Method activateRADE

src/gui/MainWindow_DigitalModes.cpp:201–514

#ifdef HAVE_RADE
void MainWindow::activateRADE(int sliceId)
{
    // Guard against duplicate activation (VfoWidget + RxApplet both selecting RADE)
    if (m_radeSliceId == sliceId && m_radeEngine && m_radeEngine->isActive())
        return;

    // If RADE is already active on a different slice, deactivate it first
    if (m_radeSliceId >= 0 && m_radeSliceId != sliceId)
        deactivateRADE();

    auto* s = m_radioModel.slice(sliceId);
    if (!s) return;

    // Capture TX slice owner before potentially moving the badge, so the
    // failure path can restore it.  -1 means no TX slice existed.
    int prevTxSliceId = sliceId;
    if (!s->isTxSlice()) {
        prevTxSliceId = -1;
        for (auto* sl : m_radioModel.slices()) {
            if (sl && sl->isTxSlice()) { prevTxSliceId = sl->sliceId(); break; }
        }
    }

    // RADE needs to be the TX slice so it can transmit modem audio.
    // Move TX badge to the RADE slice automatically.
    if (!s->isTxSlice())
        s->setTxSlice(true);

    // Set radio mode to DIGU/DIGL (passthrough for OFDM modem).
    // Use band convention from BandDefs to pick sideband — 60m is USB
    // despite being below 10 MHz (#875).
    double freqMhz = s->frequency();
    QString mode = "DIGU";
    for (const auto& band : AetherSDR::kBands) {
        if (freqMhz >= band.lowMhz && freqMhz <= band.highMhz) {
            mode = (QString(band.defaultMode) == "LSB") ? "DIGL" : "DIGU";
            break;
        }
    }
    const QString prevMode       = s->mode();
    const int     prevFilterLow  = s->filterLow();
    const int     prevFilterHigh = s->filterHigh();
    s->setMode(mode);
    if (mode == "DIGL")
        s->setFilterWidth(-2250, -750);
    else
        s->setFilterWidth(750, 2250);

    // Remember which slice and its previous mute state
    m_radeSliceId = sliceId;
    m_radePrevMute = s->audioMute();
    s->setAudioMute(true);

    // Auto-deactivate if the slice mode is changed externally (TCI, profile
    // load, remote SmartSDR client) — those paths bypass the VfoWidget and
    // RxApplet combos and would otherwise leave audio_mute=1 stranded.
    connect(s, &SliceModel::modeChanged,
            this, &MainWindow::onRadeSliceModeChanged,