Cool Stuff, DX, Operating

Hi Juno After-Action Report

As I write this, the Juno spacecraft has completed its slingshot maneuver around Earth, having stolen a bit of Earth’s rotation energy. and is now on its way out to Jupiter. A bit before the designated 1800 UTC start time for the event, I was able to set up my Icom IC-718 at the appointed frequency of 28.324 MHz with an output power of approximately 60 watts CW.

I executed the hijuno.py script via SSH (as mentioned in my last post) a few minutes shy of 1800, turned on my handheld scanner so I could monitor the transmit frequency, and waited for the show to start. I also checked a few WebSDR receivers to see if I could detect how many hams were participating in the Hi Juno event.

Hi Juno Website
Hi Juno Website

The transmitter started up, but immediately I could see that it wasn’t in sync with other stations that I could hear and see on the receiver. My shack PC is running Ubuntu 13.04 and it set up to automatically set its clock via NTP, but obviously it was off by quite a bit. So I had to duck into the shack quickly to manually update NTP, then come back to my laptop to restart hijuno.py via SSH. This time, I could see by following along with the interactive Hi Juno website and listening to my transmit monitor, that my timing was correct. As you can see above, the website had a nice graphical display of when to key up and key down for those doing this manually. That little yellow triangle at the bottom of the screen moved from left to right to indicate the current position within the transmit timing window.

W5ZA WebSDR
W5ZA WebSDR

At this point, satisfied that the Python script seemed to be working, I went back to WebSDR for a listen. The W5ZA 10 meter beacon receiver in Shreveport, Louisiana seemed to be a great choice for monitoring all the Hi Juno signals out there, probably because it was still in daytime, as opposed to the European receivers, which seemed to be showing nothing. Normally this would be considered bad, but I have to think in this case it was a good thing, since the ionosphere was probably not reflecting 10 meter signals back to Earth in this part of the world, and they were free to make it to Juno. To the left, you can see a screen capture of the W5ZA WebSDR just after a Hi Juno keydown period.

The rest of the event was fairly…uneventful. The Python code worked perfectly and stopped transmitting at the right time. It was fun chatting on Twitter with other hams who were also participating in the event. Based on watching the WebSDR waterfall and checking Twitter search, it seemed like there were quite a bit of us taking part in the event. I have no idea, how long it will take for us to hear back from the investigators whether this worked or not, but I hope it’s fairly soon. I’m definitely looking forward to getting a QSL. My first one from an interplanetary spacecraft. I also have to say that the Hi Juno website worked wonderfully during the event with its simple and clear graphic instructing you when to transmit, and showing you transmit window. if we ever get more opportunities to participate in experiments like this in the ham community, it should be a model on how to run things. Even though we didn’t get any immediate gratification, it was a fun event and I hope that NASA/JPL reaches out to us again in the future.

Coding, DX, Homebrewing

Hi Juno!

As a world-class procrastinator, I know I’m very late with this post only about 12 hours before the event. However, I still wanted to share it with you in the hopes that maybe it could help one person.

As you may have heard, the Juno spacecraft will be making a close approach to Earth on 9 October 2013 as it slingshots to gain energy for the trip to Jupiter. The investigators who are in charge of a radio receiver on the spacecraft wish to see if they can detect intelligent life on Earth who may be transmitting on the 10 meter band. Therefore, they are asking licensed radio amateurs to transmit a slow-speed CW “HI” signal to Juno during a window at Juno’s closest approach. The full details are on the Hi Juno page (due to the US government shutdown, the primary page is offline, but the event is still planned to take place).

BWFZtUsCcAA8RgFIn order to be able to take part in this event without having to be right at the transmitter (I have to take care of my two toddler boys during the specified time period), I wrote a program in Python which will automatically transmit at the appropriate time. You just need a PC synchronized to NTP time, a 10 meter CW transmitter, a serial port, and a keying interface (which I will describe shortly). I plan to execute the program on my shack PC via SSH and monitor my transmissions on a portable receiver to maintain control of the transmitter.

Serial Port Keying Circuit
Serial Port Keying Circuit

Here is the simple keying circuit I use to key my Icom IC-718. It should work with just about any grounded keying transmitter, but as usual your mileage may vary. I use a DB9 female jack for the serial port. The RTS line is used to turn on a 2N7000 MOSFET, which will ground the key line in order to transmit. You can use any key jack that is appropriate for your transmitter. I use this circuit with a USB-to-Serial adapter, and it still seems to work fine.

The actual Python program to control the serial port keyer is found here at GitHub. You will need to have the PySerial module installed on your system, in addition to the regular Python installation. I’ve tested it here, but please be sure to test it yourself on a dummy load before using it on the air (you will need to temporarily change the START_DATE variable to an earlier time in order to get the program to transmit). You will also need to change the DEVICE, BAUD, and CALLSIGN variables to values appropriate for you. Linux/OS X users would change DEVICE to whichever “/dev/tty*” port is appropriate, where the * is your port numbe. Windows users would use “COM*”, where * is the COM port number. Sorry that I can’t hold your hand through this, but it should be fairly simple to get running. Linux and OS X users may also have to execute the program under sudo in order to access the serial port.

Please let me know if you end up using this, and don’t forget to request a QSL from Juno!