by 
What is an inversion effect and how does effect tv aerial reception.
Weather related interference occurs mostly in the summer months when periods of high pressure can cause radio waves from distant transmitters to travel further than normal which can result in interference.
On Freeview, this may result in temporary picture break up (pixelation) or you might receive signals from outside of your area.
On Radio, this may result in a weak signal or complete loss of service.
Broadcasters can’t prevent it, and adjusting your aerial will make no difference, and reception will only improve when the weather changes.
High Pressure (Atmospherics)
Weather related interference occurs mostly in the summer months when periods of high pressure can cause radio waves from distant transmitters to travel further than normal which can result in interference.
The diagram below shows the sun heating the ground and the warm air getting trapped between the colder air. When this happens it creates a layer that mirrors the television signal.
It is not possible to exclude completely interference due to the weather, but broadcasters do their planning on the basis that viewers and listeners should be free from this sort of interference for at least 99% of the time, providing they live within the service area of their transmitter and are using a good directional aerial.
Since we cannot control the weather, we have no influence over abnormal propagation through the troposphere and it is only practicable to plan a network where interference is suffered no more than 1% of the time. To improve on this figure, broadcasters would need to increase the number of transmitters drastically and build a much denser network. This is impractical and would be very expensive. Unfortunately, tropospheric-type interference is never spread thinly throughout the year. It tends to happen mostly in the evenings – when television viewing is at a peak and specialist FM programmes are on air. (FM listening peaks in the morning). It often appears at the same time on consecutive days, then disappears for several months. Some years are worse than others, depending on the prevailing weather patterns. Nevertheless, when averaged over several years, the majority of viewers and FM listeners should not be troubled by weather-related interference.
Leave a Reply