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Helical antennas are suitable for high frequency transmission and reception in the UHF band and higher. The antennas are likely mounted on a movable platform to track satellites TX RX

Circular polarised satellite comms. Radio waves, natural or manmade, travelling around the Earth tend to have vertical polarisation - the others get absorbed by conductive surface terrain. If you're listening for other Earth-based stations, you want that, even though it comes with a lot of noise. So vertical antennas. If you're listening for satellites, though, you don't need to care about conductive surface terrain, and you can skip dealing with all the noise by using circular polarisation, which travels just fine through space. Winning at engineering is all about the cheat codes :p