Final answer:
SETI programs like the Allen Telescope and the Green Bank Telescope have highly powerful transmitters and sensitive receivers, enabling the search for extraterrestrial signals across broad frequencies to increase the chance of detection.
Step-by-step explanation:
When it comes to the power and sensitivity of radio systems, particularly in the search for extraterrestrial intelligence (SETI), the Allen Telescope Array in Northern California, and the Green Bank Telescope in West Virginia are notable. These telescopes, along with others like the Arecibo (no longer operational) and FAST dishes, are designed to detect radio signals from space with great sensitivity.
The channel's frequency width, signal strength, and continuity are key factors in the SETI endeavor. Modern electronics and software enable simultaneous searches across millions of frequencies, allowing a broad frequency range to be covered. This reduces the 'cosmic haystack' problem of finding the correct frequency. Setbacks remain, however, such as the signal strength being too weak for detection by our telescopes, the vast number of potential channels, and the need to decipher the coding within the signal.