diff --git a/internal/cluster/cluster.go b/internal/cluster/cluster.go
index 2616a64..f28cce9 100644
--- a/internal/cluster/cluster.go
+++ b/internal/cluster/cluster.go
@@ -18,6 +18,8 @@ import (
 	"strings"
 	"sync"
 	"time"
+
+	"hamlog/internal/applog"
 )
 
 // ServerConfig is the persisted shape of one cluster node. Mirrors the
@@ -106,6 +108,7 @@ type session struct {
 	doneCh    chan struct{}
 	stopped   bool // guards against double-stop on the same session
 	spotsCnt  int
+	dbgN      int // diagnostic: how many raw lines logged this connection
 }
 
 // Manager owns N sessions, one per enabled server. Safe for concurrent
@@ -392,10 +395,31 @@ func (s *session) runOnce() (time.Time, error) {
 			return connectedAt, fmt.Errorf("read: %w", err)
 		}
 		line = strings.TrimRight(line, "\r\n")
+		// Strip terminal BELLs (\a) and other control bytes that some nodes
+		// (e.g. F5LEN) append to spot lines — "DX de …0935Z KN04\a\a" — which
+		// would otherwise break the parser's end-of-line anchor. Tabs → spaces.
+		line = strings.Map(func(r rune) rune {
+			if r == '\t' {
+				return ' '
+			}
+			if r < 0x20 || r == 0x7f {
+				return -1
+			}
+			return r
+		}, line)
 		if line == "" {
 			continue
 		}
 
+		// Safety net: warn (rate-limited) about DX lines the parser still can't
+		// read, so a future format drift is visible in the log.
+		if strings.Contains(line, "DX de") && s.dbgN < 10 {
+			if _, ok := parseSpot(line); !ok {
+				s.dbgN++
+				applog.Printf("cluster[%s] UNPARSED spot: %q", s.cfg.Name, line)
+			}
+		}
+
 		// Login on explicit prompt.
 		if !loginSent && s.login != "" && isLoginPrompt(line) {
 			_, _ = conn.Write([]byte(s.login + "\r\n"))