[Video] New UHF ISS Digipeater!


I also made my first contact through it today:


While I was making the above video, I randomly picked up the digipeater in
my apartment:


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Recently, the old VHF Ericsson handheld used for the digipeater on the ISS died and it was replaced with an equivalent UHF one. This is my first time digipeating through it.

I also tried to make my first APRS satellite contact. I successfully sent a message to the digipeater for another ham, KM4SYN, but he didn't receive it from the ISS. He did however receive one of my beacon packets and you can see me on his map.

The "Programming TH-D72 for ISS Digipeater" video will be uploaded next week.
I made this recording on November 2nd, 2016, shortly after the UHF digipeater was activated.

Thanks for watching!

73, John Brier KG4AKV

The music at the end is Cybotron - Clear, a classic electro track.

KG4AKV – Thu, 2016 – 12 – 15 23:29

Jorgen OZ1MAS

I only have one Christmas wish this year and its to get ISS back on 145.825 MHz please please Santa

Submitted by Jorgen Mortensen on Wed, 2016-12-21 13:50.

ISS digipeater moving back to 145.825?


I think we all would like that, but you will have to be patient. It will be a little while before a radio with VHF is taken up to the ISS for the Columbus module. Until then, it is possible to work the 70cm digipeater. Seems like more are doing this here in North America than in Europe.

Good luck, and 73!

Twitter: @WD9EWK

Submitted by WD9EWK on Thu, 2016-12-22 11:39.


Hi all

Happy New Year !

I'm a newbie in ISS packet receiving, so new tjat I even have not recieved any packet signal (437.550)
Is ISS active those days ?

I installed Soundmodem and UISSv5.4 on my PC and have been monitoring during the EU passes .... so far nothing ....

73 Danny ON4VT.be

Submitted by ON4VT on Mon, 2017-01-02 11:16.


Hi Danny!

Yes, the ISS packet digipeater has been active on 437.550 MHz. You will have to compensate for Doppler on transmit and receive. For many using channelized radios, a group of 5 memory channels will allow for this. I have been doing this on my TH-D72 and TH-D74 HTs, and many others have been doing the same thing for the past couple of months.

The frequency chart I have been using is available from AMSAT at:


Or you can see it on my @WD9EWK Twitter feed:


What radio and antenna are you using? Many who used vertical antennas for the ISS on 145.825 MHz may not work so well for 437.550 MHz, especially if that vertical antenna has lots of gain. Antenna polarization seems to be more important on 70cm that it was on 2m, even for those using handheld Yagis or log periodic antennas.

BTW I think I worked you on 20m RTTY back in 2000. I used WD9EWK/7 on HF digital modes back then, and received an LOTW confirmation for that QSO.

Happy 2017, and 73!

Twitter: @WD9EWK

Submitted by WD9EWK on Mon, 2017-01-02 15:40.


Hi Pat

Great to hear from you again ! hi. In the meantime I've been qRT for more than 10 years but getting medically retired I started up this fantastic hobby again! More info and photos on my QRZ page.

For RX ISS I'm using a Yaesu FT991 with a Diamond AX300 vertical. For SSTV reception that worked out well (VHF though). The radio is not channelized so I will try again on the other frequencies (Doppler) on the next passes.

Thank you for the useful information ! Have a happy New Year and hope to work you again soon. I'm very often QRV in Olivia and JT modes, all bands 160m to 70cm ...

73 Danny ON4VT

Submitted by ON4VT on Tue, 2017-01-03 08:14.


Hi Danny!

You can program memory channels in an FT-991. I saw this described in a PDF copy of the FT-991 Operating Manual, as "Split Memory". There is software like SatPC32 available from AMSAT-UK or AMSAT in the USA that can control your radio, so you won't have to program memory channels.

Your vertical antenna may have a lot of gain on the 70cm band, but that gain is coming at a price - the radiation pattern. Most of the signals are being kept close to the ground, and not radiating upward where the ISS would be. Many who have been using 2m/70cm verticals with good results on 145.825 MHz (the frequency previously used by the ISS packet digipeater) are finding poor performance on 437.550 MHz.

One suggestion would be just to listen to the downlink as the ISS passes overhead. Set your VFO to 437.560 MHz FM, and slowly tune downward to end up on 437.540 MHz at the end of the pass. Use a combination of your ear (does the signal sound off-frequency?) and watching your packet software (is it starting to have problems decoding packets on whatever frequency you are on?) to know when to adjust your receive frequency.

Good luck, and 73!


Submitted by WD9EWK on Tue, 2017-01-03 11:50.

TNX hint

OK gonna try that one !

You will hear it when I got the first packet decoded !

73 TNX Danny ON4VT

Submitted by ON4VT on Wed, 2017-01-04 11:04.

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