diff --git a/nanovna.h b/nanovna.h
index 49ab04d..5841763 100644
--- a/nanovna.h
+++ b/nanovna.h
@@ -70,6 +70,7 @@
 #define __REMOTE_DESKTOP__        // Add remote desktop option
 #define __LISTEN__
 #ifdef TINYSA4
+#define __CHANNEL_POWER__
 #define __LIMITS__
 #define  __HARMONIC__
 #else
@@ -271,6 +272,8 @@ void set_extra_lna(int t);
 extern float level_min;
 extern float level_max;
 extern float level_range;
+extern float channel_power[3];
+extern float channel_power_watt[3];
 
 extern const char * const unit_string[];
 #ifdef TINYSA4
@@ -576,6 +579,7 @@ enum unit_type {
 #define UNIT_IS_LOG(T) ( T >= U_VOLT ? false : true)
 
 float value(float);
+float index_to_value(const int i);
 
 typedef struct trace {
   uint8_t enabled;
@@ -1297,13 +1301,14 @@ void self_test(int);
 void wait_user(void);
 void calibrate(void);
 float to_dBm(float);
+float dBm_to_Watt(float);
 uint32_t calc_min_sweep_time_us(void);
 pureRSSI_t perform(bool b, int i, freq_t f, int e);
 void interpolate_maximum(int m);
 void calibrate_modulation(int modulation, int8_t *correction);
 
 enum {
-  M_OFF, M_IMD, M_OIP3, M_PHASE_NOISE, M_STOP_BAND, M_PASS_BAND, M_LINEARITY, M_AM, M_FM, M_THD
+  M_OFF, M_IMD, M_OIP3, M_PHASE_NOISE, M_STOP_BAND, M_PASS_BAND, M_LINEARITY, M_AM, M_FM, M_THD, M_CP,
 };
 
 enum {
diff --git a/plot.c b/plot.c
index 52c229f..8d0af5f 100644
--- a/plot.c
+++ b/plot.c
@@ -335,6 +335,12 @@ to_dBm(const float v)
     return v;  // raw data is in logmag*10 format
 }
 
+float
+dBm_to_Watt(const float v)
+{
+  return   logf(v*1000.0)*(10.0/logf(10.0));
+}
+
 static void
 trace_into_index_x_array(index_x_t *x, uint16_t points){
   // Not need update if index calculated for this points count
@@ -923,6 +929,13 @@ draw_cell(int m, int n)
       if (rectangular_grid_x(x + x0)) {
         for (y = 0; y < h; y++) cell_buffer[y * CELLWIDTH + x] = c;
       }
+#ifdef __CHANNEL_POWER__
+      if (setting.measurement == M_CP) {
+        if (x+x0 == WIDTH/3 || x+x0 == 2*WIDTH/3 ) {
+          for (y = 0; y < h; y++) cell_buffer[y * CELLWIDTH + x] = LCD_TRIGGER_COLOR;
+        }
+      }
+#endif
     }
     for (y = 0; y < h; y++) {
       if (rectangular_grid_y(y + y0)) {
@@ -1285,6 +1298,22 @@ static void cell_draw_marker_info(int x0, int y0)
       active++;
     }
   }
+#ifdef __CHANNEL_POWER__
+  if (setting.measurement==M_CP) {
+    char *p_label[3] = { "Left", "Mid", "Right" };
+    for (int c=0; c<3;c++) {
+      if (c == 1)
+        plot_printf(buf, sizeof buf, "%s: %4.1fdB %4.1f%%", p_label[c], channel_power[1], 100.0 * (channel_power_watt[1] - channel_power_watt[0] - channel_power_watt[2]) /channel_power_watt[1] );
+      else
+        plot_printf(buf, sizeof buf, "%s: %4.1fdB", p_label[c], channel_power[c]);
+      int xpos = 10 + (c)*(WIDTH/3) + CELLOFFSETX - x0;
+      int ypos = 1 - y0;
+      ili9341_set_foreground(LCD_FG_COLOR);
+      cell_drawstring_7x13(buf, xpos, ypos);
+    }
+    return;
+  }
+#endif
   if (setting.measurement == M_THD && active >= 1)
     active = 2;
   for (int i = 0; i < MARKER_COUNT; i++) {
diff --git a/sa_core.c b/sa_core.c
index 1955cae..34bf7dd 100644
--- a/sa_core.c
+++ b/sa_core.c
@@ -71,7 +71,7 @@ static freq_t real_old_freq[4] = { 0, 0, 0, 0};
 #endif
 
