A Website For Getting Satellite Passes From Multiple Points on the Earth

Over the last few days, I’ve been developing a website that can determine satellite passes given multiple points on the Earth’s surface. As someone who lives on the coast, this is useful for me as it can be used to plan intercontinental communications with other hams. The software is very modular, and allows a near infinite amount of points to be added, not just the two I was initially aiming for.

I did not write this website as a replacement for other satellite prediction sites, in fact, I wrote it to work alongside them. Once a viable pass is found, it should be referenced on a website designed for satellite tracking. My personal favourite is Heavens Above, but there are others available.

Points can be added by clicking anywhere on the map. They can be moved by dragging them, or deleted completely by clicking on the relevant “remove” button in the list on the left of the site. Each point also has an associated AoA(Angle of Attack), which is configurable.

Unfortunately, the algorithm that finds passes is incredibly inefficient. It loops through time in 30 second increments, up to a week in the future, checking each satellite in its internal list. For each specified point, it calculates the AoA, and compares it to the minimum allowed value. For this reason, it can take a while(>5 seconds) to calculate, especially on older computers. I may optimize this function in the future.

The website is up at https://ham.scd31.com.
The git repository is up at https://git.scd31.com/laptopdude90/multipoint-satellite-tracker.

73 VA1QLE

6 thoughts on “A Website For Getting Satellite Passes From Multiple Points on the Earth”

  1. Hi Stephen,

    Just worked you on SO-50! Would love to exchange QSls with you as your grid is a new one for me. I am sure others that you work would like to do same. However, there is no mailing address listed for you on QRZ.com website and you are not signed up with Logbook of the World (LotW). Lotw is quickest and easiest way to exchange QSL information by far, but I can still send you a paper QSL card as well, if you want. If you need help with signing up or have an address to mail to, please let me know.

    As for tracking, A lot of folks use SatPC32 on their computers and they can hook up their rigs and antenna controllers at a home station. When in the field, I use AMSATDroid on my tablet and at home I have links to different satellites on the N2YO.com website. I use it both in realtime to track my rotors manually as well as use it for sat predictions. I also have an older program called Orbitron that I use for predictions when I want to see multiple satellites at one time. maybe you will find some of these interesting.

    Anyway, welcome to ham radio and to the satellites! Please contact me by e-mail with any info to share of if i can be of any help. 73!! Kevin N4UFO

    1. And I have played with your website a bit… very nice! I don’t currently have a way to show ‘mutual window’ passes, so this will be very helpful! Thanks!!!

    2. Thank you for the kind words!

      I’m still new to satellite work, and ham radio in general, so I’m learning the protocol still. By far, the hardest part for me is being able to hear someone say their callsign and put it into memory, even if it’s just for a second so I can use it in my response! I’m sure that’ll get better as I go.

      I’m signing up for LotW now, I’ll let you know when I’ve done that. The reason I don’t have my address listed is because I don’t send out QSL cards myself, so I didn’t think many people would send them to me.

      73! VA1QLE

  2. Very good! LotW will likely be most welcome by anyone you work. many satellite ops have the disease of ‘chasing grids’. And yes, the ‘remember calls’ issue comes easier with time. Many operators have voice recorders to capture the pass and listen back later. I do that when not at home where I have a notepad in front of me. =^)

    You might want to share your web address with folks on the AMSAT-BB… it goes all over the world. Also a good source of help for perfecting features, etc. I know how important that can be. While I don’t program any more, I did program in BASIC, ForTran, Assembler and some COBOL back in the day at university. Year later I taught myself some PERL to fix a script after another programmer didn’t get it quite right. =^) My first tech job was installing CP/M systems, if that tells you how old I am… WYSIWYG! 73!!

    1. Just sent it to AMSAT-BB, at least I think I did. Not entirely sure. I guess we’ll see!

      I keep meaning to use a voice recorder, but I always end up nearly missing the passes so I’m always in a rush and forget. Oh well, I’ll remember one of these days… 🙂

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