diff --git a/owrx/form/converter.py b/owrx/form/converter.py
index 7739591..7997cd9 100644
--- a/owrx/form/converter.py
+++ b/owrx/form/converter.py
@@ -1,4 +1,5 @@
 from abc import ABC, abstractmethod
+import json
 
 
 class Converter(ABC):
@@ -59,3 +60,9 @@ class EnumConverter(Converter):
         return self.enumCls[value].value
 
 
+class JsonConverter(Converter):
+    def convert_to_form(self, value):
+        return json.dumps(value)
+
+    def convert_from_form(self, value):
+        return json.loads(value)
diff --git a/owrx/form/wsjt.py b/owrx/form/wsjt.py
index ec79654..52bd50f 100644
--- a/owrx/form/wsjt.py
+++ b/owrx/form/wsjt.py
@@ -1,4 +1,5 @@
 from owrx.form import Input
+from owrx.form.converter import JsonConverter
 from owrx.wsjt import Q65Mode, Q65Interval
 from owrx.modes import Modes, WsjtMode
 import json
@@ -56,6 +57,9 @@ class Q65ModeMatrix(Input):
 
 
 class WsjtDecodingDepthsInput(Input):
+    def defaultConverter(self):
+        return JsonConverter()
+
     def render_input(self, value):
         def render_mode(m):
             return """
@@ -74,7 +78,7 @@ class WsjtDecodingDepthsInput(Input):
         """.format(
             id=self.id,
             classes=self.input_classes(),
-            value=html.escape(json.dumps(value)),
+            value=html.escape(value),
             options="".join(render_mode(m) for m in Modes.getAvailableModes() if isinstance(m, WsjtMode)),
         )