Built-in amplifier to boost signal gain up to 42 dB. Indoor aerial for superb reception of DVB-T/Freeview. Receives both analogue and digital signals. For best performance we recommend to use this aerial within a range of 9 mi from your nearest transmitter. This aerial has a unique 3G/4G block-filter to block all 3G and 4G mobile phone signals, to ensure the best possible reception, now and in the future.