diff --git a/app/repository/contacts.py b/app/repository/contacts.py
index 3af13c7..b5e257b 100644
--- a/app/repository/contacts.py
+++ b/app/repository/contacts.py
@@ -215,6 +215,19 @@ class ContactRepository:
         )
         await db.conn.commit()
 
+    @staticmethod
+    async def clear_on_radio_except(keep_keys: list[str]) -> None:
+        """Set on_radio=False for all contacts NOT in keep_keys."""
+        if not keep_keys:
+            await db.conn.execute("UPDATE contacts SET on_radio = 0 WHERE on_radio = 1")
+        else:
+            placeholders = ",".join("?" * len(keep_keys))
+            await db.conn.execute(
+                f"UPDATE contacts SET on_radio = 0 WHERE on_radio = 1 AND public_key NOT IN ({placeholders})",
+                keep_keys,
+            )
+        await db.conn.commit()
+
     @staticmethod
     async def delete(public_key: str) -> None:
         normalized = public_key.lower()
diff --git a/app/routers/channels.py b/app/routers/channels.py
index a14c428..1535d5e 100644
--- a/app/routers/channels.py
+++ b/app/routers/channels.py
@@ -127,4 +127,9 @@ async def delete_channel(key: str) -> dict:
     """
     logger.info("Deleting channel %s from database", key)
     await ChannelRepository.delete(key)
+
+    from app.websocket import broadcast_event
+
+    broadcast_event("channel_deleted", {"key": key})
+
     return {"status": "ok"}
diff --git a/app/routers/contacts.py b/app/routers/contacts.py
index defb331..0d4ee03 100644
--- a/app/routers/contacts.py
+++ b/app/routers/contacts.py
@@ -271,16 +271,21 @@ async def sync_contacts_from_radio() -> dict:
     contacts = result.payload
     count = 0
 
+    synced_keys: list[str] = []
     for public_key, contact_data in contacts.items():
         lower_key = public_key.lower()
         await ContactRepository.upsert(
             Contact.from_radio_dict(lower_key, contact_data, on_radio=True)
         )
+        synced_keys.append(lower_key)
         claimed = await MessageRepository.claim_prefix_messages(lower_key)
         if claimed > 0:
             logger.info("Claimed %d prefix DM message(s) for contact %s", claimed, public_key[:12])
         count += 1
 
+    # Clear on_radio for contacts not found on the radio
+    await ContactRepository.clear_on_radio_except(synced_keys)
+
     logger.info("Synced %d contacts from radio", count)
     return {"synced": count}
 
@@ -368,6 +373,10 @@ async def delete_contact(public_key: str) -> dict:
     await ContactRepository.delete(contact.public_key)
     logger.info("Deleted contact %s", contact.public_key[:12])
 
+    from app.websocket import broadcast_event
+
+    broadcast_event("contact_deleted", {"public_key": contact.public_key})
+
     return {"status": "ok"}
 
 
diff --git a/app/routers/messages.py b/app/routers/messages.py
index 2e999bc..72bf7b2 100644
--- a/app/routers/messages.py
+++ b/app/routers/messages.py
@@ -399,6 +399,7 @@ async def resend_channel_message(
             sender_timestamp=now,
             received_at=now,
             outgoing=True,
+            sender_name=radio_name or None,
         )
         if new_msg_id is None:
             # Timestamp-second collision (same text+channel within the same second).
diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index f470a3e..73ab1ab 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -287,6 +287,14 @@ export function App() {
       onContact: (contact: Contact) => {
         setContacts((prev) => mergeContactIntoList(prev, contact));
       },
+      onContactDeleted: (publicKey: string) => {
+        setContacts((prev) => prev.filter((c) => c.public_key !== publicKey));
+        messageCache.remove(publicKey);
+      },
+      onChannelDeleted: (key: string) => {
+        setChannels((prev) => prev.filter((c) => c.key !== key));
+        messageCache.remove(key);
+      },
       onRawPacket: (packet: RawPacket) => {
         setRawPackets((prev) => appendRawPacketUnique(prev, packet, MAX_RAW_PACKETS));
       },
@@ -306,6 +314,7 @@ export function App() {
       setConfig,
       activeConversationRef,
       setContacts,
+      setChannels,
       triggerReconcile,
       refreshUnreads,
       fetchAllContacts,
diff --git a/frontend/src/useWebSocket.ts b/frontend/src/useWebSocket.ts
index c1d6505..5269468 100644
--- a/frontend/src/useWebSocket.ts
+++ b/frontend/src/useWebSocket.ts
@@ -20,6 +20,8 @@ interface UseWebSocketOptions {
   onHealth?: (health: HealthStatus) => void;
   onMessage?: (message: Message) => void;
   onContact?: (contact: Contact) => void;
+  onContactDeleted?: (publicKey: string) => void;
+  onChannelDeleted?: (key: string) => void;
   onRawPacket?: (packet: RawPacket) => void;
   onMessageAcked?: (messageId: number, ackCount: number, paths?: MessagePath[]) => void;
   onError?: (error: ErrorEvent) => void;
@@ -103,6 +105,12 @@ export function useWebSocket(options: UseWebSocketOptions) {
           case 'contact':
             handlers.onContact?.(msg.data as Contact);
             break;
+          case 'contact_deleted':
+            handlers.onContactDeleted?.((msg.data as { public_key: string }).public_key);
+            break;
+          case 'channel_deleted':
+            handlers.onChannelDeleted?.((msg.data as { key: string }).key);
+            break;
           case 'raw_packet':
             handlers.onRawPacket?.(msg.data as RawPacket);
             break;