RF Band Pass Filters

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Description

  • QRP Labe bandpass filter
  • Used at the front end of a receiver, to attenuate strong out-of-band signals
  • Strong signals that reach the receiver’s first mixer and/or RF pre-amplifier cross-modulate and produce unwanted spurious responses at the receiver output.
  • Double-tuned circuit, among the most common filters found in radio equipment, consists of two tuned circuits, or resonators, that are coupled together, allowing energy in one to be shared with the other
    • Designing a double-tuned circuit for use at HF and below is not difficult,' yet builders commonly encounter practical difficulties in building and adjusting the double-tuned circuit, especially at VHF and above
    • The result may be a circuit that does not meet the filtering goal.

Design Details

Bpf.jpg

Schematic

QRPLabs BP Filter Schematic.PNG

Parts

QRPLabs BP Filter PartsList.PNG

Performance (QRP Labs)

  • Insertion Loss

QRPLabs BP Filter InsertionLoss.PNG

  • 20 MHz

6 20m.jpg

  • 40 MHz

4 40m.jpg

QRP Labs Bandpass Filter

  • 20M - 14 MHz Filter
  • NanoVNA
    • 12-16 MHz

14MHz 12-16MHz Band Pass Filter-2.png

  • Data

14MHz 12-16MHz Band Pass Filter-Data.png

14MHz 12-16MHz Band Pass Filter-Analysis.png