• Doug Cook

Connecting with the ISS


KX5DC Logo 72 dpi

I have an amateur radio license – KX5DC.  I have a mobile radio rig in my sport utility. Amateur radio is a great hobby and there are many facets one can explore.  I like to see if I can contact satellites.

The International Space Station has an amateur radio on board.  It is used for school educational contacts during a planned overhead pass.  The astronauts sometimes (though rarely) even spend their off duty hours chatting with people on the ground.

Most of the time the radio while not in use is set to a mode called APRS.  APRS stands for automatic packet reporting system.  This is a digital mode that sends packets of information in brief pulses via radio.  It can be used in many ways – the most popular use is in reporting ones position.

So the ISS (callsign NA1SS or RS0ISS) will digipeat a signal back done it hears as it flies overhead.  I found that the station was due overhead on the way back home from Edmond after eating so I tuned to the frequency of 145.824 MHz and began to listen.  At the predicted time brief  1990’s style modem-like sounds began to be heard.  They sound like electronic “brat” lasting less than a second.  I turned on the beacon on my radio set in APRS mode.  After a few moments my radio heard it’s own beacon coming in.  This was a successful transmission up to the ISS where it rebroadcast the same beacon across it’s horizon covering much of North America.  This is know as a “digipeat.”

My radio was just using 50 watts of power on a mobile antenna that looks like a whip about 3 feet long.  It doesn’t take a multimillion dollar communications system to reach the ISS.

In fact I wrote up an article on how one could do the same thing with a 5 watt handheld portable radio and a homebuilt antenna. Its’ called QRP to the ISS and can be downloaded here http://www.arrl.org/files/file/protected/Group/Members/Technology/tis/info/pdf/COOK.pdf

I made a video also of an encounter with instructions.


Once you learn the skills its so easy, we were even lucky enough to talk with an astronaut using this handheld and an antenna built out of barbed wire.  This event became a published article as well titled “Scouts Snare Spacecraft” http://www.arrl.org/files/file/ARISS/COOK.pdf

We were lucky enough to have a reporter there that captured video of our unique contact made during a Scouting event called Jamboree on the Air.  This contact admittedly is the amateur radio equivalent of a hole-in-one as astronauts are very busy people.


Click to enlarge.

Click to enlarge.


It’s a way to use a $120 billion dollar space station for fun.

Author note: My callsign used to be KD5PDN.  I later changed to KX5DC which I now use.

#amateurradio #APRS #InternationalSpaceStation #ISS #KX5DC

0 views0 comments