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My favorite ham activity is making contacts via satellites. Not only is there the romantic notion of sending messages into outer space, but you have to trace the orbit of the satellite with your antenna while tuning the radio, to compensate for the Doppler effect.

The satellites AO-51, SO-50, and AO-27 orbit the Earth acting as repeaters. Repeaters are automated relay stations that allow hams to send signals over a greater distance using low-power hand held transceivers. The satellites allow hams to relay messages from Earth to space and back to other hams somewhere on the planet. The International Space Station (ISS) also has a repeater, but occasionally, if you’re lucky, the astronauts turn on their radios to make contact directly with hams on the ground.

The following instructions will get you started listening to birds (satellites) on FM, which can be done with a simple VHF/UHF FM radio with a whip antenna, without the need of a ham license. For better coverage, you can use a Yagi antenna (like the one pictured above) connected to a mutli-mode radio and a license (if you want to transmit). A Yagi antenna can also be used to improve the signal of your hand held radio.

Materials
All you need is a VHF/UHF FM receiver (like a police scanner) or a VHF/UHF transceiver (like a Yaesu VX-7) and an antenna.


1. Specifying your location

Start by visiting Heavens-Above.com to check the orbit of the satellite you want to listen to and specify your location.

2. Specifying a satellite
Check the passes of your specific satellite or the ISS. AO-51, SO-50, AO-27, ISS. Make sure that the passes are shown for your correct location.

satelliteschart.jpg

3. Reading the chart
This pass chart shows the Start (when/where the satellite enters on the horizon), the Max. Altitude (when/where the satellite is at its highest point in the sky), and the End (when/where the satellite finishes it’s pass). Alt. is the altitude, the angle of the satellite from the observer’s horizon. 0 degrees is exactly on the horizon, and 90 degrees is directly above the observer. Az. is the Azimuth, the cardinal direction of the satellite from the observer’s point of view.

4. Picking a good pass
Satellites orbit the Earth at all sorts of angles, some that are very close to the horizon and some that are directly overhead. It is much easier to hear a satellite that passes directly overhead. To find a good sat pass, check the Max. Altitude Alt. for a pass that is 45 or higher (the higher the better). In our example, the second pass at 7:28 looks like a good one since the Max. Altitude Alt. is 77. The first pass at 5:52 has a Max. Altitude Alt. of only 12 which is very close to the horizon and difficult to pick up.

5. Finding the frequency
Satellite repeaters work with two different frequencies, an uplink and a downlink. You will listen to signals received on the downlink. If you wish to transmit, you’ll need to program in the uplink frequency as well. Follow the corresponding links to find the FM repeater frequencies of the satellites. The frequencies often change, so be sure to check the websites for the latest updates. AO-51, SO-50, AO-27, ISS. Tune your radio to the downlink frequency and you’re ready to go outside and listen (example: 435.300 MHz FM).

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6. Aiming a whip antenna
If you’re using a whip antenna, you will not aim the antenna directly at the satellite. Instead, you’ll keep it perpendicular to the satellite. You can rotate the antenna by rotating your wrist to try and get a clearer signal.

7. Following the pass with the antenna
You will trace the path of the satellite orbit with the antenna using the Heavens-Above pass chart as a guide. At the Start Time, start with the antenna perpendicular to the Az. direction at the given Alt. For example, at 7:28, aim the antenna perpendicular to north at 10 degrees above the horizon. Trace the path of the satellite so that at the Max. Altitude Time the antenna is pointed in the corresponding location. For example, at 7:33, the antenna should be perpendicular to west northwest at 77 decrees above the horizon. Finish tracing the path of the satellite so that at the End Time the antenna is perpendicular to the corresponding location. For example at 7:39, the antenna will be perpendicular to south southwest at 10 degrees above the horizon. It can be very difficult trying to catch the satellites and you may spend a lot of time not hearing anything. As you trace the general path of the satellite with the antenna, move the antenna around in small side to side and up and down motions until you hear a bit of audio. Adjust the antenna to make the audio clearer.

8. Tuning the radio for the Doppler effect
The Doppler effect makes the frequency vary by .010 MHz. As you trace the path of the satellite with the antenna, you will also need to tune the radio back and forth plus or minus .010 MHz until you hear a good signal. Early in the pass, you will add .010 MHz, for example, if you’re listening on 435.300 MHz, you’ll need to tune the radio back and forth between 435.300 MHz and 435.310 MHz. Later in the pass, you will subtract .010 MHz, for example, you will tune the radio back and forth between 435.300 MHz and 435.290 MHz.

