A monoblock (or monobloc) LNB is a single unit comprising two, three or four LNBs and a DiSEqC switch, designed to receive signals from two, three or four satellites spaced close together and to feed the selected signal to the receiver. The feedhorns of the two LNBs are at a fixed distance apart for reception of satellites of a particular orbital separation (often 6°, but also 4°). Although the same functionality can be achieved with separate LNBs and a switch, a monoblock LNB, constructed in one unit, is more convenient to install and enables the two feedhorns to be closer together than individually cased LNBs (typically 60mm diameter). The distance between the feedhorns depends on the orbital separation of the satellites to be received, the diameter and focal length of the dish used, and the position of the reception site relative to the satellites. So monoblock LNBs are usually a compromise solution designed to operate with standard dishes in a particular region. For example, in parts of Europe, monoblocks designed to receive the Hot Bird and Astra 19.2°E satellites are popular because they enable reception of both satellites on a single dish without requiring an expensive, slow and noisy motorised dish. A similar advantage is provided by the duo LNB for simultaneous reception of signals from both the Astra 23.5°E and Astra 19.2°E positions.