450 MHz Band Pass Filter

Luigi IZ7PDX made this filter. It is a bandpass centered at 450 MHz that Luigi will use as an IF filter.

Luigi IZ7PDX’s centered bandpass filter at 450MHz front panel view.
The filter inside without the notch section activated (“parked” at 580 MHz).

Luigi characterized the filter using ADALM-PLUTO and SATSAGEN.

It’s the setup for the analysis of the filter. Note the attenuator placed on the RX side to improve impedance matching and preserve the RX stage of ADALM-PLUTO from possible damage.
The resulting response curve in a span of 200 MHz. The insertion loss is around 1.3 dB
It’s a scan performed with a 700MHz span.

Luigi has further improved the input and output impedance of the filter by acting on the coupling links and measuring with a vector antenna Analyzer:

It is scanning with a span of 200 MHz after improving the in/out impedance of the filter. The filter is “narrower” in terms of bandwidth than the previous scan before intervening on the coupling links.

Find Luigi IZ7PDX on:
- Youtube channel
- Site


Download SATSAGEN and latest versions from this page:

SATSAGEN Download Page


  • Markers to Max-Hold trace
  • Irradiance compute, in an experimentally way
  • Added NESDR SMArt, NESDR SMArt XTR, nano three, Generic RTL2832/r820t, Generic RTL2832/E4000 devices, and related linearization files
  • Compatibility with LTDZ 35-4400M device
  • Screenshot by pressing the spacebar
  • Added shortcuts: CTRL-M to open Edit SA marker window, CTRL-C to copy the spectrum display to clipboard, CTRL-S to open Settings, and CTRL-T to open the Trace log window
  • HackRF’s manual quadrature in both low and high frequencies ranges
  • Moved all configuration files on the Windows user Documents\Satsagen\Settings folder
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Download SATSAGEN 0.5 and latest versions from this page:

SATSAGEN Download Page


  • Works with:
    • HackRF One
    • RTL-SDR Dongles
    • Simple Spectrum Analyzer series like D6 JTGP-1033, Simple Spectrum Analyzer, and so on.
  • Video trigger, real-time trigger, and fast-cycle feature
  • ADALM-PLUTO custom gain table and Extended linearization table for all devices
  • Transmit from raw format files
  • I/Q balance panel
  • Waterfall
  • RX/TX converter offset
  • Video Filter average option
  • Keyboard or mouse wheel moving markers
  • Status Display
  • The X-Axis CT and SU indicators
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