diff --git a/main.c b/main.c
index f324e41..86bec44 100644
--- a/main.c
+++ b/main.c
@@ -1018,15 +1018,15 @@ config_t config = {
   .high_level_output_offset =  0.0,    // Uncalibrated
   .correction_frequency =
   {
-    { 10000, 100000, 300000, 1000000, 30000000, 500000000, 750000000, 1000000000, 1500000000, 1520000000, 2000000000, 2500000000, 3000000000, 3500000000, 4000000000, 4500000000, 5000000000, 5500000000, 6000000000, 6500000000  },
-    { 10000, 100000, 300000, 1000000, 30000000, 500000000, 750000000, 1000000000, 1500000000, 1520000000, 2000000000, 2500000000, 3000000000, 3500000000, 4000000000, 4500000000, 5000000000, 5500000000, 6000000000, 6500000000 },
-    { 10000, 100000, 300000, 1000000, 30000000, 500000000, 750000000, 1000000000, 1500000000, 1520000000, 2000000000, 2500000000, 3000000000, 3500000000, 4000000000, 4500000000, 5000000000, 5500000000, 6000000000, 6500000000  },
+    { 10000, 100000, 300000, 1000000, 30000000, 500000000, 750000000, 750000010, 1000000000, 1500000000, 1520000000, 2000000000, 2500000000, 3000000000, 3500000000, 4000000000, 4500000000, 5000000000, 5500000000, 6000000000 },
+    { 10000, 100000, 300000, 1000000, 30000000, 500000000, 750000000, 750000010, 1000000000, 1500000000, 1520000000, 2000000000, 2500000000, 3000000000, 3500000000, 4000000000, 4500000000, 5000000000, 5500000000, 6000000000 },
+    { 10000, 100000, 300000, 1000000, 30000000, 500000000, 750000000, 750000010, 1000000000, 1500000000, 1520000000, 2000000000, 2500000000, 3000000000, 3500000000, 4000000000, 4500000000, 5000000000, 5500000000, 6000000000 },
   },
   .correction_value =
   {
-    { 10.5,  +4.9,   +1.6,   +0.6,    0,       0,        +4,         +2.5,       +2,         +2,         +2,         +3.5,       +6.5,       +6.5,        +9,        +9,        +9,        +11,          +11,        +11,        },
-    { 10.5,  +4.9,   +1.6,   +0.6,    0,       0,        +4,         +2.5,       +2,         +2,         +2,         +6,         +9,         +11.5,       +14.5,      +23,       +25,       +36,         +46,        +46,       },
-    { 10.5,  +4.9,   +1.6,   +0.6,    0,       0,        +4,         +2.5,       +2,         +2,         +2,         +3.5,       +6.5,       +6.5,        +9,        +9,        +9,        +11,          +11,        +11,        },
+    { 10.5,  +4.9,   +1.6,   +0.6,    0,       0,        +2,         +0,          +2,          +2,         +2,         +2,         +3.5,       +6.5,       +6.5,        +9,        +9,        +9,        +11,          +11,},
+    { 10.5,  +4.9,   +1.6,   +0.6,    0,       0,        +2,         +0,          +2,          +2,         +2,         +2,         +6,         +9,         +11.5,       +14.5,      +23,      +25,       +36,          +46,},
+    { 10.5,  +4.9,   +1.6,   +0.6,    0,       0,        +2,         +0,          +2,          +2,         +2,         +2,         +3.5,       +6.5,       +6.5,        +9,        +9,        +9,        +11,          +11,},
   },
   .setting_frequency_30mhz = 30000000,
   .cor_am = 0,
diff --git a/sa_core.c b/sa_core.c
index 60b9cd3..d494b25 100644
--- a/sa_core.c
+++ b/sa_core.c
@@ -95,7 +95,7 @@ const int8_t drive_dBm [16] = {-38, -32, -30, -27, -24, -19, -15, -12, -5, -2, 0
 #define SL_GENHIGH_LEVEL_MIN    (drive_dBm[MIN_DRIVE] - (config.high_out_adf4350 ? 0: 37 - config.switch_offset))
 #define SL_GENHIGH_LEVEL_MAX    drive_dBm[MAX_DRIVE]
 
-#define SL_GENLOW_LEVEL_MIN    -104
+#define SL_GENLOW_LEVEL_MIN    -124
 #define SL_GENLOW_LEVEL_MAX   -16
 
 
@@ -2551,6 +2551,7 @@ pureRSSI_t perform(bool break_on_operation, int i, freq_t f, int tracking)     /
       float a = ((int)((setting.level + ((float)i / sweep_points) * ls)*2.0)) / 2.0;
       a += PURE_TO_float(get_frequency_correction(f));
       if (a != old_a) {
+        int very_low_flag = false;
         old_a = a;
         a = a - level_max;                 // convert to all settings maximum power output equals a = zero
         if (a < -SWITCH_ATTENUATION) {
@@ -2560,6 +2561,7 @@ pureRSSI_t perform(bool break_on_operation, int i, freq_t f, int tracking)     /
           set_switch_receive();
 #else
           enable_rx_output(false);
+          very_low_flag = true;
 #endif
         } else {
 #ifdef TINYSA3
@@ -2567,11 +2569,16 @@ pureRSSI_t perform(bool break_on_operation, int i, freq_t f, int tracking)     /
           set_switch_transmit();
 #else
           enable_rx_output(true);
+
 #endif
         }
-
+#ifdef TINYSA4
+#define LOWEST_LEVEL (very_low_flag ? 0 : MIN_DRIVE)
+#else
+#define LOWEST_LEVEL MIN_DRIVE
+#endif
         int d = MAX_DRIVE;        // Reduce level till it fits in attenuator range
-        while (a - BELOW_MAX_DRIVE(d) < - 31 && d > MIN_DRIVE) {
+        while (a - BELOW_MAX_DRIVE(d) < - 31 && d > LOWEST_LEVEL) {
           d--;
         }
         a -= BELOW_MAX_DRIVE(d);