What Is : D. Kaminski " IF_Average " ??

[Alex P]

What is the ( D. Kaminski ) “ IF_average “  ?

 

IF_ave is a Radio Astronomy Plug-in for the

AirSpy  SDR# Studio SDR Control and Acquisition Software package.

 

IF_ave allows spectral averages of several minutes ( hundreds of thousands of averages)

             to be acquired, auto numbered & saved in a 2-column ( freq/ampl) *.txt format.

 

IF_ave allows a pre-defined Background Correction File to be obtained to ( in real time )

correct the Spectrum Display Plot . It removes the large M-Curve filter shape commonly seen in other software from both the Display and Saved Data Files.

 

This:  the IF_avg Real Time Spectral Display

 (  Background Correction Plot )        ( Corrected H Line Spectra )

 

VS

This :  In other software,  the M Curve dominates the displayed spectrum

    such that H Line Spectral Data is difficult to see

 

Background Correction Technique

 

The M-Curve is a Gain Variation over the spectrum frequency range from the filter shape.

Thus the  Data Frames are Divided By the Background Correction File

        

To Acquire this Correction Frame,

 

a )  Point at an empty part of the sky (far away from the milky way and H-line sources)

 

b ) Point the antenna towards the Ground. But if there is any H line overhead, it will bleed into the background. Sometimes pointing the dish ground-ward works, but it may also pick up neighborhood RFI

 

c ) If the system uses a simply removable LNA such as the SAWbird, disconnect it from the antenna and attach a 50 Ohm Load to the LNA Input for the process.

 

d ) For systems where that is not easily done ( Discovery Feed &  others ) ,  use a 1" stack of Dense Conductive Foam over the Feed.  ( Al Foil changes the SWR, so I never used it, but it apparently also Works fine for this purpose)

 

 

Advantage of the Background Correction ?

 

1 )  It allows you to see even the faint H line ~ RA12:00 regions .

 

2 )  See in Real Time : Large & Small amounts of RFI and turn off the monitor or appliance            before it disrupts hours of data collection !

 

3 ) AND when acquiring Bright H Line regions, observe real-time minute-by-minute  amplitude changes !   ( yes really )

 

 THIS allows you to monitor and time correlate your data acquisition plots

           to accurate spectrums as this from CCERA

 

   ==================================================

 Download AirSpy SDR# Studio with Kaminski IF_avg pre-installed

==================================================

Configuration / Operation / Plotting  / HLine3D Processing and Rinearn Graphics

 

 

==========================================================

Comment from the Author :

Next year, we plan to restart the project from scratch. The goal is to use a new template based on SDR# and build it on the latest version of .NET.  Once that is done, we can add more features and options           ==========================================================

 Best Regards,

   Alex Pettit

[b alex pettit jr]

==================================================

 

Download AirSpy SDR# Studio with Kaminski IF_avg pre-installed

 HERE

IF_Ave  Ver 2.7 &  2.8 PlugIn for SDR# Studio

 Full Installation of SDR#  & IF_Ave 2.7

https://www.dropbox.com/scl/fi/2f67lyu6qgt2cp98rg9kp/SDR-2.ZIP?rlkey=y82yv6jzjyu7e92sap3x8ewm7&st=tcil7w3s&dl=0

The latest Rev of IF_Ave  allows

  Saving and Recalling  named Background Correction Files replace the above with this newer * DLL

 

IF_Ave Version 2.8

https://www.dropbox.com/scl/fi/aitn8xtookwwxm6mvybkp/SDRSharp.Average.dll?rlkey=667f4a83958krn77ie2862jxf&dl=0

==================================================

Configuration / Operation / Plotting  / HLine3D Processing and Rinearn Graphics

  HERE

https://github.com/AP-HLine-3D/HLine3D

 

============================================================

[flavio camacho]

Thank you much. 

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[Stephen Arbogast]

Yes, I understand spectral averaging, low pass filtering and subtracting out the background level .  I don't understand the IF part in IF_Averaging.  What comes to mind is Intermediate Frequency but there is no intermediate frequency in the SDR's we use.  So  I am guessing it means If some condition is met then perform averaging per parameters.

????

[b alex pettit jr]

I don't understand the Name either.. ..

Other than time averaging, There is No Filtering .

The background correction curve is a Gain Variation & it is corrected by Division not subtraction.