diff --git a/main.c b/main.c
index 88b429a..96ffcb6 100644
--- a/main.c
+++ b/main.c
@@ -374,6 +374,7 @@ ensure_edit_config(void)
 
   //memcpy(&current_config, active, sizeof(config_t));
   active = &current_config;
+  // move to uncal state
   cal_status = 0;
 }
 
@@ -459,15 +460,16 @@ update_frequencies(void)
     start = freq_start;
     span = (freq_stop - freq_start)/100;
   } else {
-    span = -freq_stop / 100;
+    span = -freq_stop;
     start = freq_start - span/2;
+    span /= 100;
   }
 
   for (i = 0; i < sweep_points; i++)
     frequencies[i] = start + span * i / (sweep_points - 1) * 100;
 
   // set grid layout
-  set_sweep(freq_start, freq_stop);
+  update_grid();
 }
 
 
diff --git a/nanovna.h b/nanovna.h
index 5c4aa56..f557a8e 100644
--- a/nanovna.h
+++ b/nanovna.h
@@ -150,7 +150,7 @@ typedef struct {
 //extern int active_marker;
 
 void plot_init(void);
-void set_sweep(int32_t start, int stop);
+void update_grid(void);
 void redraw(void);
 void force_draw_cells(void);
 void redraw_marker(int marker, int update_info);
diff --git a/plot.c b/plot.c
index e027f7f..88af7e2 100644
--- a/plot.c
+++ b/plot.c
@@ -63,25 +63,21 @@ int active_marker = 0;
 #endif
 
 
-int32_t fstart = 0;
-int32_t fstop = 300000000;
-int32_t fspan = 300000000;
 int32_t fgrid = 50000000;
 int16_t grid_offset;
 int16_t grid_width;
 
-void set_sweep(int32_t start, int stop)
+void update_grid(void)
 {
   int32_t gdigit = 100000000;
+  int32_t fstart, fspan;
   int32_t grid;
-  if (stop > 0) {
-    fstart = start;
-    fstop = stop;
-    fspan = stop - start;
+  if (freq_stop > 0) {
+    fstart = freq_start;
+    fspan = freq_stop - freq_start;
   } else {
-    fspan = -stop;
-    fstart = start;
-    fstop = stop;
+    fspan = -freq_stop;
+    fstart = freq_start - fspan/2;
   }
   
   while (gdigit > 100) {
@@ -1240,20 +1236,20 @@ void
 draw_frequencies(void)
 {
   char buf[24];
-  if (fstop > 0) {
+  if (freq_stop > 0) {
     chsnprintf(buf, 24, "START %d.%03d %03d MHz  ",
-               (int)(fstart / 1000000),
-               (int)((fstart / 1000) % 1000),
-               (int)(fstart % 1000));
+               (int)(freq_start / 1000000),
+               (int)((freq_start / 1000) % 1000),
+               (int)(freq_start % 1000));
     ili9341_drawstring_5x7(buf, OFFSETX, 233, 0xffff, 0x0000);
     chsnprintf(buf, 24, "STOP %d.%03d %03d MHz",
-               (int)(fstop / 1000000),
-               (int)((fstop / 1000) % 1000),
-               (int)(fstop % 1000));
+               (int)(freq_stop / 1000000),
+               (int)((freq_stop / 1000) % 1000),
+               (int)(freq_stop % 1000));
     ili9341_drawstring_5x7(buf, 205, 233, 0xffff, 0x0000);
-  } else if (fstop < 0) {
-    int fcenter = fstart;
-    int fspan = -fstop;
+  } else if (freq_stop < 0) {
+    int fcenter = freq_start;
+    int fspan = -freq_stop;
     chsnprintf(buf, 24, "CENTER %d.%03d %03d MHz  ",
                (int)(fcenter / 1000000),
                (int)((fcenter / 1000) % 1000),
@@ -1265,7 +1261,7 @@ draw_frequencies(void)
                (int)(fspan % 1000));
     ili9341_drawstring_5x7(buf, 205, 233, 0xffff, 0x0000);
   } else {
-    int fcenter = fstart;
+    int fcenter = freq_start;
     chsnprintf(buf, 24, "CW %d.%03d %03d MHz    ",
                (int)(fcenter / 1000000),
                (int)((fcenter / 1000) % 1000),
diff --git a/ui.c b/ui.c
index 741f8cd..65ff357 100644
--- a/ui.c
+++ b/ui.c
@@ -227,7 +227,7 @@ menu_recall_cb(int item)
     return;
   if (caldata_recall(item) == 0) {
     ui_mode_normal();
-    set_sweep(freq_start, freq_stop);
+    update_grid();
     draw_cal_status();
   }
 }