diff --git a/lib/anytone_extension.hh b/lib/anytone_extension.hh
index 01df1f8f..c17f6e4a 100644
--- a/lib/anytone_extension.hh
+++ b/lib/anytone_extension.hh
@@ -119,6 +119,7 @@ public:
   /** Holds the APRS PTT mode. That his, if and when the APRS information is send via the
    * associated APRS system. */
   APRSPTT aprsPTT() const;
+  /** Sets the APRS PTT mode. */
   void setAPRSPTT(APRSPTT mode);
 
 protected:
diff --git a/lib/c7000device.cc b/lib/c7000device.cc
index 37bdf456..e23d9bec 100644
--- a/lib/c7000device.cc
+++ b/lib/c7000device.cc
@@ -96,7 +96,7 @@ C7000Device::Packet::payloadSize() const {
 
 QByteArray
 C7000Device::Packet::payload() const {
-  return _encoded.mid(8,payloadSize());
+  return _encoded.mid(8, payloadSize());
 }
 
 const QByteArray &
diff --git a/lib/c7000device.hh b/lib/c7000device.hh
index 636c4baf..7bfd0deb 100644
--- a/lib/c7000device.hh
+++ b/lib/c7000device.hh
@@ -32,11 +32,17 @@ public:
     /** Returns @c true, if the packet is valid. */
     bool isValid() const;
 
+    /** Returns the flags field. */
     uint8_t flags() const;
+    /** Returns the command field. */
     uint8_t command() const;
+    /** Returns the sub-command field. */
     uint8_t subcommand() const;
+    /** Returns the payload size. */
     uint16_t payloadSize() const;
+    /** Returns the payload field. */
     QByteArray payload() const;
+    /** Returns the encoded packet. */
     const QByteArray &encoded() const;
 
   protected:
diff --git a/lib/configmergevisitor.hh b/lib/configmergevisitor.hh
index 41b5a6db..ce89fdac 100644
--- a/lib/configmergevisitor.hh
+++ b/lib/configmergevisitor.hh
@@ -44,6 +44,7 @@ public:
   /** Constructor of the merge visitor.
    * @param destination Specifies the destination configuration, the additional configurations are
    *        merged into.
+   * @param translation Specifies the translation table to fill of objects being replaced.
    * @param itemStrategy Specifies the item merge strategy.
    * @param setStrategy Specifies the set merge strategy. */
   ConfigMergeVisitor(Config *destination, QHash<ConfigObject *, ConfigObject *> &translation,
diff --git a/lib/d878uv_codeplug.hh b/lib/d878uv_codeplug.hh
index 9c3cf8e3..0abe4308 100644
--- a/lib/d878uv_codeplug.hh
+++ b/lib/d878uv_codeplug.hh
@@ -1176,8 +1176,7 @@ public:
   };
 
 
-  /** Implements some storage to hold the names for the FM APRS frequencies.
-   * @verbinclude d878uv_fm_aprs_frequency_names.txt */
+  /** Implements some storage to hold the names for the FM APRS frequencies. */
   class FMAPRSFrequencyNamesElement: public Element
   {
   protected:
diff --git a/lib/dmr6x2uv_codeplug.hh b/lib/dmr6x2uv_codeplug.hh
index d113bf51..37a3bef0 100644
--- a/lib/dmr6x2uv_codeplug.hh
+++ b/lib/dmr6x2uv_codeplug.hh
@@ -916,8 +916,9 @@ public:
     bool fromChannelObj(const Channel *c, Context &ctx);
 
 public:
+    /** Some limits of this element. */
     struct Limit {
-      // Maximum number of scan list indices.
+      /// Maximum number of scan list indices.
       static constexpr unsigned int scanListIndices() { return 8; }
     };
 
diff --git a/lib/encryptionextension.hh b/lib/encryptionextension.hh
index a758445b..ebae09e8 100644
--- a/lib/encryptionextension.hh
+++ b/lib/encryptionextension.hh
@@ -139,6 +139,7 @@ public:
 
   int add(ConfigObject *obj, int row=-1, bool unique=true);
 
+  /** Returns the key the given index. */
   EncryptionKey *key(int index) const;
 
