t. The installer must balance this gain/loss to allow a sufficiently strong signal to arrive at the receiver given the length and quality of the antenna cable. To boost the very weak signal from space, the GNSS antenna contains a pre-amplifier in its base. This pre-amplifier is powered by a voltage (typically less than 5-V DC) that is applied to the coaxial antenna cable by the GNSS receiver. Again, this gain from the amplification is ad- ded to the calculation when determining the signal strength that reaches the antenna port on the receiver. Many times, when an antenna is installed for a GNSS application, there are many other receiv- ers in the same location that can also share the antenna. For this reason, many installations in- corporate a splitter, which allows the signal to be shared between many receivers. This splitter must be capable of moderating all the DC voltages coming from the receivers without over-sup- plying power to the pre-amplifier. The splitting of signals into multiple paths also reduces the signal strength, adding another factor to the gain/loss calculation. The antenna will detect a wide band of unwanted radio signals around the narrow spectrum car- rying the desired GNSS signal. For this reason, antenna installations have filters that only allow a very narrow range of frequencies to pass, those that the receiver wishes to detect. The installer must make sure that the antenna is sensitive to the band that the GNSS receiver can process, and that the correct narrow-band filters are used SO that the sought-after signals pass through to the receiver. It is pointless to have a multiband and multi-constellation receiver when either the antenna does not detect the transmission or the filters block most of the signals. Local (fire) authorities may have regulations about what sort of cable can be run through the ducting of a building and specifically the rating on the outside insulation layer of the cable. For example, there is a cable type called low smoke and fume (LSF) that may need to be used 