PL tones for contacting ISS?

[KK7BIV]

Recently, I've been figuring out how to contact the ISS (see thread "ISS tracker website broken?"). I found a website called ariss.org, and they have the uplink and downlink freqencies for the ISS. I'm trying to figure out which frequency to use for FM voice, since I don't use packet radio. I'm not sure if it's 144.49 or if I should use 145.99?

The following frequencies are currently used for Amateur Radio ISS contacts (QSOs):
Voice and SSTV Downlink: 145.80 (Worldwide)
Voice Uplink: 144.49 for ITU Regions 2 and 3 (The Americas, and the Pacific and Southern Asia)
Voice Uplink: 145.20 for ITU Region 1 (Europe, Russia and Africa)
VHF Packet Uplink and Downlink: 145.825 (Worldwide)
UHF Packet Uplink and Downlink: 437.550
VHF/UHF Repeater Uplink: 145.99 (PL 67 Hz)
VHF/UHF Repeater Downlink: 437.80

Thanks!

 

[n5ims]

It depends on which mode they're in at the time of contact. The ariss.org site shows what mode they're in and when you can expect it to change and to what mode.

Typically when the ISS is in cross band repeat mode, you'll use 145.99 with the PL of 67 Hz.

The 144.49 frequency is for special operations that the typical ham will not use. These are the school contacts with the ISS and similar operations. These special operations are planned out months in advance and only the specific ground crew(s) are allowed to make contacts at the time. If a unauthorized ham does attempt to make contact, they will not be answered and if their transmissions interferes with the planned event, folks will not be happy and the offending ham(s) will probably hear about it in a serious way. While it is typical that the contact with a school in your area will be done using hams in your area you can't guarantee that. The scheduling is fairly complex so the contact may be made when the ISS is not in radio range of your local area so hams in another area are handling the communications and the link with the school will be done using a telephone or internet link. The transmissions between earth and the ISS are still done using ham radio but if needed, the link between the hams and the school may use different modes.

 

[wd9ewk]

The 144.49 frequency is for special operations that the typical ham will not use. These are the school contacts with the ISS and similar operations.

This is not correct.

The 144.490 MHz uplink is the one hams will use, paired with the 145.800 MHz downlink, if crewmembers are using the ham stations for unscheduled contacts over ITU regions 2 and 3 - the Americas, along with much of Asia (excluding the ex-USSR countries) and the Pacific. No tone is used on the uplink in this configuration, but it is rare to hear ISS crewmembers pop up and make unscheduled contacts with hams on the ground. I used the 144.490/145.800 MHz pair when I talked with an ISS crewmember from a hamfest near Tucson AZ in late 2018:

IIRC crewmembers can also pick up the mic and join in when the cross-band voice repeater is active. Our uplink for that is 145.990 MHz with 67.0 Hz tone, but I have not heard that happen since the new radio with the cross-band repeater mode was activated.

School contacts will use other unpublished frequencies for the uplink, but in rare circumstances they might use 144.490 MHz for their uplink. And, on some occasions, the school contacts will shift over to the 70cm band, sometimes to avoid interfering with another activity like an SSTV operation on 145.800 MHz.

73!

 

[KK7BIV]

The 144.490 MHz uplink is the one hams will use, paired with the 145.800 MHz downlink, if crewmembers are using the ham stations for unscheduled contacts over ITU regions 2 and 3 - the Americas, along with much of Asia (excluding the ex-USSR countries) and the Pacific.

Yeah, that makes sense. I think if it was a special frequency, they probably would have said something on the website.

But if unscheduled contacts are rare, then I should probably wait until a local hamfest or something like that. I'll see what I can find in the way of local events and things like that.

Thanks, 73 to you too!

 

[Bustergrn]

What a cool experience! I'm sure to HAMs that have been around a while, this is old hat but for someone just getting into the hobby, this is really cool. Thank you for sharing!

 

[n3zra]

There is a VHF up UHF down repeater on the ISS that is on and active for amateur use. It is 145.990 PL 67.0 uplink with a 437.800 downlink +/- for the doppler shift. The current status of the repeater can be found here https://www.ariss.org/current-status-of-iss-stations.html
I hope this helps with what you were looking for.

 

[N4DJC]

@wd9ewk for those that aren’t familiar with satellite operation, is one of the best. He’s helped many amateurs over the years. Listen and learn