   ConfigItem *allocateChild(const YAML::Node &node, ConfigItem::Context &ctx, const ErrorStack &err=ErrorStack());
diff --git a/lib/gd73_codeplug.hh b/lib/gd73_codeplug.hh
index b813260d..1c731690 100644
--- a/lib/gd73_codeplug.hh
+++ b/lib/gd73_codeplug.hh
@@ -183,9 +183,12 @@ public:
     /** Possible programmable key function. */
     struct KeyFunction {
     public:
+      /** Encodes the given function. */
       static uint8_t encode(RadioddityButtonSettingsExtension::Function func);
+      /** Decodes the given function code. */
       static RadioddityButtonSettingsExtension::Function decode(uint8_t code);
     protected:
+      /** Possible function codes. */
       enum Code {
         None=0, RadioEnable=1, RadioCheck=2, RadioDisable=3, PowerLevel=4,
         Monitor=5, EmergencyOn=6, EmergencyOff=7, ZoneSwitch=8, ToggleScan=9, ToggleVOX=10,
@@ -1275,7 +1278,9 @@ public:
     /** Sets the key size in bits. */
     void setKeySize(unsigned int size);
 
+    /** Decodes the encryption key. */
     BasicEncryptionKey *createEncryptionKey(const ErrorStack &err=ErrorStack()) const;
+    /** Encodes the encryption key. */
     bool encodeEncryptionKey(BasicEncryptionKey *key, const ErrorStack &err=ErrorStack());
 
   protected:
diff --git a/lib/opengd77_callsigndb.hh b/lib/opengd77_callsigndb.hh
index 5c62abae..f41853ed 100644
--- a/lib/opengd77_callsigndb.hh
+++ b/lib/opengd77_callsigndb.hh
@@ -28,14 +28,12 @@ public:
   bool encode(UserDatabase *calldb, const Selection &selection=Selection(),
               const ErrorStack &err=ErrorStack());
 
-public:
-  struct Limit: public OpenGD77BaseCallsignDB::Limit {
-
-  };
-
 protected:
+  /** Some internal offsets within the callsign db. */
   struct Offset {
+    /// @cond DO_NOT_DOCUMENT
     static constexpr unsigned int callsignDB() { return 0x30000; }
+    /// @endcond
   };
 };
 
diff --git a/lib/opengd77_interface.hh b/lib/opengd77_interface.hh
index 8a61de4c..84a49861 100644
--- a/lib/opengd77_interface.hh
+++ b/lib/opengd77_interface.hh
@@ -161,6 +161,7 @@ public:
   /** The Flash memory bank. */
   static const uint32_t FLASH  = 1;
 
+  /** Specifies the detected model variant. */
   enum class Variant {
     GD77, UV380
   };
diff --git a/lib/opengd77base_codeplug.hh b/lib/opengd77base_codeplug.hh
index 19758dbb..866e10a6 100644
--- a/lib/opengd77base_codeplug.hh
+++ b/lib/opengd77base_codeplug.hh
@@ -10,7 +10,8 @@
 
 #include <QGeoCoordinate>
 
-
+/** Base codeplug for all OpenGD77 based firmware variants.
+ * @ingroup ogd77 */
 class OpenGD77BaseCodeplug : public Codeplug
 {
   Q_OBJECT
@@ -31,8 +32,7 @@ public:
   static SelectiveCall decodeSelectiveCall(uint16_t code);
 
 public:
-  /** Implements the base for all OpenGD77 channel encodings.
-   */
+  /** Implements the base for all OpenGD77 channel encodings. */
   class ChannelElement: public Codeplug::Element
   {
   public:
@@ -265,6 +265,7 @@ public:
       static constexpr Bit skipZoneScan() { return {0x0033, 5}; }
       static constexpr Bit vox() { return {0x0033, 6}; }
       static constexpr unsigned int squelch() { return 0x0037; }
+      /// @endcond
     };
   };
 
@@ -459,10 +460,12 @@ public:
   class APRSSettingsElement: public Element
   {
   public:
+    /** Possible APRS baud rates. */
     enum class BaudRate {
       Baud300 = 1, Baud1200 = 0
     };
 
