Antenna amplifiers are broadband RF amplifiers that cover several frequency ranges or even several frequency bands. This means that antenna amplifiers may well amplify the VHFrange, the VHF range and UHF range and even the signal coming from the LNB converter together. There are narrowband versions that amplify a specific frequency band or range.
Antenna amplifiers are installed near the antenna and amplify the RF signals coming from the antenna, which are then transmitted via the antenna cable to the set-top box, receiver or tuner. Because the antenna amplifiers are located near the antenna, the signal's reception level is already boosted before it is applied to the antenna cable. Since it is attenuated on this and can also absorb HF interference.
The gain of antenna amplifiers is fixed or adjustable in steps. It can range from 10 dB to over 30 dB. It can be supplied via the mains voltage, but also via the antenna cable. Corresponding antenna amplifiers are called inline antenna amplifiers. On the input side, antenna amplifiers can have inputs for medium wave, FM broadcasting, the VHF range and the UHF range, and for LNB converters.
On the output side, the devices can have one or more outputs for single- user antenna systems but also for multi-user or community antenna systems. The input impedance of the antenna amplifiers is matched to the cable impedance of the antenna cable, and the same applies to the output impedance. Antenna amplifiers should have low noise, high sensitivity and linearity. The latter is particularly important for avoiding intermodulation.