●●●● ●● | ‘HI Juno’ Say Ham Operators

The NASA Juno spacecraft is headed for Jupiter. Launched August 2011, it is scheduled to arrive July 4, 2016. On October 9, 2013, Juno coasted by the Earth and used gravity assist to speed it up and redirect it slightly so it will coast the rest of the way toward Jupiter. It received a boost in speed of more than 8,800 mi/hr (about 7.3 km/s). It is currently right on course. You can read about that flyby in this news release from the mission website.

During the flyby of Earth, scientists turned on Juno’s Waves instrument. This instrument will eventually measure radio and plasma waves in Jupiter’s magnetosphere. The reason for turning it on during flyby, three years before reaching Jupiter, was to record amateur ham radio signals. Ham radio operators around the world were invited to take part in a public outreach project. They were invited to say “HI” to Juno during the flyby.  They all broadcast the same low power Morse-coded “HI” message at the same time from their home antennas. Over 1400 operators from every continent, including Antarctica, participated.

Morse code characters use dots and dashes, or “dits and dahs.” To transmit the letter H, operators needed to send 4 dots, or dits, in a row. These were followed by a space in time. Then came 2 dots, or dits, for the letter I to complete HI. As Juno neared Earth, each operator viewed a web page run by mission scientists that told them when to make their dits and how long to hold them. Each dit lasted 30 seconds. The HI message was repeated every 10 minutes for a total of 16 times until Juno had passed Earth.

The green dots at top represent pieces of the repeated message that Juno was able to detect. Grey dots were transmissions, but not detected by the Waves instrument. The ham radio signals were processed to isolate them from the background noise. Scientists on the Waves team were not sure the signal could be detected. When the the recording was played back at high speed, they were thrilled to see and hear the signal in the data.

Bill Kurth, University of Iowa Physics and Astronomy, and lead investigator of the Waves Team, describes the project in this 4 minute documentary. You can hear for yourself how it sounded to Juno. All participants were happy with the success of the team effort.

13 thoughts on “●●●● ●● | ‘HI Juno’ Say Ham Operators

  1. I’m definitely looking forward to Juno reaching its destination! Its Earth flyby, and the images it took of the Earth/Moon system back in October was a highlight of the year for me, as was the ‘Hi Juno’ project. Awesome video!


  2. I hadn’t heard of this project, but as many Ham operators as we have around here, there surely were a good number involved. When I first started sailing I got my general license just for kicks. I could do twelve words a minute, as I recall, but I’d be lucky to send out more than an SOS at this point.

    When I was in Liberia, our pilot was a Ham operator. If we needed to get in touch with the States, we’d go down to his shack and he’d call up someone – usually a fellow in North Carolina – who’d do a phone patch. By the time the process was completed, it felt a little like being on Jupiter.


    • Sorry to have taken so long to reply. We had company all afternoon and evening.

      I don’t think one needs to know M Code these days to get a license. My oldest brother was an operator many years ago. I would listen to him contact people all over and think that was fascinating. It was cool to reach people anywhere. Now look at us. We do it all the time with the internet.

      I like your comment about feeling like being on Jupiter.


      • No need to apologize about taking some time to reply. I think everyone understands that there’s life beyond the blogs, and if they don’t? Well, they can just learn a little patience! 😉


      • Most of the time I am fine with letting it go as I get other things done. I value the comments of certain people more. They take the time to graft some interesting or thoughtful words. I think that is important. Your comments are ones I value.


    • The American Heritage Dictionary says that the use of ham to mean ‘a performer who overacts or exaggerates’ and ‘a licensed amateur radio operator’ may have come from the term ham-fatter, which people once used for ‘a poor or amateurish actor.’ The fat has been lost, and I imagine that ham radio operators are also on the way out in an Internet age when we can write to, hear, and even see each other live online.


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