Capture comments like JO21sv -> IO70vt. Closes #121

data/spot.py

@@ -325,6 +325,19 @@ class Spot:
                         self.propagation_mode = mode_tag
                         logging.info("Seen a new propagation mode tag not yet in the system: %s", mode_tag)
 
+        # Parse "de_grid -> dx_grid" structures from the comment
+        if self.comment:
+            grid_mode_grid_match = re.search(
+                r'\b([A-Ra-r]{2}\d{2}(?:[A-Xa-x]{2}(?:\d{2})?)?)\s*->\s*([A-Ra-r]{2}\d{2}(?:[A-Xa-x]{2}(?:\d{2})?)?)\b',
+                self.comment)
+            if grid_mode_grid_match:
+                # regex matches, so extract grids:
+                if not self.dx_grid:
+                    self.dx_grid = grid_mode_grid_match.group(1).upper()
+                    self.dx_location_source = "SPOT"
+                if not self.de_grid:
+                    self.de_grid = grid_mode_grid_match.group(2).upper()
+
         # DX Grid to lat/lon and vice versa in case one is missing
         if self.dx_grid and not self.dx_latitude:
             try: