feat(cat): distinct Elecraft K3/K4 backend in the rig list

The Elecraft handling was buried in the Kenwood "data mode" option, so users
couldn't find it. Add "Elecraft K3/K4" as its own entry in the CAT backend
selector. It reuses the Kenwood-dialect transport and the Kenwood USB/network
settings (the K3 emulates the Kenwood command set — a separate transport would be
a near-total duplicate), with an `elecraft` flag on the client that forces
digital modes to DATA A (MD6+DT0) — no data-mode dropdown needed. RigState still
reports Backend "kenwood" so the CW-over-CAT keyer capability keeps working.

app.go

@@ -13140,6 +13140,21 @@ func (a *App) reloadCAT() {
 			kw.SetDataMode(s.KenwoodDataMode)
 			a.cat.Start(kw)
 		}
+	case "elecraft":
+		// Elecraft K3/K4: the Kenwood-dialect client with the Elecraft specifics on
+		// (digital modes → DATA A via MD6+DT0). Reuses the Kenwood port/baud/host
+		// settings — the K3 emulates the Kenwood command set, so a separate transport
+		// would be a near-total duplicate.
+		if h := strings.TrimSpace(s.KenwoodHost); h != "" {
+			kw := cat.NewKenwoodTCP(h, s.DigitalDefault)
+			kw.SetElecraft(true)
+			a.cat.Start(kw)
+		} else {
+			kw := cat.NewKenwood(s.KenwoodPort, s.KenwoodBaud, s.DigitalDefault)
+			kw.SetLowerLines(s.KenwoodLowLines)
+			kw.SetElecraft(true)
+			a.cat.Start(kw)
+		}
 	case "icom":
 		// Native Icom CI-V over the radio's USB serial port (local control).
 		// Same civ protocol the network backend reuses for remote.

changelog.json

@@ -10,7 +10,7 @@
       "UDP outbound: a QSO logged from WSJT-X / JTDX / MSHV (via the inbound UDP listener) is now forwarded to the outbound ADIF integrations too — previously only QSOs typed directly into OpsLog were re-emitted.",
       "Backup: with \"back up on every exit\", a new \"Keep every backup\" sub-option writes a distinct time-stamped file per exit (opslog-YYYY-MM-DD-HHMMSS.db) instead of overwriting the day's file. Rotation still keeps the newest N — raise it for more history.",
       "Awards editor: the PRIMARY QSOFIELDS search now has a Prefix field too (prepended to each found reference, e.g. captured 01 → D01) — previously only the OR fallback searches could add a prefix, so a DOK-style award couldn't match on its main rule.",
-      "CAT (Elecraft K3/K4): the DATA data-mode now sends MD6 + DT0 (DATA A), the sub-mode FT8 audio actually needs — MD6 alone could leave the rig in an FSK/PSK sub-mode where it keyed but sent no audio. Pick \"DATA A — MD6+DT0 (Elecraft K3/K4)\" under CAT data modes."
+      "CAT: new Elecraft K3/K4 backend in the rig list. Select it (it reuses the Kenwood USB/network settings) and digital modes automatically use DATA A (MD6+DT0) — the sub-mode FT8 audio needs, so the K3 no longer keys the transmitter without modulating."
     ],
     "fr": [
       "Sauvegarde : nouvelle option \"Sauvegarder à chaque fermeture\" (Réglages → Sauvegarde). Activée, OpsLog sauvegarde la base à chaque fois que tu quittes au lieu d'une seule fois par jour — les QSO d'une seconde session sont ainsi toujours pris.",
@@ -20,7 +20,7 @@
       "UDP sortant : un QSO enregistré depuis WSJT-X / JTDX / MSHV (via l'écouteur UDP entrant) est désormais aussi transmis aux intégrations ADIF sortantes — avant, seuls les QSO saisis directement dans OpsLog étaient réémis.",
       "Sauvegarde : avec \"sauvegarder à chaque fermeture\", une nouvelle sous-option \"Garder chaque sauvegarde\" écrit un fichier horodaté distinct par fermeture (opslog-AAAA-MM-JJ-HHMMSS.db) au lieu d'écraser le fichier du jour. La rotation garde les N plus récents — augmente-la pour plus d'historique.",
       "Éditeur de diplômes : la recherche PRINCIPALE QSOFIELDS a aussi un champ Préfixe (ajouté devant chaque référence trouvée, ex. 01 capturé → D01) — avant, seules les recherches OR de repli pouvaient ajouter un préfixe, empêchant un diplôme type DOK de matcher sur sa règle principale.",
-      "CAT (Elecraft K3/K4) : le mode data DATA envoie désormais MD6 + DT0 (DATA A), le sous-mode dont l'audio FT8 a réellement besoin — MD6 seul pouvait laisser le rig dans un sous-mode FSK/PSK où il passait en émission sans audio. Choisis \"DATA A — MD6+DT0 (Elecraft K3/K4)\" dans les modes data CAT."
+      "CAT : nouveau backend Elecraft K3/K4 dans la liste des rigs. Sélectionne-le (il réutilise les réglages USB/réseau Kenwood) et les modes numériques passent automatiquement en DATA A (MD6+DT0) — le sous-mode dont l'audio FT8 a besoin, donc le K3 ne passe plus en émission sans moduler."
     ]
   },
   {