+    /** Possible position precisions. */
     enum class PositionPrecision {
       Max = 0,
       Mask1_8sec = 1,
@@ -563,14 +566,17 @@ public:
   public:
     /** Some limits. */
     struct Limit: public Element::Limit {
+      /** The maximum name length in chars. */
       static constexpr unsigned int nameLength() { return 8; }
+      /** The maximum comment length in chars. */
       static constexpr unsigned int commentLength() { return 23; }
     };
 
   protected:
-    /// @cond DO_NOT_DOCUMENT
+    /** Some internal offsets within the element. */
     struct Offset: public Element::Offset
     {
+      /// @cond DO_NOT_DOCUMENT
       static constexpr unsigned int name() { return 0x0000; }
       static constexpr unsigned int sourceSSID() { return 0x0008; }
       static constexpr unsigned int latitude() { return 0x0009; }
@@ -585,8 +591,8 @@ public:
       static constexpr Bit positionPrecision() { return { 0x003d, 4}; }
       static constexpr Bit useFixedPosition() { return { 0x003d, 1}; }
       static constexpr Bit baudRate() { return { 0x003d, 0}; }
+      /// @endcond
     };
-    /// @endcond
   };
 
 
@@ -908,6 +914,7 @@ public:
   };
 
 
+  /** Encodes an orbital element of OpenGD77 devices. */
   class OrbitalElement: public Element
   {
   protected:
@@ -1067,8 +1074,11 @@ public:
   class ContactElement: public Element
   {
   public:
+    /** Possible modes of time slot override. */
     enum class TimeSlotOverride {
-      None, TS1, TS2
+      None, ///< Do not override time slot.
+      TS1,  ///< Override with time slot 1.
+      TS2   ///< Override with time slot 2.
     };
 
   protected:
@@ -1293,9 +1303,11 @@ public:
   };
 
 
-public:
+protected:
+  /** Default hidden constructor. */
   explicit OpenGD77BaseCodeplug(QObject *parent = nullptr);
 
+public:
   /** Clears and resets the complete codeplug to some default values. */
   virtual void clear();
 
diff --git a/lib/openuv380_callsigndb.hh b/lib/openuv380_callsigndb.hh
index f81b1560..85cd39d1 100644
--- a/lib/openuv380_callsigndb.hh
+++ b/lib/openuv380_callsigndb.hh
@@ -28,14 +28,12 @@ public:
   bool encode(UserDatabase *calldb, const Selection &selection=Selection(),
               const ErrorStack &err=ErrorStack());
 
-public:
-  struct Limit: public OpenGD77BaseCallsignDB::Limit {
-
-  };
-
 protected:
+  /** Some internal offsets within the callsign db. */
   struct Offset {
+    /// @cond DO_NOT_DOCUMENT
     static constexpr unsigned int callsignDB() { return 0x00050000; }
+    /// @endcond
   };
 };
 
diff --git a/lib/orbitalelementsdatabase.hh b/lib/orbitalelementsdatabase.hh
index dd3c9769..979111ad 100644
--- a/lib/orbitalelementsdatabase.hh
+++ b/lib/orbitalelementsdatabase.hh
@@ -1,3 +1,6 @@
+/** @defgroup sat Satellite tracking settings.
+ * @ingroup conf */
+
 #ifndef ORBITALELEMENTSDATABASE_HH
 #define ORBITALELEMENTSDATABASE_HH
 
@@ -5,16 +8,27 @@
 #include <QNetworkAccessManager>
 
 
+/** Defines a single orbital element, enabling the tracking of a single satellite. This dataset
+ * does not contain any transponder information.
+ * @ingroup sat */
 class OrbitalElement
 {
 public:
+  /** Represents a Julien day epoch since a specified year. */
   struct Epoch {
+    /** The year of the epoch. */
     unsigned int year;
+    /** The month. */
     unsigned int month;
+    /** The day. */
     unsigned int day;
+    /** The hour. */
     unsigned int hour;
+    /** The minute. */
     unsigned int minute;
+    /** The second. */
     unsigned int second;
+    /** The microsecond. */
     unsigned int microsecond;
 
     /** Default constructor. */
@@ -27,8 +41,11 @@ public:
     /** Copy assignment. */
     Epoch &operator =(const Epoch &other) = default;
 
