Spectran is a program to do real time or deferred spectral analysis / waterfall display, in addition to real time audio filtering (band pass, denoising, band reject and CW peaking) of audio signals, using the PC sound card to digitize the input analog signal, or taking as input a WAV file. Its characteristics are well suited to dig weak signals buried into noise, thanks to a selectable bin size down to 21 millihertz. On the opposite site, it can visualize normal CW signals, resolving individual dots and dashes (with a reasonably fast PC). 

The most notable change in Version 2 of Spectran from the previous versions is in the sound card interfacing portion. The new code has a much reduced latency, and this has the very positive consequence that now there is no more need to "talk" to the sound card mixer, with all the problems of incompatibility that this has generated so far. Interfacing the mixer was needed for the passthrough mode, which, being the latency high, had to be implemented in the sound card hardware. With V2 the passthrough is done in software.
This version of Spectran should have hopefully no more problems with any sound card.



  Latest News :  Special version of Spectran for the UNITEC-I launch  

The UNITEC-1 team will use a modified version of Spectran, which produces a Log file of all the frequency peaks, for an offline analysis.

If you want to download this special version,
you can do it from this link




Current version : Version 2, build 216
The new features of build 213 are:
  • Interoperability with the WSJT program of Joe Taylor K1JT
  • Display of the Moon AZ - EL
  • New "compact" mode, where just a reduced waterfall is shown, so to minimize the screen area used
  • The main window is now resizable
  • Two new palettes added, together with the option of doing an Absolute or Relative color mapping
  • More varieties of WAV files supported
  • You can now record to the WAV file either the incoming audio or the processed audio
  • The passband filter has now a slightly better ultimate rejection


The new features of build 212 are:
  • No more need to interface with the sound card mixer
  • Record and playback to/from WAV files
  • Possibility to select which sound card to use, if more than one is installed
  • HUMID (HUM Instant Destroyer), for 50 or 60 Hz hum (thanks to Paul Nicholson)
  • Band Reject (in addition to the already implemented Band Pass) filter
  • USB / LSB selectable, for a correct display of the frequency scale when offset is used
  • Possibility to delete a previously saved setting which is no more needed
  • Display of the date in addition to time
  • Display "freezable" to give all the CPU time to audio processing (useful for slow PCs)
  • Buffer size adjustable in function of the PC speed, to avoid "choppy" audio with slow PCs
  • Tag field to add a short description (e.g. the call sign of the received station) on the screen
  • Some cosmetic touches

Also, a few bugs have been removed from the code.

Download Spectran V2         

Download the PDF quick-and-dirty guide to Spectran

    These are screen captures in NDB mode. Click one of the images for a full size display.


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