Is AO-92 unwell again?

Discussion in 'Satellite and Space Communications' started by KC3RN, Oct 1, 2021.

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  1. KC3RN

    KC3RN Ham Member QRZ Page

    I just tried to work a relatively high AO-92 pass. Heard nothing until the dreaded "Fox 1 Delta Safe Mode" announcement. I've been away from the sats for a few days, so forgive me if this is old news. Is AO-92 okay? Hopefully the control station just gave her a break for a little.

    AO-92 was always my favorite bird, and I was upset when it went offline the first time. Hopefully this is only temporary.
  2. KA2CZU

    KA2CZU XML Subscriber QRZ Page

    Burns Fisher <>
    Sat, Sep 25 at 3:04 PM

    AO-92 has started to change its behavior after a number of weeks powered on. In particular, the IHU has come back on and switched to safe mode. This is likely due to low voltage during eclipse when it should be drawing very little if no one uses it.

    N8MH also reports that he is turning off FalconSat's transmitter for a while due to low voltage.

    The AMSAT Ops team is going to shut both down for a while in hopes they will recover.

    AO-91 still seems to be ok!
  3. KC3RN

    KC3RN Ham Member QRZ Page

    Thanks for the info.
  4. KC3RN

    KC3RN Ham Member QRZ Page

    Just in from Facebook:

    For those of you interested in what's going on with AO-92:
    As you probably know, its batteries have gotten pretty unhappy. Back in the spring, it got to the point where it was going into auto-safe mode (due to low voltage) every eclipse (i.e. once per orbit) but because of a code bug it never came back to standard mode when it came back in sun.

    After giving the batteries some rest, 92's transmitter was turned back on and leaving the IHU off. This puts it in COR (carrier operated repeater mode). That worked well for a while, but now the batteries are no longer keeping alive the command receiver plus the little chip that "remembers" that the IHU is turned off. Thus we got back into the auto-safe/safe mode. Nice telemetry, but no repeater.

    So what we have done now is leave the IHU on, but command the IHU to disable autosafe mode. This means that the repeater is on, and requires the 67Hz tone again, but a) PLEASE DON"T TRY TO USE IT WHEN IT IS NIGHT WHERE YOU ARE, and b) it probably will stop repeating as soon as it goes into the shadow of the earth anyway.

    Batteries can fail shorted, or fail open. If these happen to fail open, we might have a nice long time with AO-92 just as we do with AO-7. But given the relatively low voltage we see even in sun, I'm guessing the batteries are drawing more current than usual and heading toward short, so I'd suggest you enjoy the repeater while you can!

    73 de WB1FJ
    AMSAT Engineering

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