The Channel Plus NF-470 Notch Filter couples the incoming signal source coax cable to the input on a splitter or bi-directional DA-series amplifier. Once installed, the NF-470 filters out channels to make room for modulated channels. In addition, the NF-470 blocks the modulated signals from being broadcast back into the coax. The NF-470 is a perfect solution for modulation in the ever-increasing bandwidth taken up by CATV. The NF-470 Notch Filter blocks incoming CATV channels 70 - 74 and off-air UHF TV channels 19 - 23, allowing 5400, 5500 and SVM series modulators to insert TV channels without interference.