diff --git a/firmware/application/apps/ui_settings.cpp b/firmware/application/apps/ui_settings.cpp
index 58ce5a12..66a89d63 100644
--- a/firmware/application/apps/ui_settings.cpp
+++ b/firmware/application/apps/ui_settings.cpp
@@ -194,8 +194,8 @@ SetRadioView::SetRadioView(
 
     field_clkout_freq.set_value(pmem::clkout_freq());
     field_clkout_freq.on_change = [this](SymField&) {
-        if (field_clkout_freq.to_integer() < 10)
-            field_clkout_freq.set_value(10);
+        if (field_clkout_freq.to_integer() < 4)  // Min. CLK out of Si5351A/B/C-B is 2.5khz , but in our application -intermediate freq 800Mhz-,Min working CLK=4khz.
+            field_clkout_freq.set_value(4);
         if (field_clkout_freq.to_integer() > 60000)
             field_clkout_freq.set_value(60000);
     };
diff --git a/firmware/common/portapack_persistent_memory.cpp b/firmware/common/portapack_persistent_memory.cpp
index 8f83282f..6afafea7 100644
--- a/firmware/common/portapack_persistent_memory.cpp
+++ b/firmware/common/portapack_persistent_memory.cpp
@@ -77,7 +77,7 @@ constexpr modem_repeat_range_t modem_repeat_range{1, 99};
 constexpr int32_t modem_repeat_reset_value{5};
 
 using clkout_freq_range_t = range_t<uint32_t>;
-constexpr clkout_freq_range_t clkout_freq_range{10, 60000};
+constexpr clkout_freq_range_t clkout_freq_range{4, 60000};  // Min. CLK out of Si5351A/B/C-B is 2.5khz , but in our application -intermediate freq 800Mhz-,Min working CLK=4khz.
 constexpr uint16_t clkout_freq_reset_value{10000};
 
 enum data_structure_version_enum : uint32_t {