diff --git a/Radio.cpp b/Radio.cpp
index ed4bf388d..5ee290406 100644
--- a/Radio.cpp
+++ b/Radio.cpp
@@ -54,7 +54,7 @@ namespace Radio
     value *= std::pow (10., scale);
     if (ok)
       {
-        if (value < 0. || value > std::numeric_limits<Frequency>::max ())
+        if (value < 0. || value > static_cast<double>(std::numeric_limits<Frequency>::max ()))
           {
             value = 0.;
             *ok = false;
@@ -91,8 +91,8 @@ namespace Radio
     value *= std::pow (10., scale);
     if (ok)
       {
-        if (value < -std::numeric_limits<Frequency>::max ()
-            || value > std::numeric_limits<Frequency>::max ())
+        if (value < static_cast<double>(std::numeric_limits<Frequency>::min ())
+            || value > static_cast<double>(std::numeric_limits<Frequency>::max ()))
           {
             value = 0.;
             *ok = false;
diff --git a/widgets/FrequencyDeltaLineEdit.cpp b/widgets/FrequencyDeltaLineEdit.cpp
index b7ed144b6..59ae9bc9c 100644
--- a/widgets/FrequencyDeltaLineEdit.cpp
+++ b/widgets/FrequencyDeltaLineEdit.cpp
@@ -39,8 +39,8 @@ namespace
 FrequencyDeltaLineEdit::FrequencyDeltaLineEdit (QWidget * parent)
   : QLineEdit (parent)
 {
-  setValidator (new MHzValidator {-std::numeric_limits<FrequencyDelta>::max () / 10.e6,
-        std::numeric_limits<FrequencyDelta>::max () / 10.e6, this});
+  setValidator (new MHzValidator {static_cast<double>(std::numeric_limits<FrequencyDelta>::min ()) / 10.e6,
+        static_cast<double>(std::numeric_limits<FrequencyDelta>::max ()) / 10.e6, this});
 }
 
 auto FrequencyDeltaLineEdit::frequency_delta () const -> FrequencyDelta
diff --git a/widgets/FrequencyLineEdit.cpp b/widgets/FrequencyLineEdit.cpp
index 1ca2ba20b..8e74c7db4 100644
--- a/widgets/FrequencyLineEdit.cpp
+++ b/widgets/FrequencyLineEdit.cpp
@@ -39,7 +39,7 @@ namespace
 FrequencyLineEdit::FrequencyLineEdit (QWidget * parent)
   : QLineEdit (parent)
 {
-  setValidator (new MHzValidator {0., std::numeric_limits<Radio::Frequency>::max () / 10.e6, this});
+  setValidator (new MHzValidator {0., static_cast<double>(std::numeric_limits<Radio::Frequency>::max ()) / 10.e6, this});
 }
 
 auto FrequencyLineEdit::frequency () const -> Frequency