Click the beacon on the spectrum; the controller tracks it and continuously
trims the transverter LO so the whole downlink stays put as the LNB drifts.
- BeaconLock.pas: TBeaconTracker scaffold (narrowband NCO/FLL) — kept but no
longer in the control path (FLL diverged on the suppressed-carrier BPSK
beacon + Pluto DC offset). Measurement now uses the proven display-FFT path.
- RadioController: FBeaconLockHz folded into XvtrTranslate (on top of LOError).
MeasureBeaconFFT finds the beacon by POWER-WEIGHTED CENTROID of the lobe
(BPSK has a suppressed carrier → broad symmetric ~2.4 kHz lobe, not a line;
a peak-finder jitters, the centroid sits on the carrier). Track position in
ABSOLUTE display Hz (FBeaconTrackHz) so scrolling the waterfall/centre never
moves the search window off the beacon. Closed loop: e = tracked - ref,
d(e)/d(LockHz) = -1 -> LockHz += gain*e; settle cooldown after each correction
(display-FFT lags the LO retune -> avoids overshoot); deadband 75 Hz +
centroid/prominence smoothing + lock hysteresis for a steady lock.
Correction applied only after the user clicks (manual seed), so a crowded
band can't pull a neighbour to the reference.
- WDSPEngine: SetBeaconTracker + RX-IQ tap (tracker idle now, ~1 check/sample).
- SpectrumView + GL: beacon markers — green = reference (10489.750), orange =
tracked centroid.
- MainForm: BEACON button (RX block, XVTR-only). Flow: BEACON -> "CLICK BCN"
-> click beacon -> "L<corr> /<prom>". ServiceBeaconLock driven by MeterTimer.
Reference defaults to the middle BPSK beacon 10489.750. Tested on-air against
Es'hail-2: locks and holds, survives waterfall drag.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
