Afreet Software, Inc.
     Software created by Alex Shovkoplyas, VE3NEA


RTTY Skimmer Server


DX Atlas

CW Skimmer

CW Skimmer Server

Pileup Runner

DX Bulletin Reader

Voice Shaper


Band Master


Morse Runner



Morse Midi


Tech stuff



QRQ Profiler


SSTV Tools


SSTV Tools

A set of troubleshooting and research tools for the SSTV enthusiasts.
For Windows 95/98/ME/NT4/2000/XP/7


All downloads are on the Downloads page.

SSTV Signal Generator

What it is
This program generates SSTV audio signals from a bitmap and saves them in a WAV or MMV file. Multiple SSTV formats and sampling rates are supported. The software can generate either a clean signal suitable for transmission, or a signal contaminated with noise, suffering from QSB, etc. - much like in Morse Runner, but with all effects carefully calibrated and measured in dB, Hz, and ms.

What it is good for
  • Create pre-canned SSTV messages, such as "CQ" or "73 DE", and transmit them without any SSTV software, just by playing the audio back in a media player.
  • Test your SSTV receiving software and see how tolerant it is to the noise, soundcard calibraion errors, receiver frequency offset, etc. Compare different receiving programs quantitatively.
How to use it
  • Specify the bitmap and output file name, set other parameters, and click on the Generate button.
  • Use only the 320x256, 24-bit BMP files.
  • Tick the Distort The Signal check box to enable the distortion controls.
  • If you enable QSB, add some noise as well. The signal is supposed to go below the noise during the QSB nulls.
  • To model selective fading, use the Multipath option, set a short delay of 1-2 ms and an amplitude ratio of 0 dB.
  • To model echo, use the Multipath option as well, but set a longer delay and a lower amplitude.

SstvGen.png, 42kB

SSTV Signal Generator

SSTV Signal Viewer

What it is
This program demodulates FM signals from a WAV or MMV file and plots the frequency and magnitude vs. time. It is an extension of the original idea by OK2MNM, implemented with GUI and using a better FM demodulator based on Hilbert transform.

What it is good for
You can use it to view both the files generated by your SSTV program and the ones recorded off the air. Find out what exactly your signal consists of, how accurately it is generated, see how the FSK ID is encoded, discover the parameters of an unknown format, etc.

Explore other FM-based modes, such as RTTY.

How to use it
  • Click on Open File and select a file to view.
  • Tick the Mag check box to display the signal magnitude plot.
  • Use the sliders to change the vertical and horizontal scale.
  • Scroll the plot by dragging it with a mouse or using the scrollbar.
  • Use the mouse wheel to zoom in and out.
  • View the signal paramteres on the status bar: time, frequency, luminance corresponding to that frequency, and signal magnitude.
  • Right-mouse-click and drag to measure the time interval between the points on the plot.

SstvView.png, 47kB

SSTV Signal Viewer showing the last scanline and the beginning of the FSK ID of an SSTV signal

SSTV Image Denoiser

What it is

This program removes noise from the pictures. The denoising algorithm is specifically optimized for the SSTV images received off the air. Unlike other noise filters used in SSTV software, this one does nor blur the image, and preserves as much fine detail as possible.

What it is good for

Clean up your archive of SSTV pictures, prepare received images for publishing on the web.

How to use it
  • Click on the Load Image button, and select the image that will be denoised.
  • Select the filter order and smoothness parameter. The default order of 3 and smoothness of 0.4 are a good start.
  • Click on the Denoise Image button.
  • Play with the filter settings and find the parameters that work best for the given image.
  • Click on the Save Image button to save the denoised image.
For best results, configure your SSTV software to save received pictures as BMP. Though the Denoiser can load and save BMP, PNG, JPG and GIF images, it works best on the uncompressed BMP files. Images compressed with a lossy algorithm, such as JPG, may look great, but they do not contain all information required for denoising.

Examples of denoised images

Before denoising

After denoising

Before denoising

After denoising

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