 #ifdef TINYSA4
-const float si_drive_dBm []     = {-41, -30, -21, -17, -12, -11, -10, -8.5, -7.5, -6.5, -5.5, -4.5, -3.5, -3 ,  -2,  -1.5, -1, -0.5, 0};
+const float si_drive_dBm []     = {-41, -30, -21, -17, -14, -11, -10, -8, -7, -6, -5, -4, -3, -2.5 ,  -2,  -1.5, -1, -0.5, 0};
 const float adf_drive_dBm[]     = {-15,-12,-9,-6};
 const uint8_t drive_register[]  = {0,   1,   2,   3,   4,   5,  6,   6,    8,    9,    10,   11,   12,   13,   14,  15,  16,  17,   18};
 float *drive_dBm = (float *) adf_drive_dBm;
@@ -92,7 +92,7 @@ const int8_t drive_dBm [16] = {-38, -32, -30, -27, -24, -19, -15, -12, -5, -2, 0
 #define SL_GENHIGH_LEVEL_MAX    drive_dBm[MAX_DRIVE]
 
 #define SL_GENLOW_LEVEL_MIN    -104
-#define SL_GENLOW_LEVEL_MAX   -14
+#define SL_GENLOW_LEVEL_MAX   -16
 
 
 #else
@@ -114,6 +114,8 @@ float level_min;
 float level_max;
 float level_range;
 
+float channel_power[3];
+float channel_power_watt[3];
 
 //int setting.refer = -1;  // Off by default
 const uint32_t reffer_freq[] = {30000000, 15000000, 10000000, 4000000, 3000000, 2000000, 1000000};
@@ -2276,6 +2278,7 @@ void clock_at_48MHz(void)
     RCC->CR &= RCC_CR_HSICAL;
     RCC->CR |= ( (hsical) << 8 );
     RCC->CR &= RCC_CR_HSITRIM | RCC_CR_HSION; /* CR Reset value.              */
+    RCC->CR |= RCC_CR_HSITRIM_4;
   }
 }
 
@@ -3704,6 +3707,22 @@ sweep_again:                                // stay in sweep loop when output mo
         set_AGC_LNA();
 #endif
       }
+#ifdef __CHANNEL_POWER__
+      } else if (setting.measurement == M_CP) {      // ----------------CHANNEL_POWER measurement
+        int old_unit = setting.unit;
+        setting.unit = U_WATT;
+        for (int c = 0; c < 3 ;c++) {
+          channel_power_watt[c] = 0.0;
+          int sp_div3 = sweep_points/3;
+          for (int i =0; i < sp_div3; i++) {
+            channel_power_watt[c] += index_to_value(i + c*sp_div3);
+          }
+          float rbw_cor =  (float)(get_sweep_frequency(ST_SPAN)/3) / ((float)actual_rbw_x10 * 100.0);
+          channel_power_watt[c] = channel_power_watt[c] * rbw_cor /(float)sp_div3;
+          channel_power[c] = to_dBm(channel_power_watt[c]);
+        }
+        setting.unit = old_unit;
+#endif
     }
 
 #endif
diff --git a/ui_sa.c b/ui_sa.c
index ff84b80..edaeaa4 100644
--- a/ui_sa.c
+++ b/ui_sa.c
@@ -908,6 +908,8 @@ static UI_FUNCTION_ADV_CALLBACK(menu_measure_acb)
   switch(data) {
     case M_OFF:                                     // Off
 //      reset_settings(setting.mode);
+      markers[0].enabled = M_ENABLED;
+      markers[0].mtype = M_REFERENCE | M_TRACKING;
    no_measurement:
       set_measurement(M_OFF);
       break;
@@ -1069,6 +1071,18 @@ static UI_FUNCTION_ADV_CALLBACK(menu_measure_acb)
     case M_THD:
       set_measurement(M_THD);
       break;
+#ifdef __CHANNEL_POWER__
+    case M_CP:                             // channel power
+      reset_settings(setting.mode);
+      markers[0].enabled = M_DISABLED;
+      kp_help_text = "Channel frequency";
+      ui_mode_keypad(KM_CENTER);
+      kp_help_text = "Channel width";
+      ui_mode_keypad(KM_SPAN);
+      set_sweep_frequency(ST_SPAN, uistat.value*3);
+      set_measurement(M_CP);
+      break;
+#endif
   }
 #endif
 //  selection = -1;
@@ -2031,7 +2045,10 @@ static const menuitem_t menu_measure2[] = {
   { MT_ADV_CALLBACK,            M_AM,           "AM",           menu_measure_acb},
   { MT_ADV_CALLBACK,            M_FM,           "FM",           menu_measure_acb},
   { MT_ADV_CALLBACK,            M_THD,          "THD",           menu_measure_acb},
-#ifdef __LINEARITY__
+#ifdef __CHANNEL_POWER__
+  { MT_ADV_CALLBACK,            M_CP,           "CHANNEL\nPOWER",menu_measure_acb},
+#endif
+  #ifdef __LINEARITY__
   { MT_ADV_CALLBACK | MT_LOW,   M_LINEARITY,  "LINEAR",         menu_measure_acb},
 #endif
   { MT_CANCEL, 0,               S_LARROW" BACK", NULL },