The contest stations are incorporating new elements that allow them to be more competitive every day. One of these new elements has been the receiving antennas for the low bands (40-80-160m) or adding an Inband station with a far away antenna to avoid the interaction with the RUN station. For example, having several bevarage antennas (different directions as USA and Europe) allows you to hear signals that you would not otherwise be able to hear. Ideally, the same antenna can be used in several stations, which is also highly recommended to include band pass filters (BPF) to reject unwanted signals. As also in a multi-operator environment or SO2R you will have other equipment that are transmitting, it is essential to protect the equipment from an overvoltage that could damage the receivers.
All this is what the FrontEnd Limiter – FEL offers you on the same circuit. The FEL is a PCB where you can connect up to 6 receiving antennas, supports 6 bandpass filters (10 to 160m) and also includes a limiter to prevent damage to your receiver.
Being a Kit, you can logically mount only the components you need or will use, for example if you only use 2 receiving antennas, you only need the relays to switch those antennas and if you only use it at 40-80-160 you only have to mount the bandpass filters of 40, 80 and 160m.