SONICPHOTO – Pictures in the Waterfall


Picture in the Waterfall
3cm SSB Hellschreiber, 122km to SUWS’s Farnham webSDR


Not very useful for communications but 10 out of 10 for play value. SonicPhoto by Skytopia is a free demo download that will convert a JPEG image on your PC into a sound. With suitable settings for radio transmission, the sound will ‘draw’ the picture directly in a waterfall display attached to a receiver.

The program was not designed for radio use but to create unusual sounds for musicians. Essentially it runs a scanned inverse FFT left to right across a JPEG image, the output of which is a sound – which just happens to be exactly what my PP/MT Hell generators do with text, in other words this is pure frequency domain Hellschreiber but for pictures using 100’s of simultaneous brightness modulated tones of the scanned photo.

It works best with simple white on black line drawings but is fully capable of B&W photo’s if the received S/N is high.

The quickest way to understand how it works is to set it up and play with the settings.


1. Down Load and install SonicPhoto (Demo version) HERE
2. Down Load and install Spectran (if you don’t have it already) HERE
3. Run both programs either on the same PC or better on two different PC’s
4. Couple the Audio OUT from SonicPhoto to the Audio IN on Spectran
many ways – jack lead from Out to In, Virtual audio cable software or
simply as I initially did, play SonicPhoto’s audio through the speaker
and select a mic input for Spectran.

Use windows ‘Snipping tool’ to turn any line drawing or text into a jpeg photo, load the .jpg image into SonicPhoto and press ‘play’ Spectran will display the spectrum of the resulting strange sounds.

To get a sensible picture on Spectran, I suggest starting with the following settings in SonicPhoto (listed in order of importance) :-

1. TONE = 0.00, LINEAR
4. LOWEST Freq = 300 (normal speech band-pass for a radio)
5. HIGHEST Freq = 3000 (sets the total bandwidth of the sound)
6. SOUND TIME = 7sec (Free Demo version is limited to 8 seconds)
7. QUALITY = 399 (Wow ! 399 tone Hellschreiber)

SonicPhoto setup for radio

SonicPhoto settings for Radio Transmission


as received at the SUWS webSDR Farnham on 3cm
as received at the SUWS webSDR Farnham on 3cm


A FUZZY picture mode, plenty of ‘knobs’ to play with to get a good picture.


Experimentation,  the true spirit of Amateur Radio.