Monday, February 2, 2015

International Space Station SSTV Transmission

      It was amusing moment for the Ham radio operators to acquire Slow Scan Television Signal (SSTV) transmission experiment from International Space Station -ISS by active Russian Crew on behalf of 80th anniversary of the first cosmonaut Yuri Gagarin on December 20th, 2014 as well as January 31’st and February 1st  ,2015.

Fig:1 ISS SSTV Signal Transmitted under Call Sign RS0ISS on DECEMBER 20th, 2014



      For receiving and decoding this signal what you need is a VHF receiver or transceiver which can receive downlink signal 145.800 MHz frequency and a PC with SSTV decoding software which supports PD180 Mode (RX Only) like MMSSTV, RX-SSTV or MULTIPSK and a Satellite tracking software or online tracking web support google it there are plenty I used a software called gpredict.

Fig:2 ISS SSTV Signal Transmitted under Call Sign RS0ISS on FEBRUARY 1st, 2015
Fig:3 ISS SSTV Signal Transmitted under Call Sign RS0ISS on FEBRUARY 22nd, 2015
Fig:4 ISS SSTV Signal Transmitted under Call Sign RS0ISS on FEBRUARY 23rd, 2015
Fig:5 ISS SSTV Signal Transmitted under Call Sign RS0ISS on FEBRUARY 24th, 2015
Fig:6 ISS SSTV Signal Transmitted under Call Sign RS0ISS on FEBRUARY 24th, 2015
SSTV 19th July 2015 @5:25 UTC Transmission from ISS Russian Service Module to commemorate the 40th Anniversary of the Apollo-Soyuz Mission.

      Monitor carefully the passing time of the satellite above your horizon. You will get two event times like AOS (Acquisition of Signal- Time when you can hear satellite or it is in your range) and LOS (Loss of Signal/Satellite- Time when satellite is out of your range) note down this timings.

      There are two methods of decoding one is live decoding and other is standby decoding. Live decoding stands for decoding the signal at the same time its received from the ISS. The standby decoding involves recording of the signal using voice recorder then decode it.  This topic Covers both methods.

  • Live Decoding

      I used this method to decode the SSTV signal as i had an homebrewed Rig-PC interface. Connect the audio output jack of receiver to line input of the PC and run the decoding software just before the satellite footprint appears above your location AOS time event. The decoder software will auto detect the received signal from ISS and will decode it to generate the Image.

  • Standby Decoding

      This method involves recording of the received signal, adopt this method if you don't have a Rig-PC interface. First record the SSTV signal using voice recorder open the decoder software MMSSTV then play the recorded file.

Other Images Received

      Here are few images received on February 1st, 2015 at different instance. The images are not complete due to LOS within the signal transmission interval as well as the 3 minutes off time between the transmission and also because of poor elevation.


Fig: 1a Image received on 5:58 IST February 1st 2015

Fig: 1b Image received on 7:19 IST February 1st 2015

Fig: 1c Image received on 17:33 IST February 1st 2015

Fig: 2d Image received on 20:10 IST February 22nd 2015


That’s it Congrats, You have just learned to decode an SSTV signal.

Important Software Links



2 comments:

  1. Great write up Sooraj..

    DE VU3KNB

    ReplyDelete
  2. commentable work and guidance to all interested in ISS

    ReplyDelete