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ISS digipeater issues?

Discussion in 'Satellite and Space Communications' started by KD0KZE, Oct 21, 2016.

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  1. KD0KZE

    KD0KZE Ham Member QRZ Page

    I saw a message on that the digipeater rig is having issues. Anyone have additional info?

    73, KD0KZE / Paul
  2. KB1PVH

    KB1PVH XML Subscriber QRZ Page

  3. WD9EWK

    WD9EWK Ham Member QRZ Page

    I don't know if the Russians will run packet on their gear. It would be interesting if a radio on 70cm could be used with the packet system on the Columbus module. Have to adjust for Doppler on uplink and downlink, but it could be done. It's a shame the old 2m radio stopped working, as I was just getting started with my TH-D74A on ISS packet - and liking it.

  4. W5SAT

    W5SAT Ham Member QRZ Page

    Agreed - that's a bummer. I always liked the ISS digipeater.
  5. KD0KZE

    KD0KZE Ham Member QRZ Page

    Hopefully they'll get it back up and running. Would be great if the Chinese would consider an amateur radio digipeater on their new space station also.

    73, KD0KZE / Paul
  6. WD9EWK

    WD9EWK Ham Member QRZ Page


    In the past few hours, the ISS packet station in the European Columbus module is back on the air - but not on 145.825 MHz. The Ericsson UHF HT that has been up on the station was put into service today, and packet is now active on 437.550 MHz. This means corrections for Doppler on both uplink and downlink will be required. It won't be as simple as using radios on 145.825 MHz without having to make any frequency adjustments, but it will be a new challenge.

    There is a pass early Wednesday (2 November) morning over the western USA, which I hope to work. I will have a group of memory channels programmed in my TH-D74A to compensate for Doppler, and also turn off the APRS Lock setting so I can change frequencies during the pass. Normally I like the APRS Lock, which keeps my TH-D74A from changing frequency when in APRS mode, but that is exactly what I'll need tomorrow morning.

  7. WD9EWK

    WD9EWK Ham Member QRZ Page


    With the activation of ISS packet on 437.550 MHz, I have programmed my Kenwood TH-D74A with these 5 channels:


    To compensate for the Doppler, the transmit frequency will move up as the receive frequency moves down. The middle channel is basically 437.550 MHz simplex, no special odd-split needed here. The others will either need a receive frequency with small offsets, or independent receive and transmit frequencies as listed above.

    With these memories, you would start on channel 1 from the chart above. You will only be on each channel for a minute or (at most) two, so be listening to the packet. When it starts to sound the slightest bit off, or when you hear what sounds like good signals but nothing is being decoded, it will probably be time to tune to the next memory, and repeating this through the 8- to 10-minute pass.

    Good luck, and 73!
    W5SAT likes this.
  8. W5SAT

    W5SAT Ham Member QRZ Page

    Nice! Thanks for the info, Patrick. I'll have to set up some memories in split mode on my TS-2000 - haven't done that before.
  9. W5SAT

    W5SAT Ham Member QRZ Page


    Thanks to your update, I was able to send a few packets through the ISS on the new frequency. I saw you coming through and eventually got my own packets through. Need to get the split mode working properly on my radios. I only saw you, KK6OTJ and my call signs this pass. Also, doesn't seem like the stations feeding the internet are caught up yet as there was nothing for this pass showing up on

    Signal from ISS was nice and strong - I'm liking that.
    WD9EWK likes this.
  10. WD9EWK

    WD9EWK Ham Member QRZ Page

    I didn't see you on that pass, but I wasn't seeing anything for the last 2 or 3 minutes of the pass. Maybe the 70cm antenna on the ISS is not in a good spot, in relation to my location for that part of the pass. I saw KK6OTJ and AI6GS from southern California on there, and made a quick QSO (exchanging APRS messages) with KK6OTJ.

    I could get into the digipeater at a lower elevation on 70cm than on 2m, using the same radio/antenna combination. Signals were good, and using my block of memory channels worked well - except for not hearing anything near the end of the pass. The audio recorder in the TH-D74A was able to record the received signals, and they sounded pretty good.

    For my group of memories for the 437.550 MHz packet, I got through about 80-90 seconds after AOS using the first memory channel (receive on 437.560, transmit on 437.540). I didn't stay there for more than 60-90 seconds before moving up to the next channel. I was able to see my own signals getting through until 1326 UTC, and still heard signals for about a minute after that before I stopped hearing anything on the frequency. At the end of the pass, I was cycling through channels 3, 4, and 5 to see if I could still get through. Nothing. It wasn't hard to work this pass, similar to how I'd work AO-85 and have to adjust my transmit frequency throughout the pass. The memories made sure the receive frequencies were in sync.

    I will need to try other types of passes, to see if I can do better - or if I have more issues early in the pass - compared to this pass that started to my WSW and went around to NNE. With pass times as they are now, that might have to wait until the weekend. I'm not looking to get on passes before 1300 UTC (6am local time), and can't get on the daytime passes when at the office.


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