Abstract: The invention which is the subject of this application relates to particularly, although not necessarily exclusively, a form of apparatus known as VSAT. VSAT or Very Small Aperture Terminal is a sophisticated communications technology that allows for the use of small fixed satellite antennas in premises to provide highly reliable communication between a central hub such as a data broadcaster, and almost any number—tens or thousands—of geographically dispersed sites or premises. The invention allows the provision of a Ground Outdoor Unit ODU for the apparatus in an integrated format without the need for separate components to be provided by using progressive amplification and filtering of the transmit or received signal and allowing the required isolation of the receive and transmit signals even at the VSAT apparatus operating conditions. The invention is also of use in any form of signal receive and transmit apparatus.