Here is an audio clip from my first satellite contacts. The contacts seem to be going pretty slowly, but while I was making them, I remember everything happening very quickly. It was a lot to tune the radio and maneuver the antenna while trying to write down the call signs of the contacts.

dianaeng

Fashion + Technology
Diana was a contestant on Project Runway season 2, graduated from RISD, and currently lives in New York City.


Related

Comments

  1. Tad says:

    Thats a really nice antenna. Are there any plans online to make one? I can only see the one coax running to the radio, are you using a diplexer to feed both antennas, or some other method, like 2 separate radios?
    I have an Arrow II antenna, still figuring out how to properly communicate with satellites with it, dealing with a dual VFO radio while also listening for contacts AND remembering to right them down is too much for my brain.

    Tad

    1. Thomas Stuart says:

      That design looks like the classic “cheap yagi” http://radio.obarr.net/downloads/cheap_yagis.pdf
      It is a simple to make J driven antenna that isn’t too fussy about element material or length. In this case there are VHF and UHF elements 90 out of phase, it looks like they are using a 1/4 wave (for the 2 meter band) piece of coax as a band splitter. I could be wrong about that, so please correct me if I am!
      I have used this design many times to work the low Earth orbit (LEO) satellites. I fact I only used a 2m 3 element antenna for both up and down, losing a bit of early and late pass, but still making many contacts. (you are recieve only for the 70cm band, so not so worried about matching that)
      Best pass: Barrow, AK to Seattle WA on 5 watts.
      Funnest pass: Working a pass in the fast food drive thru!

    2. Gordonjcp says:

      The aerial looks like a WA5VJB “Cheap Yagi” design, with those distinctive J-shaped driven elements. These can be built on a wooden boom very cheaply and easily.

      I built mine using brazing rod for the 5-element 70cm aerial and 6mm aluminium tubing for the 2m reflector and director with automotive hydraulic pipe for the 2m driven element (because I had loads of it and it was easy to bend – a bit too easy really).

      For the diplexer (a duplexer is something altogether different) I used the HB9ABX design.

      The aerial took a bit less than an hour to build, and works well. It’s also handy for terrestrial communications. I use it with a Kenwood TH-F7E for satellite contacts and also receiving cubesats and other experimental satellites – I recorded the clip on the Wikipedia page (http://en.wikipedia.org/wiki/Omid) for Iran’s Omid satellite with this equipment!

      Gordon 2M0YEQ

    3. Chris Matthieu says:

      I agree with Tad that it would be fun to make this dual band yagi antenna! I just linked to this post from http://73s.org, our social network for ham radio operators. There are many satellite enthusiasts there as well.

      Keep up the good work Diana!

      73s,
      Chris
      http://73s.org/n7ice

    4. Kent Britain WA5VJB says:

      Hi Tad:

      You can have your choice of about 30 different
      variations of that antenna.

      http://www.wa5vjb.com

      Referece Section

      LEO

      Good luck with your project.
      Kent WA5VJB

  2. Anonymous says:

    Nice.

    1. John Kiniston says:

      @Anonymous

      We get a cool article on satellite tracking full of useful information and all you can comment on is the Diana’s clothing?

      That’s kinda sad and shallow.

    2. Patrick B` says:

      I thought she looked hot. Jackass.

  3. Justin (AJ4MJ) says:

    Diana – Nice job on the antenna. What’s your callsign? Hope to work you soon.

    Tad – A couple of tips.

    1) Don’t touch your uplink frequency during the pass. No need to change it and leaving it alone gives you only one VFO to worry about.

    2) Get a digital voice recorder (or microcasette recorder) and record the passes so you can write them down later. Or, just don’t worry about logging your contacts. Less stressful that way :-)

    -73

    1. Kenneth Finnegan, W6KWF says:

      Her call is KC2UHB, which I got from the audio clip linked in the last paragraph. Thanks for the guide Diana, always have wanted to get into birds.

      1. Sneaky Rupert says:

        Well crud…I went all the way to QRZ to find the same thing!

  4. Ollie AJ1O says:

    Additional information about using ham radio satellites can be found here:

    http://www.amsat.org/amsat-new/information/faqs/

    Have fun!

  5. John Kiniston says:

    @Diana Eng Very cool article, Any info on the Yagi your using? What did you use for your audio recording?

    John Kiniston
    KE7TRL

  6. dennis says:

    nice antenna? I was too busy noticing the sweet girl.

  7. Ollie AJ1O says:

    Why did this article vanish from the Make blog home page?

    1. Ollie AJ1O says:

      It’s there. User error :)

  8. Sneaky Rupert says:

    Google for “Kent Britain Cheap Yagi”. Looks like a similar design and it performs well (I have built a few).

