Television signal cannot be received generally beyond a particular distance due to

Television signals, which typically operate in the VHF and UHF frequency ranges, propagate primarily via line-of-sight transmission [t1]. Unlike lower-frequency radio waves that can reflect off the ionosphere (skywave propagation) or follow the ground (groundwave propagation), TV signals travel in straight lines and are not reflected back to Earth by the ionosphere [c1, t1]. Consequently, the curvature of the Earth presents a physical horizon that limits the range of these transmissions [t3]. Beyond this radio horizon, the signal cannot be received because the Earth's surface obstructs the direct path between the transmitter and the receiver [t1, t3]. While factors like transmitter power and antenna height influence the specific range, the fundamental geographic limitation for terrestrial broadcasting is the Earth's curvature [t1, t8].

Sources

1. [1] https://imdpune.gov.in/training/communication/LN_11_60_Radio%20Wave%20Propagation%20Theory.pdf
2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Why Are Microwaves And Some Radio Waves Not Reflected By The Ionosphere? > p. 278