To further reduce the RF power at 110MHz in the REFL165 chain, I made a twin-t notch in a pomona box.
It is tuned at 110.66MHz.
The inductor is Coil Craft 5mm tunable (164-09A06SL 100-134nH).
Without the 10Ohm resister (like a usual notch), the dip was ~20dB. With this configuration, the notch of -42dB was realized.
Q >> Please measure the RF spectrum again with the notch.