diff --git a/nanovna.h b/nanovna.h
index 281a0e1..0cfa323 100644
--- a/nanovna.h
+++ b/nanovna.h
@@ -593,7 +593,7 @@ typedef struct setting
   int tracking;
   int modulation;
   int step_delay;
-  int frequency_step;
+  uint32_t frequency_step;
   int test;
   int harmonic;
   int decay;
diff --git a/sa_cmd.c b/sa_cmd.c
index c50b4de..a9bbe5c 100644
--- a/sa_cmd.c
+++ b/sa_cmd.c
@@ -549,9 +549,9 @@ VNA_SHELL_FUNCTION(cmd_scanraw)
   if (argc == 3) {
     points = my_atoi(argv[2]);
   }
-  int old_step = setting.frequency_step;
+  uint32_t old_step = setting.frequency_step;
   float f_step = (stop-start)/ points;
-  setting.frequency_step = (int32_t)f_step;
+  setting.frequency_step = (uint32_t)f_step;
 
   streamPut(shell_stream, '{');
   static  uint32_t old_start=0, old_stop=0, old_points=0;
@@ -565,7 +565,7 @@ VNA_SHELL_FUNCTION(cmd_scanraw)
   for (uint32_t i = 0; i<points; i++) {
     if (operation_requested)
       break;
-    float val = perform(false, i, start +(int32_t)(f_step * i), false);
+    float val = perform(false, i, start +(uint32_t)(f_step * i), false);
     streamPut(shell_stream, 'x');
     int v = val*2 + 256;
     streamPut(shell_stream, (uint8_t)(v & 0xFF));
diff --git a/sa_core.c b/sa_core.c
index aabc80a..5be1455 100644
--- a/sa_core.c
+++ b/sa_core.c
@@ -797,7 +797,7 @@ void calculate_step_delay(void)
       SI4432_offset_delay = setting.offset_delay;
   } else {
     SI4432_offset_delay = 0;
-    if (setting.frequency_step == 0.0) {          // zero span mode, not dependent on selected RBW
+    if (setting.frequency_step == 0) {            // zero span mode, not dependent on selected RBW
       SI4432_step_delay = 0;
     } else {
       if (actual_rbw_x10 >= 1910)      { SI4432_step_delay =  280; SI4432_offset_delay = 100; }