+    /** Parses a date-time string into the epoch. */
     static Epoch parse(const QString &datetime);
+    /** Computes the decimal epoch as the day of year a  */
     double toEpoch() const;
+    /** Encodes the Epoch as YYYY-MM-DDThh:mm:ss.uuuuuu. */
     QString toString() const;
   };
 
@@ -69,41 +86,68 @@ public:
   unsigned int revolutionNumber() const;
 
 public:
+  /** Constructs a orbital element from a CelesTrak JSON object. */
   static OrbitalElement fromCelesTrak(const QJsonObject &obj);
 
 protected:
+  /** NORAD id of the satellite. */
   unsigned int _id;
+  /** Desriptive name of the satellite. */
   QString _name;
+  /** The epoch. */
   Epoch _epoch;
+  /** Mean motion. */
   double _meanMotion;
+  /** First derivative of the mean motion. */
   double _meanMotionDerivative;
+  /** Inclination. */
   double _inclination;
+  /** Right ascension of the ascending node. */
   double _ascension;
+  /** Eccentricity. */
   double _eccentricity;
+  /** Argument of perigee. */
   double _perigee;
+  /** Mean anomaly. */
   double _meanAnomaly;
+  /** The revolution number. */
   unsigned int _revolutionNumber;
 };
 
 
 
+/** Downloads and updates a database of orbital elements from CelesTrak.
+ * @ingroup sat */
 class OrbitalElementsDatabase: public QAbstractTableModel
 {
   Q_OBJECT
 
 public:
+  /** Constructs a orbital element database.
+   * @param autoLoad [in] If @c true, the database gets downloaded and loaded automatically.
+   * @param updatePeriodDays [in] Specifies the max age of the local database cache in days.
+   * @param parent [in] Specifies the QObject parent. */
   explicit OrbitalElementsDatabase(bool autoLoad, unsigned int updatePeriodDays=7, QObject *parent=nullptr);
 
+  /** @c returns @c true if the database contains a satellite with the given NORAD id. */
   bool contains(unsigned int id) const;
+  /** Retunrs the orbital elements for the satellite with the given NORAD id. */
   OrbitalElement getById(unsigned int id) const;
+  /** Returns the i-th orbital element. */
   const OrbitalElement &getAt(unsigned int idx) const;
+  /** Returns the i-th orbital element. */
   OrbitalElement &getAt(unsigned int idx);
 
+  /** Returns the current age of the cache. */
   unsigned int dbAge() const;
+  /** If needed, downloads the database and loads all received orbital elements. */
   void load();
 
+  /** Returns the number of elements in the database. */
   int rowCount(const QModelIndex &parent = QModelIndex()) const;
+  /** Returns the number of columns of the database table. */
   int columnCount(const QModelIndex &parent = QModelIndex()) const;
+  /** Returns a single cell of the database table. */
   QVariant data(const QModelIndex &index, int role) const;
 
 signals:
@@ -121,6 +165,7 @@ private slots:
   void downloadFinished(QNetworkReply *reply);
 
 protected:
+  /** Loads a database from the given filename. */
   bool load(const QString &filename);
 
 private:
diff --git a/lib/radioddity_codeplug.hh b/lib/radioddity_codeplug.hh
index cc720057..4da555d8 100644
--- a/lib/radioddity_codeplug.hh
+++ b/lib/radioddity_codeplug.hh
@@ -263,6 +263,7 @@ public:
       static constexpr Bit talkaround() { return {0x0033, 3}; }
       static constexpr Bit vox() { return {0x0033, 6}; }
       static constexpr Bit power() { return {0x0033, 7}; }
+      /// @endcond
     };
   };
 
diff --git a/lib/radioddity_extensions.hh b/lib/radioddity_extensions.hh
index 9f5f0072..96c9ebcb 100644
--- a/lib/radioddity_extensions.hh
+++ b/lib/radioddity_extensions.hh
@@ -38,6 +38,7 @@ public:
   Q_ENUM(Function)
 
 public:
+  /** Default constructor. */
   explicit RadioddityButtonSettingsExtension(QObject *parent=nullptr);
 
