UHF aerials are not invincible.

They get knocked about - strong gusts, birds, cats, constant exposure to the elements - they can play havoc with your aerial over time.

A damaged antenna can still pick up signals, especially if you're in an area with very good coverage.  However, when conditions change, your antenna will not be able to adapt to those changes as well as a "healthy" antenna would.

When was the last time you checked your UHF aerial?

If your antenna look like the above or is disjointed, rusty, covered in spider webs, then it's time to give it some attention.  Either clean it, replace rusty parts or if the damage is severe, replace it.

You'll find UHF aerials in most electrical retailers (from around $69 - $99); and if you're not confident with replacing the antenna or parts of it, please consult an installer.