What you are hearing and seeing are meteor pings (echoes). Terrestrial VHF signals can be reflected by the ionized trails left behind when tiny meteors burn up in upper atmosphere. More
If you see and hear sometimes a strong continuous signal that runs for more than a minute or so, that is unlikely to be a meteor echo. VHF radio waves are sometimes affected by an unusual form of ionosphere propagation called "Sporadic E". During this event which can last hours or even days, the radio signal originating from the distant station is reflected by the ionosphere and meteor echoes are impossible to be detected. Sporadic E is specific to summer season in Northern Hemisphere.