Global F140 - 4 way amplifier enables use of up to 4 TV links. No mains connection is required as it receives the power from the RF2 of your digibox. The F Series TV booster/splitters are designed to amplify the UHF (TV) or FM (Radio) signals in a poor signal area or to distribute the TV signals around the house. Typically these amplifers are installed in the loft or next to the signal source, e.g. Sky or Freeview receiver