SSDV is Slow Scan Digital Video, where still images are encoded in SSDV format, including error detection and correction codes. The images are broken into small number of chunks before being transmitted via FM usually using baud rate, eg. 1000 baud.

We use SSDV to get near real time images back from High Altitude Balloons.

To receive images from SSDV payload (where available):

Required hardware:

  •  FM receiver for the appropriate frequency (generally we use 434.650MHz)

  • Mac or Windows computer with a soundcard input.

  •  Internet access for uploading images and telemetry to internet servers.

Download and install dl-fldigi from this page:

The setup program will create two shortcuts, the one you will need is called “Dl-Fldigi 3.21.50 HAB mode”

Run dl-fldigi. On first startup you will be asked to enter a few details, including call sign and receiving/antenna being used. Enter these details as appropriate.

Go to “Configure” and select “Sound Card”


Select your sound card in “Capture” and enable “Port Audio”


Select “Modem” and “ BPSK1000” setting.

Please note that the BPSK1000 mode is only available on the MARTG version of Fldigi please send an  email to if you would like a copy. The custom version will allow you to decode BPSK1000 required for receiving images.

Save the settings and close the Configure window.

Connect the audio output from your FM receiver to the soundcard input.

Ensure “DL Client” Online status is selected to enable internet uploading. Turn this off
for testing.



If all is well, you should see the FM signal on the waterfall display. Ensure the red receive bandwidth markers are aligned with the signals.

Select View/SSDV RX to show the received SSDV images

It should look like this:


Congratulations, you are now setup for receiving and uploading images to SSDV servers.

All uploaded images can be viewed at

Tracking of the payload can be seen here