Product Overview
What it is: A hermetically sealed metal RF crystal filter module marked with NS logo, Part No. 726-062-004, and frequency marking 21.88-80 (interpreted as 21.88 MHz, dated 1980).
What it’s used for: Designed for intermediate frequency (IF) filtering in military communication systems, aviation radios, defense electronics, and secure RF signal processing applications. Provides selective signal filtering around 21.88 MHz for stable communication channels.
