Consider Channel Spacing (50, 25, 8.33kHz) for COM frequencies.

Deals with a special topic: While frequencies at VATSIM/flightsim are usually set in 25kHz spacing, some ATC stations (radar) require 8.33kHz tuning.
The now made extension handles this and allows to listen to a voice room even if the corresponding frequency is not exactly tuned in.

Example: EKDK_CTR 135,270 but needs to be tuned in as 135,275

src/blackmisc/aviobase.h

@@ -79,8 +79,7 @@ namespace BlackMisc
             }
 
             /*!
-             * \brief Stream to DBus <<
-             * \param argument
+             * \copydoc CValueObject::marshallToDbus()
              */
             virtual void marshallToDbus(QDBusArgument &argument) const
             {
@@ -88,8 +87,7 @@ namespace BlackMisc
             }
 
             /*!
-             * \brief Stream from DBus >>
-             * \param argument
+             * \copydoc CValueObject::unmarshallFromDbus()
              */
             virtual void unmarshallFromDbus(const QDBusArgument &argument)
             {