Partial fix for mypy issues

providers/spot/tiles.py

@@ -90,22 +90,25 @@ class Tiles(HTTPSpotProvider):
     def submit_spot(self, spot: Spot, credentials: dict[str, str]) -> None:
         # Tiles on the air currently only supports *self* spots
         if spot.dx_call == spot.de_call:
+            if not spot.freq:
+                raise RuntimeError("The Tiles on the Air API requires a frequency to be set.")
+
             # Figure out a valid mode. Borrowed this from PoLo :)
             # https://github.com/ham2k/app-polo/blob/main/src/extensions/activities/sota/SOTAPostSelfSpot.js
             if spot.mode:
-                mode = spot.mode
-                if mode not in self.VALID_MODES:
-                    if mode == "OLIVIA":
-                        mode = "Olivia"
-                    elif mode == "JS8":
-                        mode = "JS8Call"
+                mode_str: str = spot.mode.value
+                if spot.mode not in self.VALID_MODES:
+                    if spot.mode == "OLIVIA":
+                        mode_str = "Olivia"
+                    elif spot.mode == "JS8":
+                        mode_str = "JS8Call"
                     else:
-                        mode = "Other"
+                        mode_str = "Other"
 
                 body = {
                     "call_sign": spot.dx_call,
                     "frequency": str(spot.freq / 1000000.0),
-                    "mode": mode or "",
+                    "mode": mode_str or "",
                     "grid": spot.dx_grid or "",
                     "comment": spot.comment or "",
                     "lat": spot.dx_latitude or None,