digital is prone to interference from the same electric (spikes) that cause computers to crash,running through electricity mains,causing a click and volume loss or picture (freeze)u could try buying a surge protected plug adapter that may help,also central heating thermostats when faulty can have a effect on (receiver) equipment.IE:TV or radio.intercom any thing that uses a frequency.also try not using the Ariel signal booster and see if the problem subsides.boosters are mainly for analogue reception to enhance UHF or vhf signals, digital is transmitted in blocks of information and decoded by your set top box ,in my experience boosters make the situation worse. if the Ariel is misaligned or weather beat the booster enhances the bad reception to a louder brighter bad reception in analogue,and a complete overload on your set top box circuitry.