NO-44 Revival: ISS and SONATE APRS Fun

By David Trolinger, N5ZKK | June 4, 2025

A Peak Moment in my Satellite Communications History

In June 2025, the semi-famous NO-44 (PCSAT-1) satellite sprang back to life and I had the thrill of a my satellite operating career. On June 4, I sent an APRS packet from my station in grid EM00, relayed it through NO-44 to the International Space Station (ISS), and watched it hit the internet via ground stations. This was my first satellite packet relay, and it’s what I call peak satellite! Below is the convoluted but exciting story of that day.

Diagram of NO-44 to ISS APRS packet relay path

The Relay Adventure

Over the years, I’ve sent APRS packets through various satellites, but this was special. I noticed that NO-44 and the ISS would be overhead simultaneously, triggering a memory of an experiment to relay packets from ground to PCSAT-1, then to the ISS, and finally to internet gateways. Despite the ISS frequency being congested with the usual traffic, NO-44 heard my packet, and the relay worked!

Stations involved

I used the UISS software by ON6MU, which I’ve been running for ISS and SONATE-2 operations. Previously, I relied on YAAC by KA2DDO on a Raspberry Pi3 as my home digipeater. Here is the screen shot of the NO-44 packet.

UISS

Well IT Probably WORKED

	http://ariss.net/

	00:03:09:35 : N5ZKK]APRS,RS0ISS*,qAR,W0JW-6::W3ADO-1 :VIA NO-44 and ISS
	00:03:10:19 : N5ZKK]APRS,RS0ISS*,qAO,W4TBD-10::W3ADO-1 :VIA NO-44 and ISS

	http://www.findu.com/cgi-bin/raw.cgi?call=N5ZKK

	N5ZKK>APRS,RS0ISS*,qAO,W4TBD-10::W3ADO-1 :VIA NO-44
	N5ZKK>APRS,RS0ISS*,qAO,N0JD-10::W3ADO-1 :VIA NO-44 and ISS
	N5ZKK>APRS,RS0ISS*,qAO,W4TBD-10::W3ADO-1 :VIA NO-44 and ISS
	N5ZKK>APRS,RS0ISS*,qAR,W0JW-6::W3ADO-1 :VIA NO-44 and ISS

Over the next few days I had some more fun when SONATE-2 joined the party

Stations involved June 5th NO-44 SONATE-2 ISS

UISS and Orbitron showing the action during the SONATE, ISS, NO-44 meetup

June 5th NO-44 SONATE-2 ISS

Due to the doppler and the NO-44 drift to 145.827MHz is was unlikely that a relay occured but the main problem was the lack of ground stations in the SONATE-2 footprint as it was over the South Pacific.

June 5th NO-44 SONATE-2 ISS

Screenshots

About NO-44 (PCSAT-1)

Bob and NO-44

NO-44, also known as PCSAT-1, was built by midshipmen at the U.S. Naval Academy under the guidance of Bob Bruninga, WB4APR, the inventor of Automatic Packet Reporting System.

Launched in 2001 from Kodiak Alaska, this 1200-baud APRS digipeater satellite operates on 145.827MHz and has been in orbit for over two decades—a remarkable feat for any satellite.

Launch from Kodiak Alaska

Despite battery issues that cause periodic resets, NO-44 comes alive when its solar panels provide enough power. These windows allow hams like me to work this legendary bird. USS PARCHE

NO-44's role in enabling and inpiring global APRS communications along with Bob's teachings are a testament to his legacy.

Commander Bob Bruninga
Commander Bob Bruninga, WB4APR, SK (1948-2022)

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