Q: Why do you need to know if your local channel is UHF or VHF?
A: In short, you might need a different antenna to pick up the different frequencies (channel numbers.)
Here are some of the differences between them.
Low band VHF channels 2-6:
- need the largest antenna for good reception
- are more susceptible to electrical interference (like sparkles when someone’s running a vacuum cleaner nearby.)
- take less energy to broadcast (so saves the TV station’s electricity budget)
High band VHF channels 7-13:
- need a mid-sized antenna
- are less susceptible to electrical interference
- take a medium amount of electricity to broadcast
UHF channels 21-51 (were 14-69):
- only needs a small antenna
- are immune to electrical interference
- are the most expensive to broadcast
Here is a video that explains this further.