   ConfigItem *clone() const;
diff --git a/lib/satellitedatabase.cc b/lib/satellitedatabase.cc
index 6da5a565..3f2cfe72 100644
--- a/lib/satellitedatabase.cc
+++ b/lib/satellitedatabase.cc
@@ -25,7 +25,7 @@ Satellite::Satellite()
 }
 
 Satellite::Satellite(const OrbitalElement &orbit)
-  : OrbitalElement(orbit), _name(orbit.name()),
+  : OrbitalElement(orbit), _name(),
     _fmUplink(), _fmDownlink(), _fmUplinkTone(), _fmDownlinkTone(),
     _aprsUplink(), _aprsDownlink(), _aprsUplinkTone(), _aprsDownlinkTone(), _beacon()
 {
@@ -43,6 +43,7 @@ Satellite::setName(const QString &name) {
   _name = name.simplified();
 }
 
+
 const Frequency &
 Satellite::fmUplink() const {
   return _fmUplink;
diff --git a/lib/satellitedatabase.hh b/lib/satellitedatabase.hh
index 590ff4ef..95b73492 100644
--- a/lib/satellitedatabase.hh
+++ b/lib/satellitedatabase.hh
@@ -8,85 +8,141 @@
 #include "orbitalelementsdatabase.hh"
 
 
-
+/** Extends the @c OrbitalElement to include transponder information for a satellite.
+ *
+ * This represents a single user-curated satellite. The orbital elements are updated automatically,
+ * while the transponder information remains set by the user.
+ *
+ * @ingroup sat */
 class Satellite: public OrbitalElement
 {
 public:
+  /** Default constructor. */
   Satellite();
+  /** Constructor from orbital element. */
   Satellite(const OrbitalElement &orbit);
-
+  /** Copy constructor. */
   Satellite(const Satellite &sat) = default;
+  /** Copy assignment. */
   Satellite &operator =(const Satellite &other) = default;
 
+  /** Returns the name of the satellite. */
   const QString &name() const;
+  /** Sets the name of the satellite. */
   void setName(const QString &name);
 
+  /** Returns the FM uplink frequency. */
   const Frequency &fmUplink() const;
+  /** Sets the FM uplink frequency. */
   void setFMUplink(const Frequency &f);
+  /** Returns the FM downlink frequency. */
   const Frequency &fmDownlink() const;
+  /** Sets the FM downlink frequency. */
   void setFMDownlink(const Frequency &f);
+  /** Returns the FM uplink tone (i.e., TX tone). */
   const SelectiveCall &fmUplinkTone() const;
+  /** Returns the FM downlink tone (i.e., RX tone). */
   const SelectiveCall &fmDownlinkTone() const;
 
+  /** Returns the APRS uplink frequency. */
   const Frequency &aprsUplink() const;
+  /** Sets the APRS uplink frequency. */
   void setAPRSUplink(const Frequency &f);
+  /** Returns the APRS downlink frequency. */
   const Frequency &aprsDownlink() const;
+  /** Sets the APRS downlink frequency. */
   void setAPRSDownlink(const Frequency &f);
+  /** Returns the APRS uplink tone (i.e., TX tone). */
   const SelectiveCall &aprsUplinkTone() const;
+  /** Returns the APRS downlink tone (i.e., RX tone). */
   const SelectiveCall &aprsDownlinkTone() const;
 
+  /** Returns a beacon frequency. */
   const Frequency &beacon() const;
+  /** Sets a beacon frequency. */
   void setBeacon(const Frequency &f);
 
+  /** Serializes the satellite into a JSON object. */
   QJsonObject toJson() const;
 
 public:
+  /** Constructs a satellite from the given JSON object and orbital element database. */
   static Satellite fromJson(const QJsonObject &obj, const OrbitalElementsDatabase &db);
 
 protected:
+  /** Holds the name of the satellite. */
   QString _name;
+  /** Holds the FM uplink frequency. */
   Frequency _fmUplink;
+  /** Holds the FM downlink frequency. */
   Frequency _fmDownlink;
+  /** Holds the FM uplink tone. */
   SelectiveCall _fmUplinkTone;
+  /** Holds the FM downlink tone. */
   SelectiveCall _fmDownlinkTone;
+  /** Holds the APRS uplink frequency. */
   Frequency _aprsUplink;
+  /** Holds the APRS downlink frequency. */
   Frequency _aprsDownlink;
+  /** Holds the APRS uplink tone. */
   SelectiveCall _aprsUplinkTone;
+  /** Holds the APRS downlink tone. */
   SelectiveCall _aprsDownlinkTone;
+  /** Holds a beacon frequency. */
   Frequency _beacon;
 };
 
