diff --git a/priv/repo/migrations/20260331143209_add_propagation_scores_viewport_index.exs b/priv/repo/migrations/20260331143209_add_propagation_scores_viewport_index.exs
new file mode 100644
index 00000000..5bae93a2
--- /dev/null
+++ b/priv/repo/migrations/20260331143209_add_propagation_scores_viewport_index.exs
@@ -0,0 +1,14 @@
+defmodule Microwaveprop.Repo.Migrations.AddPropagationScoresViewportIndex do
+  use Ecto.Migration
+
+  def change do
+    # Covering index for the map viewport query:
+    # SELECT lat, lon, score WHERE band_mhz = X AND valid_time = Y
+    #   AND lat BETWEEN a AND b AND lon BETWEEN c AND d
+    # INCLUDE (score) avoids heap lookups — index-only scan
+    create index(:propagation_scores, [:band_mhz, :valid_time, :lat, :lon],
+             include: [:score],
+             name: :propagation_scores_viewport_idx
+           )
+  end
+end
diff --git a/test/microwaveprop/terrain/elevation_client_test.exs b/test/microwaveprop/terrain/elevation_client_test.exs
index 3c87ad83..4cf61651 100644
--- a/test/microwaveprop/terrain/elevation_client_test.exs
+++ b/test/microwaveprop/terrain/elevation_client_test.exs
@@ -115,6 +115,8 @@ end
 defmodule Microwaveprop.Terrain.ElevationClientSrtmTest do
   use ExUnit.Case, async: false
 
+  import ExUnit.CaptureLog
+
   alias Microwaveprop.Terrain.ElevationClient
 
   @tiles_dir Path.expand("~/srtm/tiles")
@@ -153,9 +155,12 @@ defmodule Microwaveprop.Terrain.ElevationClientSrtmTest do
         Req.Test.json(conn, %{"elevation" => [200.0, 250.0, 180.0]})
       end)
 
-      assert {:ok, profile} =
-               ElevationClient.fetch_elevation_profile(32.9, -97.0, 30.3, -97.7, 2)
+      {result, _log} =
+        with_log(fn ->
+          ElevationClient.fetch_elevation_profile(32.9, -97.0, 30.3, -97.7, 2)
+        end)
 
+      assert {:ok, profile} = result
       assert length(profile) == 3
       assert hd(profile).elev == 200.0
     end
diff --git a/test/microwaveprop/terrain/srtm_test.exs b/test/microwaveprop/terrain/srtm_test.exs
index 680a98f6..a564fd01 100644
--- a/test/microwaveprop/terrain/srtm_test.exs
+++ b/test/microwaveprop/terrain/srtm_test.exs
@@ -1,6 +1,8 @@
 defmodule Microwaveprop.Terrain.SrtmTest do
   use ExUnit.Case, async: true
 
+  import ExUnit.CaptureLog
+
   alias Microwaveprop.Terrain.Srtm
 
   @tiles_dir Path.expand("~/srtm/tiles")
@@ -62,7 +64,9 @@ defmodule Microwaveprop.Terrain.SrtmTest do
         Plug.Conn.send_resp(conn, 404, "Not Found")
       end)
 
-      assert {:error, :not_available} = Srtm.download_tile(80.0, 0.0, tmp_dir)
+      capture_log(fn ->
+        assert {:error, :not_available} = Srtm.download_tile(80.0, 0.0, tmp_dir)
+      end)
     end
 
     test "returns error message on other HTTP status" do
@@ -75,7 +79,9 @@ defmodule Microwaveprop.Terrain.SrtmTest do
         Plug.Conn.send_resp(conn, 500, "Internal Server Error")
       end)
 
-      assert {:error, "SRTM download HTTP 500"} = Srtm.download_tile(32.0, -97.0, tmp_dir)
+      capture_log(fn ->
+        assert {:error, "SRTM download HTTP 500"} = Srtm.download_tile(32.0, -97.0, tmp_dir)
+      end)
     end
   end
 
@@ -105,7 +111,9 @@ defmodule Microwaveprop.Terrain.SrtmTest do
         Plug.Conn.send_resp(conn, 404, "Not Found")
       end)
 
-      assert {:error, :no_tile} = Srtm.lookup(80.0, 0.0, tmp_dir)
+      capture_log(fn ->
+        assert {:error, :no_tile} = Srtm.lookup(80.0, 0.0, tmp_dir)
+      end)
     end
   end
 
@@ -127,7 +135,9 @@ defmodule Microwaveprop.Terrain.SrtmTest do
         Plug.Conn.send_resp(conn, 404, "Not Found")
       end)
 
-      assert {:error, :no_tile} = Srtm.lookup(80.0, 0.0, @tiles_dir)
+      capture_log(fn ->
+        assert {:error, :no_tile} = Srtm.lookup(80.0, 0.0, @tiles_dir)
+      end)
     end
   end