  9. gladeye says:

    I don’t mean to sound snarky or disrespectful, but I listened to her recording and I’m not sure I get the point of it. I just heard people reciting their call letters to each other, but not talking about anything. Is the entire appeal of this hobby the collection of call letters? Do you even find out where they are coming from? It’s a nice technological feat, but what do you DO with it?

  10. Justin (AJ4MJ) says:

    Gladeye,

    Great question. I had a very long response to this which the website ate, so here’s the short version:

    * The callsigns and grid squares you hear being exchanged do mean something. From the station’s call sign (3, 4, or 5 letters and one number) you can look up their name and address and send them a postcard to confirm the contact. The grid square, (two letters followed by two numbers), indicates the station’s position and can be looked up.

    * The FM satellites that Diane is using only allow one conversation at a time and only pass over the country for 10 minutes at a time. So, they tend to be very busy and being terse is essential so that everyone gets to use the bird. There is another type of satellite that allows for multiple conversations and on those birds the conversations are more casual.

    * Many ham operators like to postcards from unique countries, states, counties, and grid squares. They submit them for awards. Not really my thing, but it does provide a goal-oriented challenge that is popular.

    * Satellites are but one aspect of ham radio. Most ham radio is done via ground-based stations where there is more time to talk. These QSOs can go on for hours and may be one-on-one or group “round table” conversations. Topics range from radios, family, health, weather, other hobbies, and even politics (for those with a strong stomach).

  11. Justin (AJ4MJ) says:

    Thanks. I was reading this at work and couldn’t play the audio without everyone knowing I was goofing off :-)

    1. Greg Roper says:

      Nice callsign Justin.

      Greg
      AJ4FJ

  12. Anonymous says:

    One more comment for Dianna and others attempting this. She is using a FT-817 rig for this, which I also own. The user manual gives an example of programming in 5 or so pairs of frequencies(Tx/Rx) into the memories to deal with doppler shift. I thought it was a clever way of getting around the dreaded doppler tracking issues.

  13. Kent Britain WA5VJB says:

    I must say I’ve never seen one of my desgins look
    so good!

    You can download over 30 variations of this antenna
    at http://www.wa5vjb.com Reference Section LEO Satellites

    Yes, the diplexer is intergral to the antenna and
    is mainly #18 guage wire using a pencil as the coil
    form.

    Interesting use of ear plugs!

    Kent WA5VJB

  14. James says:

    How hard would it be to modify the WA5VJB cheap yagi antenna’s for different frequencies? The 2-meter one especially since there’s the warning not to use it above 146.something or else. :/

  15. Jack says:

    Some radios will track the signal for you and also the antennas will track the sat.

  16. Orion says:

    A really cool article! I’ve always been interested in ham radio right from childhood, reading about it in the library, now I want to stop dreaming and start living! So I would really be grateful for advice on how to take my first baby steps (‘ham radio for dummies’ if you get what I mean) into this amazing world. I always think of it as the first ‘internet’. I’d prefer advice on homebrew as I think it would be cheaper not to mention way more fun to build and use my own equipment. Some of you may say I should go check Google but I’d also like first hand advice (but useful links are welcome). So please, do talk, no matter how little, no advise is trivial. PS: I used to know those birds as OSCARs, or is that name obsolete?

  17. Orion says:

    Also, do you think its a good idea for me to start with listening only?, so as gain a little experience and whet my appetite before I can get a license, which I doubt will be anytime soon due to engagements.

  18. Wm. Keith Hibbert says:

    Hi Diane, Keith, WB2VUO near Buffalo, NY

    Surprisingly, you and your dual-band beam showed up on the Amateur Radio Antenna group on Flickr, one of the local satellite enthusiasts sent me a link. I am the WNY Section Tech Coordinator for the ARRL and keep track of your page and similar other blogs and sites if I get requests for information on amateur radio subjects.

    Another local ham here in WNY still has a YouTube video on building Eggbeater loops for satellite operations, he’s John, KB2HSH south of me in Elma, NY.

    What’s funny is that I ran the Beginner’s Tech page on a landline and packet BBS in the 90′s. My beginners antenna pages were ported to the Internet by Frank, G3YCC (SK) in the mid-90′s and are still out there in cyberspace. I get 3 – 4 requests for the article each month.

    Andy Warhol talked about everybody getting “20-Minutes of Fame” in their lives, my Haam Radio posts are coming up on 20 Years of fame, and still counting.

    Excellent article, hope to work you on the new AMSAT birds someday…

    73, Keith, WB2VUO, TC – ARRL WNY Section
    Amherst, NY: Grid FN02ox