Universal Lowpass filters for HF Amateur Transceiver (LPF) This Lowpass filters for harmonic filtering at the output of the amplifier can be used with amateur transceivers There are six two-element low pass filters (LPF) in this design. The switching of bands regulates by Relays. Relay P1 (12V) at output of lowpass filters connects to the Power Amplifier or Bandpass filters of transceiver. It identify the RX/TX modes. The bands 7MHz and 10 MHz, 18 MHz and 21, 24 and 28 MHz unified and have a common low pass filters, switching relays of these bands is carried through the decoder diodes. PCB dimensions 90х62 mm.