This is a reminder that the RF phase of the REFL_A_RF9 and REFLAIR_A_RF9 signals should always be adjusted using the delay line phase shifter. The analog phase shift is applied to the LO signal and therefore effects both analog and digital feedback paths. On the other hand, the phase rotation in the real-time system only changes the digital path. It should always be set to 0°, if the error signal of the REFL servo uses the I output of the demodulator, and to ±90°, if it uses the Q output. One other caveat is that the delay line phase shifter may be in local mode, meaning one has to use the physical toggle switches at the chassis. In local mode the digital settings are getting completely ignored and there is no readback.