For best reception results you need a good quality rooftop UHF aerial directed at your nearest transmission tower. 

If your UHF aerial is misaligned or poorly positioned, you will see:

• Intermittent reception problems across some or all channels;
• Pixelation (blocks or jumbled picture) or loss of channels;
• Loss of an entire multiplex of channels (or pixelation across the multiplex).

You may often get loss of channels or reception issues when it rains or when there is a major high pressure system over the country producing a string of very sunny days.  This is because the misalignment of your antenna is very sensitive to changes in signal levels, which can change with the weather.

FACT When the antenna is correctly installed and aligned, you should not experience any reception issues.  So if you do get ongoing "off and on" reception problems, look to your antenna and it's best to check with an installer.

You can check a few things to see if your antenna could be positioned or aligned better

• Look at your neighbours' antenna - is yours pointed in a different direction compared to theirs?
• Whether your antenna is pointed at your nearest transmission site (see coverage map for your area on this page) - if it's significantly off-course, it's misaligned.
• Whether there're trees, tall buildings, power pylons and other structure that could obscure the signal path from the transmission site to your antenna - if yes, you may need to reposition your antenna to avoid those (or in the case of trees, trim them).