A dream finally realized: Working the ISS!

Wow! Has it really been 2.5 YEARS since I’ve posted here? I suppose so, as I haven’t done any amateur radio in at least that long. 

Anyway, the Covid-19 pandemic forced me to shelter at home for a couple months, and during that time, I felt like it would be a good idea to exercise the radios. I pulled out the FT-817 and enjoyed listening to QSOs on all bands, listened in on local nets on my handheld, and just cleaned up the shack a bit.

My shack computer, an iMac from 2011, gets used for video editing and recording audio — however, I dual boot it into Windows 7 for ham radio ops. I hadn’t done that in a while, but I was pleasantly surprised to see DX Lab and all my logging programs were still intact. The K3 and P3 still fired right up. 

Satisfied that everything was still in working order. I turned my attention back to other matters — making music, work projects, producing podcasts (more on that in a future post perhaps), and other trivial things. 

A couple weeks back on Reddit I saw a post on the amateur radio subreddit, from a gentleman who received a QSL card from the ISS, after working the station’s digipeater with APRS. I got into ham radio back in late 2011 specifically for the purpose of communicating with the ISS. Short of receiving some voice transmissions, and slow-scan TV, I’d never successfully talked with anyone aboard the station.

Owing to my own ignorance, I had no idea you could get a QSL card from the station by using the packet digipeater — in fact, I didn’t even understand what the digipeater was. Talk about not doing my homework — this is the BEST way to use the amateur gear aboard the ISS and probably the only chance of success, unless we get another astronaut onboard that enjoys talking to hams.

So, with some interest in radio being slowly rekindled, and feeling some pride for humanity after the first manned SpaceX launch in late May, I decided it was time to once again try working the ISS — this time, using packet, a mode I knew next to nothing about.

I don’t own a packet modem, but I always enjoyed the sound card digital modes, so surely there is a way to use something like a Signalink to operate packet. There sure is: Enter the UISS program. That’s all you need!

This past weekend I assembled my dual-band Yagi LEO satellite antenna and listened for the ISS on a Saturday pass using my VX-7. The uplink and downlink is VHF, 145.825. Yep, the digipeater was active. I could hear it easily, and recorded the transmissions on my phone. I later decoded them with UISS and confirmed I was indeed hearing the station, operating under the Russian callsign, RS0ISS.

Sunday, I configured UISS, re-jumpered my Signalink for the FT-817 (Yep, let’s do this QRP), and got up before dawn on Monday for an early morning ISS pass. I was not successful. I heard perhaps three transmissions from the station over the Yagi. Only one was decoded. I transmitted my APRS information repeatedly, but I wasn’t picked up, according to the “stations heard” page run by ARISS. Back to the drawing board.

Later that night, I pulled out my FT-8800 mobile rig and configured it for packet using 50W of power. I decided I would use a vertical mag-mount antenna for my next attempt, which would be on Wednesday around 1 p.m. It was a low ISS pass, but in the northeast sky. From my backyard, I have a clear view in this direction.

I also realized my sound card settings needed some tweaking. While monitoring my signal during testing, it sounded like the full packet wasn’t getting transmitted. I adjusted the transmission delay in software to make the radio to wait a half second between keying up and sending the packet data.

The Wednesday pass couldn’t have gone better. Right as the station came over the horizon I could hear packets. The transmissions were scratchy at first, then became very clear. UISS was decoding nearly everything. I transmitted several times and got responses back from hams up and down the east coast: Virginia, Florida, and New Jersey.

A portion of the exchanges captured are below:

00:00:01:49 : RS0ISS]CQ,qAO,K4KDR-15:]ARISS - International Space Station

00:00:01:49 : N1RCN-6]CQ,RS0ISS*,qAO,K4KDR-15:=2701.15N/08202.30Wy de n1rcn EL87 Florida
00:00:02:10 : K4KDR-6]CQ,RS0ISS*,ARISS,qAO,K4KDR-15::KM4TJO :Heard you via ISS in Montpelier, VA FM17es
00:00:02:13 : N1RCN-6]CQ,RS0ISS*,qAO,N4WXB-10::KK4DSD :de n1rcn EL87 Florida
00:00:02:18 : KM4TJO]S6TU8Q,RS0ISS*,WIDE2-1,qAO,K4KDR-15:'h&Vl -/] Eric's D710G=
00:00:02:25 : KK4DSD]CQ,RS0ISS*,qAO,N4WXB-10:=3408.45N/08052.30W-73 via Satellite {UISS54}
00:00:02:42 : K4KDR-6]CQ,RS0ISS*,ARISS,qAO,K4KDR-15::VA3TYB-7 :Heard you via ISS in Montpelier, VA FM17es
00:00:02:54 : VA3TYB-7]T4PT1X,RS0ISS*,BIRDMY,qAR,KA8YES-6:'k6sl \YK]CQ CQ Looking for APRS QSOs, live op!=
00:00:03:00 : K4KDR-6]CQ,RS0ISS*,ARISS,qAO,K4KDR-15::KK4DSD :QSL - 73!!
00:00:03:06 : KK4DSD]CQ,RS0ISS*,qAO,K4KDR-15::K4KDR-6 :59 de KK4DSD, 73
00:00:03:09 : WA2NDV-4]APRS,RS0ISS*,qAO,K4KDR-15::KK4DSD :Copy you in FN30 QSL 73
00:00:03:15 : K4KDR-6]CQ,RS0ISS*,ARISS,qAO,K4KDR-15::KK4DSD :Heard you via ISS in Montpelier, VA FM17es
00:00:03:20 : KK4DSD]CQ,RS0ISS*,qAO,K4KDR-15::WA2NDV-4 :59 de KK4DSD, 73

I was also spotted on both aprs.fi and the ARISS stations heard page:

To say I was over the moon, would be an understatement. I’m looking forward to doing this again, preferably using QRP! The best part is, it doesn’t take any crazy or expensive gear to do it: An old 2-meter rig, a cheap mag-mount antenna, some free software and a sound card is all you need.