diff --git a/main.c b/main.c
index e9233e4..cb784dd 100644
--- a/main.c
+++ b/main.c
@@ -2057,6 +2057,7 @@ static const VNAShellCommand commands[] =
     { "agc", cmd_agc,    CMD_RUN_IN_LOAD },
 #endif
     { "actual_freq", cmd_actual_freq, CMD_WAIT_MUTEX | CMD_RUN_IN_LOAD },
+    { "freq_corr", cmd_freq_correction, CMD_WAIT_MUTEX | CMD_RUN_IN_LOAD },
     { "attenuate", cmd_attenuate,    CMD_WAIT_MUTEX | CMD_RUN_IN_LOAD },
     { "level", cmd_level,    CMD_WAIT_MUTEX | CMD_RUN_IN_LOAD },
     { "sweeptime", cmd_sweeptime,    CMD_WAIT_MUTEX | CMD_RUN_IN_LOAD },
diff --git a/nanovna.h b/nanovna.h
index 41c9569..6c1fb4e 100644
--- a/nanovna.h
+++ b/nanovna.h
@@ -18,7 +18,7 @@
  */
 #include "ch.h"
 
-#ifdef TINYSA_F303
+//#ifdef TINYSA_F303
 #ifdef TINYSA_F072
 #error "Remove comment for #ifdef TINYSA_F303"
 #endif
@@ -26,7 +26,7 @@
 #define TINYSA4
 #endif
 #define TINYSA4_PROTO
-#endif
+//#endif
 
 #ifdef TINYSA_F072
 #ifdef TINYSA_F303
@@ -457,7 +457,8 @@ void clear_frequency_cache(void);
 void toggle_high_out_adf4350(void);
 extern int high_out_adf4350;
 #endif
-int set_actual_freq(int);
+int set_actual_freq(freq_t);
+int set_freq_corr(int);
 void set_IF2(int f);
 void set_R(int f);
 extern void set_modulo(uint32_t f);
diff --git a/sa_cmd.c b/sa_cmd.c
index 7c036b1..d733939 100644
--- a/sa_cmd.c
+++ b/sa_cmd.c
@@ -605,12 +605,24 @@ VNA_SHELL_FUNCTION(cmd_if1)
 VNA_SHELL_FUNCTION(cmd_actual_freq)
 {
   if (argc != 1 || argv[0][0] == '?') {
-    shell_printf("%DHz\r\n", config.setting_frequency_30mhz);
+    shell_printf("%D\r\n", config.setting_frequency_30mhz);
     return;
   } else {
     set_actual_freq(my_atoui(argv[0]));
   }
 }
+
+
+VNA_SHELL_FUNCTION(cmd_freq_correction)
+{
+  if (argc != 1 || argv[0][0] == '?') {
+    shell_printf("%d ppb\r\n", (int)(((int64_t)config.setting_frequency_30mhz - (int64_t)3000000000ULL)/3));
+    return;
+  } else {
+    set_freq_corr(my_atoi(argv[0]));
+  }
+}
+
 #endif
 
 
diff --git a/sa_core.c b/sa_core.c
index 5655d5d..50f90c7 100644
--- a/sa_core.c
+++ b/sa_core.c
@@ -819,7 +819,7 @@ void set_gridlines(int d)
 
 #ifdef TINYSA4
 
-int set_actual_freq(int f)
+int set_freq_corr(int f)
 {
   if (f < - 100000 || f > +100000)
     return -1;
@@ -830,6 +830,18 @@ int set_actual_freq(int f)
   update_grid();
   return 0;
 }
+
+int set_actual_freq(freq_t f)
+{
+  if (f < 3000000000 - 30000 || f > 3000000000 + 30000)
+    return -1;
+  config.setting_frequency_30mhz =f;
+  ADF4351_recalculate_PFDRFout();
+  config_save();
+  dirty = true;
+  update_grid();
+  return 0;
+}
 #else
 void set_10mhz(freq_t f)
 {
@@ -5326,7 +5338,7 @@ static volatile int dummy;
         }
       }
     }
-
+  }
 
 
 #define __MIRROR_MASKING__
@@ -5369,7 +5381,7 @@ static volatile int dummy;
 #ifdef TINYSA4_4
       && !setting.extra_lna
 #endif
-      ) {  // calculate and apply auto attenuate
+  ) {  // calculate and apply auto attenuate
     setting.atten_step = false;     // No step attenuate in low mode auto attenuate
     int changed = false;
     int delta = 0;
@@ -5414,7 +5426,7 @@ static volatile int dummy;
 #endif
 #endif
       calculate_static_correction();            // Update correction
-//      dirty = true;                               // Needed to recalculate the correction factor
+      //      dirty = true;                               // Needed to recalculate the correction factor
     }
   }
 
@@ -5629,7 +5641,7 @@ static volatile int dummy;
   }
 
 #endif
-  }
+
   //  } while (MODE_OUTPUT(setting.mode) && setting.modulation != MO_NONE);      // Never exit sweep loop while in output mode with modulation
 #if 0       // Read ADC
   extern   int fix_fft(short fr[], short fi[], short m, short inverse);
diff --git a/ui_sa.c b/ui_sa.c
index 1c29209..13d9a3b 100644
--- a/ui_sa.c
+++ b/ui_sa.c
@@ -575,7 +575,7 @@ char range_text[20];
 #ifdef TINYSA4
 int input_is_calibrated(void)
 {
-  if (!config.input_is_calibrated)
+  if (config.input_is_calibrated)
     return true;
   drawMessageBox("Error", "First calibrate 100kHz to 5.34GHz input", 2000);
   redraw_request|= REDRAW_AREA;
@@ -584,7 +584,7 @@ int input_is_calibrated(void)
 
 int output_is_calibrated(void)
 {
-  if (!config.output_is_calibrated)
+  if (config.output_is_calibrated)
     return true;
   drawMessageBox("Error", "First calibrate 30MHz output", 2000);
   redraw_request|= REDRAW_AREA;