diff --git a/lib/microwaveprop_web/live/beacon_live/show.ex b/lib/microwaveprop_web/live/beacon_live/show.ex
index afde66cc..9ea631f9 100644
--- a/lib/microwaveprop_web/live/beacon_live/show.ex
+++ b/lib/microwaveprop_web/live/beacon_live/show.ex
@@ -60,14 +60,21 @@ defmodule MicrowavepropWeb.BeaconLive.Show do
       </div>
 
       <div class="mb-2 flex items-center justify-between flex-wrap gap-2">
-        <label class="label cursor-pointer gap-2 py-0">
+        <label class={[
+          "label gap-2 py-0",
+          if(@coverage_supported, do: "cursor-pointer", else: "cursor-not-allowed opacity-60")
+        ]}>
           <input
             type="checkbox"
             class="toggle toggle-sm toggle-primary"
             checked={@show_coverage}
-            phx-click="toggle_coverage"
+            disabled={not @coverage_supported}
+            phx-click={if @coverage_supported, do: "toggle_coverage"}
           />
           <span class="label-text text-sm">Show estimated current coverage</span>
+          <span :if={not @coverage_supported} class="label-text-alt text-xs opacity-70">
+            (5.76 GHz and up only — atmospheric loss dominates on microwave bands)
+          </span>
         </label>
       </div>
 
@@ -161,17 +168,28 @@ defmodule MicrowavepropWeb.BeaconLive.Show do
      |> assign(:page_title, "Beacon")
      |> assign(:beacon, beacon)
      |> assign(:show_coverage, false)
+     |> assign(:coverage_supported, coverage_supported?(beacon))
      |> assign(:estimate, RangeEstimate.estimate(beacon))}
   end
 
+  # Estimated current coverage only makes sense from 5.76 GHz upward,
+  # where atmospheric attenuation meaningfully shapes the reach. Below
+  # that the free-space-loss-dominated map is misleading.
+  defp coverage_supported?(%{frequency_mhz: mhz}) when is_number(mhz), do: mhz >= 5760
+  defp coverage_supported?(_), do: false
+
   @impl true
   def handle_event("toggle_coverage", _params, socket) do
-    show = not socket.assigns.show_coverage
+    if socket.assigns.coverage_supported do
+      show = not socket.assigns.show_coverage
 
-    {:noreply,
-     socket
-     |> assign(:show_coverage, show)
-     |> push_event("toggle_coverage", %{show: show})}
+      {:noreply,
+       socket
+       |> assign(:show_coverage, show)
+       |> push_event("toggle_coverage", %{show: show})}
+    else
+      {:noreply, socket}
+    end
   end
 
   def handle_event("approve", _params, socket) do
@@ -189,9 +207,13 @@ defmodule MicrowavepropWeb.BeaconLive.Show do
 
   @impl true
   def handle_info({:updated, %Beacon{id: id} = beacon}, %{assigns: %{beacon: %{id: id}}} = socket) do
+    supported = coverage_supported?(beacon)
+
     {:noreply,
      socket
      |> assign(:beacon, beacon)
+     |> assign(:coverage_supported, supported)
+     |> assign(:show_coverage, socket.assigns.show_coverage and supported)
      |> assign(:estimate, RangeEstimate.estimate(beacon))}
   end