay)