International Space Station Packet Downlink

Posted on February 8, 2016 Updated on February 9, 2016

I have been spending some time this week exploring the excellent Ham Radio Delux software with my Yaesu FT 857D. Having set up the DM-780 digital software as part of HRD to send and receive PSK31 and other digital modes I decided to have a look at the satelite software.
I am really impressed with this piece of kit! It can track and display the Amateur Radio satelites along with many others including the ISS. By putting in your locator or co-ordinates you can track the ISS and other satelites. The World map tracks and displays the ISS and even gives you an oral warning when the ISS is about to come into view. There is also a button which will link to Google Earth and show real time images of the ground and sea as the ISS tracks around the Earth.

Last night I listened to the packet data as it passed on 145.825Mhz FM with my FT 857D for the very first time. Tonight I wanted to try again, but this time try to decode the packets using AFSK1200 software. This piece of software is very simple and only two buttons (start / save) to make it work.

In my first attempt I managed to hear some data and decode some with AFSK1200, on this pass the ISS was very high. On the second pass the ISS was much lower, but I was able to receive a stronger signal with my horizontally polarised 5 ele beam. This produced a whole lot of packet data and stations through the ISS. I notice that while the ISS is near to England there is not much packet activity, but as it moves over Europe it becomes stronger and we receive packets from the continental stations. Also, it seems to work best with a low pass.

The World Map in HRD showing the tracked ISS giving information. On the left is information about the passes of the ISS showing times, tracking and azimuth of the ISS from my location…cool!

Packets received from the ISS displayed in AFSK1200 during the second pass tonight.