Foundations of Amateur Radio
For decades I've been playing with every new piece of technology that comes my way. In amateur radio terms that's reflected in, among other things, playing with different antennas, radios, modes and software.
One of the modes I've played with is slow scan television or SSTV. It's an amateur mode that transmits pictures rather than voice over amateur radio.
A couple of months ago a local amateur, Adrian VK6XAM, set-up an SSTV repeater. The way it works is that you tune to the repeater frequency, listen for a while and when the frequency is clear, transmit an image. The repeater will receive your image and re-transmit it. It's an excellent way to test your gear and software, so I played with it and made it all work for me.
In 2012 I was part of a public event where local schools participated in a competition to have the opportunity to ask an astronaut on board the International Space Station a question as part of the City of Light 50th anniversary of John Glenn's first orbit. The event was under the auspices of a group called Amateur Radio on the International Space Station or ARISS, an organisation that celebrated its 20th anniversary in 2020.
Assisting with the logistics behind the scenes first hand and the amount of equipment used I'd gained a healthy respect for the complexity involved.
The ISS has several radio amateurs on orbit. Among their on board activities are plenty of amateur radio friendly ones. In addition to ARISS, you'll also find repeaters, voice, packet and other interesting signals if you listen out for them.
In previous years I've made abortive attempts at using my station to listen and transmit to space, with varying degrees of success.
On a regular basis the ISS transmits SSTV using amateur radio. Often you'll find a series of images that commemorate an activity. During the final week of 2020 astronauts on the ISS celebrated 20 years of ARISS by transmitting a series of images on a rotating basis as the ISS orbits the earth.
One of my friends made a throwaway comment about listening to the international space station and decoding slow scan television. I'd heard about this event on various social media outlets but put it in the too hard basket.
Based on what I'd seen during my ARISS event, my own trials, and what local amateurs have been playing with in the way of interesting cross polarised antennas, rotators and the like, I'd decided that this was a long term project, unachievable with my current station.
My station consists of a dual-band vertical antenna for 2m and 70cm on my roof at about 2m above ground level. The radio is my trusty Yaesu FT-857d. Connected to a Debian Linux laptop running three bits of software, rigctld, gpredict and qsstv.
With a high level of apprehension I fired up my station, tuned my radio, updated the orbital information and radio frequencies and waited for the first acquisition of signal from the ISS. Imagine my surprise when a picture started appearing on my screen. It's a lot like the days of 300 baud dial up, getting a picture from some remote computer back in 1985.
With that I managed to receive several of the images by just letting it run for the next couple of days.
I'm glad my friend made their comment, because it spurred me into action to try for myself.
I'll be the first to admit that the image quality isn't broadcast ready, or that I made mistakes, or that I should have started listening at the beginning of the week rather than the last few days, but all that is just noise because I can report that it works and I have the pictures to prove it!
I now have most of the image series, number 2 is missing and I only have part of number 1, but there are some beauties among the 35 images I captured. I've published them on my project website at vk6flab.com, for you to have a look at and use as inspiration for your own seemingly impossible task.
This leaves me wondering what else I can hear from overlying spacecraft using this set-up. What have you heard and what equipment were you using to make that happen? Are there any impossible tasks that you've avoided?
I'm Onno VK6FLAB