frontend/src/components/SettingsModal.tsx

@@ -2527,6 +2527,7 @@ export function SettingsModal({ onClose, onSaved, initialSection, onMainPaneChan
                   <SelectItem value="flex">{t('cat.optFlex')}</SelectItem>
                   <SelectItem value="yaesu">{t('cat.optYaesu')}</SelectItem>
                   <SelectItem value="kenwood">{t('cat.optKenwood')}</SelectItem>
+                  <SelectItem value="elecraft">{t('cat.optElecraft')}</SelectItem>
                   <SelectItem value="xiegu">{t('cat.optXiegu')}</SelectItem>
                   <SelectItem value="icom">{t('cat.optIcom')}</SelectItem>
                   <SelectItem value="icom-net">{t('cat.optIcomNet')}</SelectItem>
@@ -2688,7 +2689,7 @@ export function SettingsModal({ onClose, onSaved, initialSection, onMainPaneChan
                   {t('cat.civTrace')}
                 </label>              </div>
             )}
-            {catCfg.backend === 'kenwood' && (
+            {(catCfg.backend === 'kenwood' || catCfg.backend === 'elecraft') && (
             <>
               <div className="space-y-1">
                 <Label>{t('cat.kenwoodPort')}</Label>
@@ -2725,16 +2726,21 @@ export function SettingsModal({ onClose, onSaved, initialSection, onMainPaneChan
                 </label>
                 <span className="text-xs text-muted-foreground">{t('cat.lowerLinesHint')}</span>
               </div>
-              <div className="space-y-1">
+              {catCfg.backend === 'kenwood' ? (
-                <Label>{t('cat.kwDataMode')}</Label>
+                <div className="space-y-1">
-                <Select value={(catCfg as any).kenwood_data_mode || 'usb'} onValueChange={(v) => setCatCfg((s) => ({ ...s, kenwood_data_mode: v } as any))}>
+                  <Label>{t('cat.kwDataMode')}</Label>
-                  <SelectTrigger className="h-8"><SelectValue /></SelectTrigger>
+                  <Select value={(catCfg as any).kenwood_data_mode || 'usb'} onValueChange={(v) => setCatCfg((s) => ({ ...s, kenwood_data_mode: v } as any))}>
-                  <SelectContent>
+                    <SelectTrigger className="h-8"><SelectValue /></SelectTrigger>
-                    <SelectItem value="usb">{t('cat.kwDataUsb')}</SelectItem>
+                    <SelectContent>
-                    <SelectItem value="data">{t('cat.kwDataMd6')}</SelectItem>
+                      <SelectItem value="usb">{t('cat.kwDataUsb')}</SelectItem>
-                    <SelectItem value="keep">{t('cat.kwDataKeep')}</SelectItem>
+                      <SelectItem value="data">{t('cat.kwDataMd6')}</SelectItem>
-                  </SelectContent>
+                      <SelectItem value="keep">{t('cat.kwDataKeep')}</SelectItem>
-                </Select>              </div>
+                    </SelectContent>
+                  </Select>
+                </div>
+              ) : (
+                <span className="text-xs text-muted-foreground">{t('cat.elecraftHint')}</span>
+              )}
             </>
             )}
             {catCfg.backend === 'icom' && (

internal/cat/kenwood.go

@@ -62,6 +62,10 @@ type Kenwood struct {
 	// leave the rig's current mode untouched (safest for a TS-590SG/TS-990S whose
 	// data mode is a USB modifier the operator sets on the rig). See SetMode.
 	dataMode string
+	// elecraft marks a K3/K4 (the "Elecraft" backend). It reuses this Kenwood-dialect
+	// client but, being an Elecraft, always drives digital modes to DATA A (MD6+DT0)
+	// — the sub-mode FT8 audio needs — instead of going through the dataMode option.
+	elecraft bool
 
 	mu   sync.Mutex
 	port serial.Port
@@ -391,6 +395,14 @@ func (k *Kenwood) SetMode(mode string) error {
 	// mode digit fits every rig, so the operator picks: keep the rig's mode, use
 	// MD6 (K3/K4 DATA), or fall through to the default USB from kenwoodModeDigit.
 	if isKenwoodDataMode(mode) {
+		// An Elecraft always uses DATA A for a soundcard digital mode — that's what
+		// the "Elecraft" backend means, so the dataMode option doesn't apply.
+		if k.elecraft {
+			if err := k.write("MD6;"); err != nil {
+				return err
+			}
+			return k.write("DT0;")
+		}
 		switch k.dataMode {
 		case "keep":
 			return nil // leave whatever data mode the operator set on the rig
@@ -424,6 +436,14 @@ func (k *Kenwood) SetDataMode(m string) {
 	k.mu.Unlock()
 }
 
+// SetElecraft marks this client as driving a K3/K4 (the "Elecraft" backend), so
+// digital modes always land in DATA A (MD6+DT0). Set before Start.
+func (k *Kenwood) SetElecraft(v bool) {
+	k.mu.Lock()
+	k.elecraft = v
+	k.mu.Unlock()
+}
+
 // isKenwoodDataMode reports whether a mode name is a soundcard/data mode (FT8,
 // PSK, JT…) rather than a voice/CW/RTTY mode the rig sets natively.
 func isKenwoodDataMode(mode string) bool {