I tried two omnidirectional antennas, both well known brands, and was dissatisfied with both.
This article summarizes and compares the main types of antenna.
I'd have to agree with the article. Omnidirectional antennas are used in boats as they are small and as the boat swings at anchor
remains steady, provided there is a clear path to the transmitter.
Regrettably I've found that I usually anchor
in sheltered bays where reflected signals are a pain in the ^#@&.
Almost all TV transmission
outside of cities is UHF, so an antenna for VHF
I'm currently using a small phased array caravan antenna and it works well enough that I don't throw it in the spare parts
If I was to buy another I'd probably try a small Yagi.