I hear a lot of people talking about getting in contact with space with their ham radio.

  • What do you hear?
  • Do you talk to astronauts?
  • Or: Is it just an expression?
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    $\begingroup$ ariss.org/contact-the-iss.html $\endgroup$ Apr 30, 2020 at 21:08
  • 1
    $\begingroup$ Please clarify your question, what do you mean by "getting in contact with space"? Are you referring to the International Space Station? Talking to astronauts in space? Or sending packet (text) messages using the Space Station as a relay? Or talking to other hams on earth by sending your signal through satellites? Or receiving images from weather satellites? Bouncing signals off the moon? There's a lot of space stuff out there. $\endgroup$
    – progrmr
    May 4, 2020 at 16:57
  • $\begingroup$ I'm talking about talking to an astronauts $\endgroup$ May 4, 2020 at 17:02

3 Answers 3


ISS has amateur radios on board. Sometimes they even work. Sometimes they're on. Sometimes when they are on, there is an astronaut talking on it. Details, schedules, frequencies, etc., can be found on the ARISS contact page (credit Greg Hewgill, thanks!)

Over the years, the amateur radio equipment on ISS has been replaced, repaired, and broken repeatedly, but usually there's something there that works. (My impression is that the most common damage is the memory in the radio being scrambled by cumulative space radiation.)

When the radios are working, and the astronauts remember to leave them in the right mode, it is possible to contact the radio and get an automatic response. Occasionally they are put in a transmit mode, repeating an automated message (such as SSTV images).

When astronauts with amateur radio licenses have downtime and want to talk to someone in the real world other than NASA controllers and their family, sometimes they will talk to people through the ARISS equipment.

ISS is in what is called a low Earth orbit. As a consequence of this, it is only within radio contact with a location on the surface for about 9 minutes at a time before it goes over the horizon. Longer contacts require relays.

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    $\begingroup$ To elaborate on the automatic response, one radio on the ISS is usually set up as an APRS (Automatic Packet Reporting System) digipeater. Hams transmit APRS packets on 145.825MHz, which are relayed by the ISS or another amateur radio satellite and these are picked up by ham gateway stations which report them to the APRS-IS (Internet System). ariss.net shows a list of stations and their messages which have recently been digipeated via ISS or satellites, and amsat-uk.org/beginners/how-to-work-the-iss-on-aprs-packet-radio has links to several articles on how to do so. $\endgroup$
    – MoTLD
    May 1, 2020 at 1:12
  • $\begingroup$ I didn't feel like going into that much detail, thanks. I thought also they occasionally did crossband repeat or something too. $\endgroup$
    – user10489
    May 1, 2020 at 5:26
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    $\begingroup$ In addition, sometimes there are scheduled events, usually for school-children, where an astronaut talks to a group of people. $\endgroup$
    – Pete NU9W
    May 1, 2020 at 12:06

The only astronauts that currently have amateur radio on board are the ones on the International Space Station (ISS). The MIR Space Station and the Space Shuttle used to have ham radio but they are no longer operational.

It's rare that you can talk to the astronauts, for several reasons, but it is possible. They have a full schedule of work and are very busy. From time to time they do arrange a schedule to talk to schools and do question and answer sessions.

If they have free time in between their work hours and sleep hours, they may choose to operate the radio and chat with people. It doesn't happen often and you won't be able to talk to them unless they happen to by flying overhead at that time.

As explain on the ARISS web site, when they do get on the radio, the astronauts operate split frequency, where you transmit your voice signal to them on 144.49 Mhz (the uplink for you in region 2) and you listen for their reply on the voice frequency 145.80 Mhz (the downlink). This is a normal FM voice signal that any handheld 2 meter radio can do.

In theory you could talk to them with a 5 watt FM handheld radio, but in actual practice it is probably not enough. With FM radio they will only hear the strongest signal (called capture effect). A lot of hams monitor the 145.80 download frequency and if they hear the astronauts are on, they will call them. The astronauts will only hear the strongest signal, about a 500 mile diameter circle below them. If 50 hams in that area all call them at once, only the strongest signal will be heard.

If you want to monitor the downlink frequency and listen for them, you need to know when they are passing over. It's only for a maximum of 9 minutes, probably 2 or 3 times per day. Miami is about 28.2 degrees N latitude and 80.2 degrees W longitude, so you can use a web site like AMSAT's Online Pass Predictions to find out when to listen. Select ISS, enter 28.2 North latitude, enter 80.2 West longitude, elevation 0, and get predictions. Look for the passes where the elevation is at least 10 degrees (below 10 is a short pass, weak signal since they are too close to the horizon).

Your best chance would be to find passes over you that coincide with their free time periods and listen for them then. Keep up with ARISS news to know what is happening with their radio equipment and who is on board.


You can try https://www.n2yo.com/?s=25544 to track the satellite. But I see in your posts that you live in Miami, and the ISS doesn't usually pass over there, so it might not be possible

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    $\begingroup$ That's not correct, ISS passes over Miami area daily. $\endgroup$
    – progrmr
    May 3, 2020 at 12:05

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