diff --git a/libraries/AP_Compass/AP_Compass.h b/libraries/AP_Compass/AP_Compass.h
index dc77d14823..fe68d386db 100644
--- a/libraries/AP_Compass/AP_Compass.h
+++ b/libraries/AP_Compass/AP_Compass.h
@@ -150,8 +150,8 @@ public:
     */
     MAV_RESULT handle_mag_cal_command(const mavlink_command_long_t &packet);
 
-    void send_mag_cal_progress(mavlink_channel_t chan);
-    void send_mag_cal_report(mavlink_channel_t chan);
+    bool send_mag_cal_progress(const class GCS_MAVLINK& link);
+    bool send_mag_cal_report(const class GCS_MAVLINK& link);
 
     // check if the compasses are pointing in the same direction
     bool consistent() const;
diff --git a/libraries/AP_Compass/AP_Compass_Calibration.cpp b/libraries/AP_Compass/AP_Compass_Calibration.cpp
index a9ff73d5d5..6e51e93ede 100644
--- a/libraries/AP_Compass/AP_Compass_Calibration.cpp
+++ b/libraries/AP_Compass/AP_Compass_Calibration.cpp
@@ -186,15 +186,17 @@ Compass::_accept_calibration_mask(uint8_t mask)
     return success;
 }
 
-void
-Compass::send_mag_cal_progress(mavlink_channel_t chan)
+bool Compass::send_mag_cal_progress(const GCS_MAVLINK& link)
 {
     uint8_t cal_mask = _get_cal_mask();
 
     for (uint8_t compass_id=0; compass_id<COMPASS_MAX_INSTANCES; compass_id++) {
         // ensure we don't try to send with no space available
-        if (!HAVE_PAYLOAD_SPACE(chan, MAG_CAL_PROGRESS)) {
-            return;
+        if (!HAVE_PAYLOAD_SPACE(link.get_chan(), MAG_CAL_PROGRESS)) {
+            // ideally we would only send one progress message per
+            // call.  If we don't return true here we may end up
+            // hogging *all* the bandwidth
+            return true;
         }
 
         auto& calibrator = _calibrator[compass_id];
@@ -205,27 +207,32 @@ Compass::send_mag_cal_progress(mavlink_channel_t chan)
             cal_status == COMPASS_CAL_RUNNING_STEP_TWO) {
             uint8_t completion_pct = calibrator.get_completion_percent();
             auto& completion_mask = calibrator.get_completion_mask();
-            Vector3f direction(0.0f,0.0f,0.0f);
+            const Vector3f direction;
             uint8_t attempt = _calibrator[compass_id].get_attempt();
 
             mavlink_msg_mag_cal_progress_send(
-                chan,
+                link.get_chan(),
                 compass_id, cal_mask,
                 cal_status, attempt, completion_pct, completion_mask,
                 direction.x, direction.y, direction.z
             );
         }
     }
+
+    return true;
 }
 
-void Compass::send_mag_cal_report(mavlink_channel_t chan)
+bool Compass::send_mag_cal_report(const GCS_MAVLINK& link)
 {
     uint8_t cal_mask = _get_cal_mask();
 
     for (uint8_t compass_id=0; compass_id<COMPASS_MAX_INSTANCES; compass_id++) {
         // ensure we don't try to send with no space available
-        if (!HAVE_PAYLOAD_SPACE(chan, MAG_CAL_REPORT)) {
-            return;
+        if (!HAVE_PAYLOAD_SPACE(link.get_chan(), MAG_CAL_REPORT)) {
+            // ideally we would only send one progress message per
+            // call.  If we don't return true here we may end up
+            // hogging *all* the bandwidth
+            return true;
         }
 
         uint8_t cal_status = _calibrator[compass_id].get_status();
@@ -238,7 +245,7 @@ void Compass::send_mag_cal_report(mavlink_channel_t chan)
             uint8_t autosaved = _cal_saved[compass_id];
 
             mavlink_msg_mag_cal_report_send(
-                chan,
+                link.get_chan(),
                 compass_id, cal_mask,
                 cal_status, autosaved,
                 fitness,
@@ -251,6 +258,7 @@ void Compass::send_mag_cal_report(mavlink_channel_t chan)
             );
         }
     }
+    return true;
 }
 
 bool