diff --git a/sec-beidou-rtcm/src/main/java/com/imdroid/sideslope/rtkcluster/RtkClusterService.java b/sec-beidou-rtcm/src/main/java/com/imdroid/sideslope/rtkcluster/RtkClusterService.java
index ba650286..35a16fbb 100644
--- a/sec-beidou-rtcm/src/main/java/com/imdroid/sideslope/rtkcluster/RtkClusterService.java
+++ b/sec-beidou-rtcm/src/main/java/com/imdroid/sideslope/rtkcluster/RtkClusterService.java
@@ -288,15 +288,31 @@ public class RtkClusterService implements ApplicationRunner {
 
         private void dequeueLoop() {
             byte[] pending = null;
+            boolean lastWaitLogged = false;
             while (true) {
                 try {
+                    Socket out = outConn;
                     Socket sink = inConn;
-                    if (sink == null || sink.isClosed() || sink == outConn) {
-                        // wait for a valid IN sink before consuming queue
-                        ensureInCandidate();
-                        Thread.sleep(20);
+                    if (out == null) {
+                        // wait until OUT连接已就绪（rtkrcv 已输出首包/特征头）
+                        if (!lastWaitLogged) {
+                            LOGGER.info("Endpoint {} waiting for OUT to be ready before sending RTCM", port);
+                            lastWaitLogged = true;
+                        }
+                        Thread.sleep(50);
                         continue;
                     }
+                    if (sink == null || sink.isClosed() || sink == out) {
+                        // 等待有效的 IN 连接（且不能与 OUT 相同）
+                        if (!lastWaitLogged) {
+                            LOGGER.info("Endpoint {} waiting for IN to be ready before sending RTCM", port);
+                            lastWaitLogged = true;
+                        }
+                        ensureInCandidate();
+                        Thread.sleep(50);
+                        continue;
+                    }
+                    lastWaitLogged = false;
                     if (pending == null) {
                         pending = rtcmQueue.pollFirst(100, TimeUnit.MILLISECONDS);
                         if (pending == null) continue;