To build a cable TV headend, you need several components: 1) Video modulators to modulate different video sources into RF signals for transmission over coaxial cable. Sources may include satellite feeds, terrestrial TV channels, internet, and local programming. 2) A combiner to combine the multiple RF signals into a single physical RF signal for distribution. 3) Demodulators and receivers for incoming video sources like satellite dishes and antenna. 4) Optional components include a CMTS for internet, AV and RF monitoring systems, and a logo generator. Together these components make up the basic analog headend to distribute multiple video channels.