Connecting With The ISS


I believe that science provides a methodology to answering questions.  One of these days I’ll get around to writing about the importance of learning to ask good questions.  Until then, let me share with you a bit of an adventure I had with one of my questions.

Can I Talk To The International Space Station?

As a new ham radio operator (KK4TXY) I wanted to find some reasonable goal to put on my list as I explore the possibilities of this new hobby.  For the most part ham radio has some of the most helpful people you’ll ever meet in the community, but because that community isn’t as large as lets say, people who have an iPhone, there’s not a whole of of tutorials on how to specifically use my radio and getting it to do what I want it to do.  At some point in my searching I came across posts about the astronauts aboard the space station using their ham radios and I’m thinking to myself.  Cool!  I want to do that.

As it turns out it’s not as easy as one might think.  There’s a lot involved and the biggest obstacle isn’t the hundreds of miles between them and you (after all that’s just a radio wave with a straight line of sight).  The biggest obstacle is the astronauts’ time.  It’s limited, they’re on a schedule, and unless they’re going to use their free time to talk to random contacts, they’re probably busy doing something else.  That being said, I discovered there are ways of listening to their signals and tracking them across the sky.

forecastangledTo find out when the ISS was going to pass overhead I used the ISS Spotter App for my iPhone.  Although it’s one of many I prefer this app because of its price and the fact that it has an alarm feature that easily tells you when the ISS will be overhead.

With app in hand I discovered that there were several passovers in my area over a few days.  I spent three of those days trying to get a hold of the space station.

Day 1:  W-NW Passover Height 50° time 4 minutes.

For this pass I tried a direct conversation with the ISS using a 50W transmitter (75W is recommended) and an omnidirectional antenna tuned to 145.800 Mhz receive and 144.490 Mhz transmit.  I was indoors and couldn’t see it.  I got nothing on the radio.  I asked why.

As it turns out no one on Expedition 37 has a ham license!  When they have been talking voice it’s been coordinated school events only.  Because they can only do a limited number of those they set up a beacon of sorts that transmits their Automatic Position Reporting System (APRS) data at 145.825 Mhz, but do you think I was quick enough to figure that out in the 4 minutes they flew over?  Nope.

Day 2:  SW-NE Passover Height 84° time 6 minutes.

It doesn’t get much better than this!  A long overhead time at a good angle.  This was going to be awesome.  I opted to use my handheld and just listen for the signal as it passed overhead and watch.  Wouldn’t you know it, any time there’s something good to see in the sky it happens to arrive on the same day as some much needed rain.  Still, I went outside and with a small rubber duck antenna on my iCom ID-51.  I received a total of 18 signals as it passed overhead the strongest at about 70%.  Because I still don’t know how to read the APRS data it transmitted, I can’t do much more than just record the transmission at the moment.

Day 3:  SW-NE Passover Height 43° time 7 minutes.

For this pass we were blessed with a clear day, but the pass was going to occur as the sun was setting.  I was concerned that unless the panels were turned a certain way we wouldn’t be able to see it fly over.  We picked up the radio signals first, but couldn’t find it in the sky.  Then something must have changed in the angle and as it reached its peak the panels started reflecting the light from the setting sun.  I was using my car antenna an OPEK VU-1510 and although the passover had less height, the increased sensitivity of the antenna allowed me to capture a total of 22 signals.  I was out at a tactical shooting course and was able to show the other attendees the ISS.  We watched as it streaked across the sky and disappeared behind the mountains to the east.

Closing Remarks:

This was a fun way to give my curiosity someplace to wander.  It was nice to make steady improvements with each attempt.  There’s still a long way go with regards to making contact with an actual person, but I’m making the steps necessary to be successful for when that opportunity presents iteself.  I’d like to take time for a shout out here to America’s Favorite Scientist for her encouraging words on twitter!  #HappyScience!