 
 
 /** A table holding all known satellites.
- * This table merges oribtal with transponder information. */
+ * This table merges oribtal with transponder information.
+ * @ingroup sat */
 class SatelliteDatabase : public QAbstractTableModel
 {
   Q_OBJECT
 
 public:
+  /** Constructs a new satellite database. */
   explicit SatelliteDatabase(unsigned int updatePeriodDays=7, QObject *parent = nullptr);
 
+  /** Returns the orbital element database. */
   const OrbitalElementsDatabase &orbitalElements() const;
+  /** Returns the orbital element database. */
   OrbitalElementsDatabase &orbitalElements();
+  /** Returns the transponder database. */
   const TransponderDatabase &transponders() const;
+  /** Returns the transponder database. */
   TransponderDatabase &transponders();
 
+  /** Returns the number of configured satellites. */
   unsigned int count() const;
+  /** Returns the i-th satellite. */
   const Satellite &getAt(unsigned int idx) const;
+  /** Appends a satellite. */
   void add(const Satellite &sat);
+  /** Removes one or more satellites. */
   bool removeRows(int row, int count, const QModelIndex &parent=QModelIndex());
 
+  /** Implements the QAbstractTableModel interface. Returns some flags for the given cell. */
   Qt::ItemFlags flags(const QModelIndex &index) const;
-  int rowCount(const QModelIndex &parent) const;
-  int columnCount(const QModelIndex &parent) const;
+  /** Implements the QAbstractTableModel interface.
+   * Returns the number of rows in the table. That is, the number of satellites. */
+  int rowCount(const QModelIndex &parent=QModelIndex()) const;
+  /** Implements the QAbstractTableModel interface. Returns the number of columns in the table. */
+  int columnCount(const QModelIndex &parent=QModelIndex()) const;
+  /** Implements the QAbstractTableModel interface. Returns the header labels. */
   QVariant headerData(int section, Qt::Orientation orientation, int role) const;
+  /** Implements the QAbstractTableModel interface. Returns the data for the cell. */
   QVariant data(const QModelIndex &index, int role) const;
+  /** Implements the QAbstractTableModel interface. Sets the data for a cell. */
   bool setData(const QModelIndex &index, const QVariant &value, int role);
 
 public slots:
+  /** Triggers a download of the orbital and transponder databases. */
   void update();
+  /** Loads the user-curated satellite database. */
   void load();
+  /** Saves the user-curated satellite database. */
   bool save(const ErrorStack &err = ErrorStack()) const;
 
 signals:
@@ -98,7 +154,9 @@ signals:
 private:
   /** Holds all sattellites sorted by their catalog number. */
   QVector<Satellite>  _satellites;
+  /** Holds the orbital element database. */
   OrbitalElementsDatabase _orbitalElements;
+  /** Holds the transponder database. */
   TransponderDatabase _transponders;
 };
 
diff --git a/lib/signaling.hh b/lib/signaling.hh
index cd8f5457..c24b786c 100644
--- a/lib/signaling.hh
+++ b/lib/signaling.hh
@@ -12,6 +12,7 @@
 struct SelectiveCall
 {
 protected:
+  /** Type of the subtone. */
   enum class Type {
     None, CTCSS, DCS
   };
@@ -78,10 +79,10 @@ protected:
   };
 
 protected:
+  /** Fixed table of standard values. */
   static QVector<SelectiveCall> _standard;
 };
 
-
 Q_DECLARE_METATYPE(SelectiveCall)
 
 
diff --git a/lib/transponderdatabase.hh b/lib/transponderdatabase.hh
index 79df6796..8fe50e79 100644
--- a/lib/transponderdatabase.hh
+++ b/lib/transponderdatabase.hh
@@ -7,70 +7,109 @@
 #include "frequency.hh"
 
