diff --git a/app.go b/app.go
index 7556767..3cc99af 100644
--- a/app.go
+++ b/app.go
@@ -5844,8 +5844,20 @@ func (a *App) TestPTT(cfg AudioSettings) error {
 	if err := a.pttKey(cfg); err != nil {
 		return err
 	}
+	// Hold long enough to be observable. OmniRig is async and coalesces rapid
+	// writes to the same parameter: it stores the desired Tx value and flushes
+	// on its own poll timer, so a key (PM_TX) followed too quickly by an unkey
+	// (PM_RX) can land in ONE flush cycle — OmniRig then sends only the last
+	// value (PM_RX) and the rig never actually transmits (while an already-MOX'd
+	// rig gets dropped by that lone PM_RX). A longer hold guarantees the key
+	// command is sent and held before the release. Serial RTS/DTR is instant,
+	// so it keeps the short window.
+	hold := 600 * time.Millisecond
+	if cfg.PTTMethod == "cat" {
+		hold = 1500 * time.Millisecond
+	}
 	gen := a.pttGenNow()
-	go func() { time.Sleep(600 * time.Millisecond); a.unkeyIfCurrent(gen) }()
+	go func() { time.Sleep(hold); a.unkeyIfCurrent(gen) }()
 	return nil
 }
 
diff --git a/internal/cat/omnirig.go b/internal/cat/omnirig.go
index 14745ee..2046934 100644
--- a/internal/cat/omnirig.go
+++ b/internal/cat/omnirig.go
@@ -414,6 +414,16 @@ func (o *OmniRig) SetPTT(on bool) error {
 		debugLog.Printf("OmniRig.SetPTT error: %v", err)
 		return fmt.Errorf("set Tx=%s: %w", name, err)
 	}
+	// Read the Tx param straight back. OmniRig is async — this may still show the
+	// previous value for a poll cycle — but if a key/unkey NEVER changes it, the
+	// write was coalesced or the rig isn't honouring PM_TX/PM_RX (wrong .ini).
+	if v, err := oleutil.GetProperty(o.rig, "Tx"); err == nil {
+		txState := "PM_RX"
+		if v.Val&pmTX != 0 {
+			txState = "PM_TX"
+		}
+		debugLog.Printf("OmniRig.SetPTT: Tx readback = 0x%X (%s)", v.Val, txState)
+	}
 	return nil
 }