Ever wonder why the stereo pilot is 19 kHz, not 20 kHz, and how that choice ties to the 38 kHz subcarrier, the 15 kHz program low‑pass, and keeping the composite inside the FCC/NAB multiplex mask without compromising SNR or deviation? If anyone has an original GE/Zenith or FCC memo on the 19/38 scheme, I’d like to compare it to a 1963 alignment sheet I use in the shop…