Check the listing for details. CHANNEL PLUS NF-469 LINEAR NOTCH FILTER, CHANNELS 64-70, new in box. Color: Silver, Condition: New. Listed at 28.00 USD. The Channel Plus NF-469 is a Linear brand RF Notch Filter used in Cable Television (CATV) systems to block specific unwanted channels (CATV 64-70 and Off-Air UHF 14-19) while creating space to insert new, modulated TV channels without interference, ensuring a clean signal for systems using modulators like the SVM series. It's a small, in-line device that connects between the signal source and a splitter/amplifier. Key Functions: Filters Out Frequencies: Specifically removes CATV channels 64-70 and UHF channels 14-19. Creates Modulation Space: Opens up those frequencies so you can add your own video channels (e.g., from security cameras or other sources). Prevents Backfeed: Stops your new modulated signals from traveling back up the cable line into the main system.