 
-
+/** Represents a single transponder of a satellite. */
 struct Transponder
 {
 
 public:
+  /** Possible transponder types. */
   enum class Type {
-    Transponder,
-    Transmitter
+    Transponder,  ///< Proper transponder (repeater).
+    Transmitter   ///< Just a transmitter (beacon).
   };
 
+  /** Possible transponder modes. */
   enum class Mode {
-    FM, CW, APRS, BPSK
+    FM,   ///< Plain FM.
+    CW,   ///< Simple CW.
+    APRS, ///< AFSK APRS.
+    BPSK  ///< BPSK.
   };
 
 public:
+  /** Default constructor. */
   Transponder();
 
+  /** Returns @c true, if the transponder is valid.
+   * I.e., it is associated with a satellite. */
   bool isValid() const;
 
+  /** Returns the NORAD id of the associated satellite. */
   unsigned int satellite() const;
+  /** Returns the transponder type. */
   Type type() const;
+  /** Returns the transponder mode. */
   Mode mode() const;
 
+  /** Returns a descriptive name of the transponder. */
   const QString &name() const;
 
+  /** Returns the uplink frequency, if there is one.
+   * An upload frequency is usually missing, if the type is @c Type::Transmitter. */
   const Frequency &uplink() const;
+  /** Retruns the downlink frequency. */
   const Frequency &downlink() const;
 
 public:
+  /** Parses a transponder from the given SatNOGS JSON object. */
   static Transponder fromSATNOGS(const QJsonObject &obj);
 
 protected:
+  /** Holds the NORAD id of the satellite. */
   unsigned int _satellite;
+  /** Holds the transponder type. */
   Type _type;
+  /** Holds the transponder mode. */
   Mode _mode;
+  /** Holds the name. */
   QString _name;
+  /** Holds the downlink frequency. */
   Frequency _downlink;
+  /** Holds the uplink frequency. */
   Frequency _uplink;
 };
 
 
 
+/** Implements the database of all known transponder.
+ * @ingroup sat */
 class TransponderDatabase : public QAbstractTableModel
 {
   Q_OBJECT
 
 public:
+  /** Just a const iterator over all transponder. */
   typedef QVector<Transponder>::const_iterator const_iterator;
 
 public:
+  /** Constructor.
+   * @param autoLoad If @c true, the transponder information gets downloaded and loaded
+   *        automatically.
+   * @param updatePeriod Specifies the maximum age of the cache in days.
+   * @param parent The QObject parent. */
   explicit TransponderDatabase(bool autoLoad, unsigned int updatePeriod = 7, QObject *parent = nullptr);
 
+  /** The current age of the cache. */
   unsigned int dbAge() const;
 
+  /** Returns the i-th transponder. */
   const Transponder &getAt(unsigned int idx) const;
 
+  /** Implements the QAbstractTableModel interface.
+   * Returns the number of rows in the table. That is, the number of transponder. */
   int rowCount(const QModelIndex &parent) const;
+  /** Implements the QAbstractTableModel interface. Returns the number of columns in the table. */
   int columnCount(const QModelIndex &parent) const;
+  /** Implements the QAbstractTableModel interface. Returns the data for the cell. */
   QVariant data(const QModelIndex &index, int role) const;
 
+  /** Returns an iterator, pointing at the first transponder. */
   const_iterator begin() const;
+  /** Returns an iterator, pointing right after the last transponder. */
   const_iterator end() const;
 
 public slots:
+  /** Downloads and loads all transponder information. */
   void load();
 
 signals:
@@ -88,6 +127,7 @@ private slots:
   void downloadFinished(QNetworkReply *reply);
 
 protected:
+  /** Loads the transponder information from the given file. */
   bool load(const QString &filename);
 
 private:
diff --git a/lib/tyt_codeplug.hh b/lib/tyt_codeplug.hh
index cf4b460d..1d765513 100644
--- a/lib/tyt_codeplug.hh
+++ b/lib/tyt_codeplug.hh
@@ -1185,6 +1185,7 @@ public:
   public:
     /** Some Limits. */
     struct Limit {
+      /** The maximum number of messages in a bank. */
       static constexpr unsigned int messages() { return 50; }
     };
   };