diff --git a/lib/microwaveprop/radio/contact.ex b/lib/microwaveprop/radio/contact.ex
index f5b2f570..0ff612e7 100644
--- a/lib/microwaveprop/radio/contact.ex
+++ b/lib/microwaveprop/radio/contact.ex
@@ -39,13 +39,14 @@ defmodule Microwaveprop.Radio.Contact do
 
     field :user_submitted, :boolean, default: false
     field :submitter_email, :string
+    field :user_id, :binary_id
     field :flagged_invalid, :boolean, default: false
 
     timestamps(type: :utc_datetime)
   end
 
   @required_fields ~w(station1 station2 qso_timestamp mode band)a
-  @optional_fields ~w(grid1 grid2 pos1 pos2 distance_km)a
+  @optional_fields ~w(grid1 grid2 pos1 pos2 distance_km user_id)a
 
   def changeset(contact, attrs) do
     contact
@@ -53,14 +54,16 @@ defmodule Microwaveprop.Radio.Contact do
     |> validate_required(@required_fields)
   end
 
-  @submission_fields ~w(station1 station2 qso_timestamp mode band grid1 grid2 submitter_email)a
+  @submission_fields ~w(station1 station2 qso_timestamp mode band grid1 grid2 submitter_email user_id)a
+  @submission_required ~w(station1 station2 qso_timestamp mode band grid1 grid2)a
   @allowed_modes ~w(CW SSB FM FT8 FT4)
   @allowed_bands Enum.map(~w(1296 2304 3456 5760 10000 24000 47000 68000 75000 122000 134000 241000), &Decimal.new/1)
 
   def submission_changeset(contact, attrs) do
     contact
     |> cast(attrs, @submission_fields)
-    |> validate_required(@submission_fields)
+    |> validate_required(@submission_required)
+    |> validate_user_or_email()
     |> sanitize_callsign(:station1)
     |> sanitize_callsign(:station2)
     |> sanitize_grid(:grid1)
@@ -71,12 +74,33 @@ defmodule Microwaveprop.Radio.Contact do
     |> validate_grid_format(:grid2)
     |> validate_inclusion(:mode, @allowed_modes)
     |> validate_inclusion(:band, @allowed_bands)
-    |> validate_format(:submitter_email, ~r/^[^\s<>]+@[^\s<>]+\.[^\s<>]+$/)
+    |> validate_email_format()
     |> validate_length(:submitter_email, max: 254)
     |> validate_length(:station1, max: 20)
     |> validate_length(:station2, max: 20)
   end
 
+  # Either a user_id (logged-in submitter) or a submitter_email (anonymous)
+  # must be present so we know who submitted the contact.
+  defp validate_user_or_email(changeset) do
+    user_id = get_field(changeset, :user_id)
+    email = get_field(changeset, :submitter_email)
+
+    if user_id || (email && email != "") do
+      changeset
+    else
+      add_error(changeset, :submitter_email, "can't be blank")
+    end
+  end
+
+  defp validate_email_format(changeset) do
+    case get_field(changeset, :submitter_email) do
+      nil -> changeset
+      "" -> changeset
+      _email -> validate_format(changeset, :submitter_email, ~r/^[^\s<>]+@[^\s<>]+\.[^\s<>]+$/)
+    end
+  end
+
   # Strip whitespace and upcase callsigns
   defp sanitize_callsign(changeset, field) do
     case get_change(changeset, field) do
diff --git a/lib/microwaveprop_web/live/submit_live.ex b/lib/microwaveprop_web/live/submit_live.ex
index a09ba88e..6d566046 100644
--- a/lib/microwaveprop_web/live/submit_live.ex
+++ b/lib/microwaveprop_web/live/submit_live.ex
@@ -66,6 +66,8 @@ defmodule MicrowavepropWeb.SubmitLive do
     if recently_submitted?(socket) do
       {:noreply, put_flash(socket, :error, "Please wait before submitting another contact.")}
     else
+      contact_params = merge_user_params(contact_params, socket)
+
       case Radio.create_contact(contact_params) do
         {:ok, contact} ->
           ContactWeatherEnqueueWorker.enqueue_for_contact(contact)
@@ -82,8 +84,14 @@ defmodule MicrowavepropWeb.SubmitLive do
     end
   end
 
-  def handle_event("upload_csv", %{"submitter_email" => email}, socket) do
-    if String.trim(email) == "" do
+  def handle_event("upload_csv", params, socket) do
+    email =
+      case current_user(socket.assigns) do
+        %{email: user_email} -> user_email
+        _ -> params |> Map.get("submitter_email", "") |> String.trim()
+      end
+
+    if email == "" do
       {:noreply, put_flash(socket, :error, "Email is required for CSV upload")}
     else
       uploaded_contents =
@@ -144,6 +152,18 @@ defmodule MicrowavepropWeb.SubmitLive do
     end
   end
 
+  defp merge_user_params(params, socket) do
+    case current_user(socket.assigns) do
+      %{id: user_id, email: user_email} ->
+        params
+        |> Map.put("user_id", user_id)
+        |> Map.put("submitter_email", user_email)
+
+      _ ->
+        params
+    end
+  end
+
   @impl true
   def render(assigns) do
     ~H"""
@@ -156,10 +176,10 @@ defmodule MicrowavepropWeb.SubmitLive do
       <div class="bg-info/10 border border-info/30 rounded-box p-4 mb-6 text-sm leading-relaxed">
         <p class="font-semibold text-info mb-1">Every contact matters</p>
         <p>
-          Our propagation model improves with real-world data. Each verified microwave contact
+          Our propagation model improves with real-world data. Each verified contact
           you submit is matched against atmospheric conditions at the time of your contact,
-          helping us calibrate predictions for all bands from 10 GHz to 241 GHz. The more contacts
-          we have, the better our forecasts get for everyone.
+          helping us calibrate predictions for all amateur bands from 902 MHz and up. The
+          more contacts we have, the better our forecasts get for everyone.
         </p>
       </div>
 
@@ -199,7 +219,12 @@ defmodule MicrowavepropWeb.SubmitLive do
       </div>
 
       <%= if @active_tab == :single do %>
-        <.single_contact_form form={@form} band_options={@band_options} mode_options={@mode_options} />
+        <.single_contact_form
+          form={@form}
+          band_options={@band_options}
+          mode_options={@mode_options}
+          current_user={current_user(assigns)}
+        />
       <% else %>
         <%= cond do %>
           <% @csv_result -> %>
@@ -207,13 +232,17 @@ defmodule MicrowavepropWeb.SubmitLive do
           <% @csv_preview -> %>
             <.csv_preview preview={@csv_preview} />
           <% true -> %>
-            <.csv_upload_form uploads={@uploads} />
+            <.csv_upload_form uploads={@uploads} current_user={current_user(assigns)} />
         <% end %>
       <% end %>
     </Layouts.app>
     """
   end
 
+  # In-template variant — takes an assigns map directly (not a socket).
+  defp current_user(%{current_scope: %{user: %{} = user}}), do: user
+  defp current_user(_), do: nil
+
   defp single_contact_form(assigns) do
     ~H"""
     <.form for={@form} id="contact-form" phx-change="validate" phx-submit="save" class="space-y-4">
@@ -262,13 +291,21 @@ defmodule MicrowavepropWeb.SubmitLive do
         <.input field={@form[:qso_timestamp]} type="datetime-local" label="Timestamp (UTC)" required />
       </div>
 
-      <.input
-        field={@form[:submitter_email]}
-        type="email"
-        label="Your Email"
-        placeholder="you@example.com"
-        required
-      />
+      <%= if @current_user do %>
+        <input
+          type="hidden"
+          name="contact[submitter_email]"
+          value={@current_user.email}
+        />
+      <% else %>
+        <.input
+          field={@form[:submitter_email]}
+          type="email"
+          label="Your Email"
+          placeholder="you@example.com"
+          required
+        />
+      <% end %>
 
       <div class="mt-6">
         <.button phx-disable-with="Submitting..." class="btn btn-primary btn-lg w-full sm:w-auto">
@@ -311,18 +348,22 @@ defmodule MicrowavepropWeb.SubmitLive do
           </label>
         </div>
 
-        <div class="fieldset mb-2">
-          <label>
-            <span class="label mb-1">Your Email</span>
-            <input
-              type="email"
-              name="submitter_email"
-              class="w-full input"
-              placeholder="you@example.com"
-              value=""
-            />
-          </label>
-        </div>
+        <%= if @current_user do %>
+          <input type="hidden" name="submitter_email" value={@current_user.email} />
+        <% else %>
+          <div class="fieldset mb-2">
+            <label>
+              <span class="label mb-1">Your Email</span>
+              <input
+                type="email"
+                name="submitter_email"
+                class="w-full input"
+                placeholder="you@example.com"
+                value=""
+              />
+            </label>
+          </div>
+        <% end %>
 
         <div class="mt-6">
           <button type="submit" class="btn btn-primary btn-lg w-full sm:w-auto">
diff --git a/priv/repo/migrations/20260409175343_add_user_id_to_contacts.exs b/priv/repo/migrations/20260409175343_add_user_id_to_contacts.exs
new file mode 100644
index 00000000..ea51b366
--- /dev/null
+++ b/priv/repo/migrations/20260409175343_add_user_id_to_contacts.exs
@@ -0,0 +1,11 @@
+defmodule Microwaveprop.Repo.Migrations.AddUserIdToContacts do
+  use Ecto.Migration
+
+  def change do
+    alter table(:contacts) do
+      add :user_id, references(:users, type: :binary_id, on_delete: :nilify_all)
+    end
+
+    create index(:contacts, [:user_id])
+  end
+end