Imagine that, no AO-85 celestrak elements... This leaves me positively confused how AO-85 was in my GPredict catalog which only pulls from Celestrak (maybe an old amateur.txt from AMSAT-BB), but whatever. I retract my statement about AO-85 not being overhead then. Using the latest TLE from N2YO I can see it was over KN01wx at that time.
On Wed, May 4, 2022 at 2:00 PM Burns Fisher wb1fj-bb@fisher.cc wrote:
Steve, I believe you are correct that it was left with the IHU turned off. HOWEVER that state is not kept in a non-volatile memory. If the power totally failed (as seemed likely) then chances are that if power came back on, the IHU would be powered on (we saw this behavior in AO-92 toward EOL as it passed in and out of eclipse). But on the other hand, AO-85 is in a bit higher orbit than many and as I recall the IHU was starting to run hotter as we got to EOL, so it is entirely possible that even with power the IHU would not work due to radiation damage. Remember the processor is a straight COTS part.
So regardless of how it was left when we last saw it, there is a chance that we would find it either way.
Burns
On Wed, May 4, 2022 at 1:52 PM Stephen E. Belter seb@wintek.com wrote:
Burns and Robert,
I’m not an expert, but I believe AO-85 has its IHU (Internal Housekeeping Unit, the control computer) turned off, so you shouldn’t expect to hear the DUV (Date Under Voice) telemetry. Instead, if it comes on, AO-85 will be in COR (Carrier Operated Repeater) mode so that the CTCSS tone won’t be required to trigger the transmitter. You should expect to see the “fox tail” characteristics of the Fox transmitters on a waterfall display.
Maybe KO4MA, N8HM, or N8MH can chime in to confirm or correct.
Thanks for monitoring old AO-85.
73, Steve N9IP
--
Steve Belter, seb@wintek.com
*From: *Burns Fisher wb1fj-bb@fisher.cc *Date: *Wednesday, May 4, 2022 at 12:59 PM *To: *Robert Meade rjm27trekkie@gmail.com *Cc: *AMSAT-BB amsat-bb@amsat.org *Subject: *[AMSAT-BB] Re: AO-85 (Cat ID 40967) is Back!
I totally agree that we have seen no DUV. I was really mainly looking at the 2 minute downlink with the "tail" at the start, but thank you for pointing out CAS-4a as looking very similar. The frequency is odd though.
As to the timing, I did not think that Celestrak had AO-85 since it launched with a classified satellite. In fact when I just looked it up, it said NEA, or "No Elements Available". SatNogs is getting elements from a different location.
In any case, thank you very much for taking the time to dig into this some more. It's probably worth it to keep looking. Maybe those batteries will open up sometime, and there may have been other cases where it has been see for all I know!
On Wed, May 4, 2022 at 12:45 PM Robert Meade rjm27trekkie@gmail.com wrote:
Burns,
I'm sorry to say that I don't believe AO-85 is showing any signs of recovery per my observations or what you've shown via the satnogs network. I looked through a number of other observations on the network and have not seen DUV telemetry from AO-85, which would have a much smaller BW than the telemetry pictured in the linked observation and look overall different. The pictured waterfall in the observation you linked is instead characteristic of GMSK telemetry from CAS-4A; you can even see the CW beacon for CAS-4A sitting above CAS-4A's 2 min reboot cycling telemetry link. See: https://link.edgepilot.com/s/aa7c2f63/NEk7QLulCU_tUVgeISk1Iw?u=https://imgur...
Zhuhai OVS-01 / CAS-4A (NORAD 42761) has been exhibiting this currently unique 2 min rebooting cycle behavior across many observations due to its loss of stabilization and now negative power budget (or so is current prevailing speculation by CAMSAT). I have made many observations of this phenomenon over the past few weeks for CAS-4A that you can see here: https://link.edgepilot.com/s/c6f84a65/CLo0TIOGmkOPoRwyTCjyTw?u=https://netwo...
Additionally, the most recent TLE from celestrak (space-track mirrored) I have for AO-85 (today) doesn't even have AO-85 over the observing satnogs station when the linked observation was captured when I backpropagate things by a week in GPredict, although I will grant you that CAS-4A doesn't downlink on a frequency near what should have been observed for the FOX-1A pass by 2220 - Mogielnica - VHF https://link.edgepilot.com/s/0b8edae6/hbTrVrwFYUanAIs794PqHg?u=https://network.satnogs.org/stations/2220/ in KN09wx. I believe the satnogs station you linked was malfunctioning in some way, since no FOX - 1A observation should have been scheduled at that time for that observer as AO-85 wasn't there. The frequency difference could probably be explained by overloading the LNA used or other aliasing, or it could just be reported wrong by the satnogs station client. It is probably also worth noting that the TLE used came from Cal-Poly, which is an atypical source... So maybe that is part of the confusion and or issues with 2220.
My personal theory is that the client observed CAS-4A with the wrong doppler curve and reported its obs for AO-85.
-Robert, KB3WFQ
PS: FYI this is what DUV-200 TLM looks like https://link.edgepilot.com/s/bdefe842/0iirVRsouUSAOdMFNVrHPg?u=https://netwo...
On Wed, May 4, 2022 at 11:07 AM Burns Fisher wb1fj-bb@fisher.cc wrote:
Certainly worth having more eyes on it, Robert. Here is the observation that I know of: https://link.edgepilot.com/s/261b5944/xP0T4LP3JkyBwqmtdLbDnw?u=https://netwo...
The suspect is the wide signal in the middle which is not absolutely perfectly doppler corrected, but the key to think it is AO-85 is the little "tail" when it turns on. That is very much like the Fox FM satellite behavior. If you listen to the audio, it sounds like the tx and rx are on with no uplink signal. Very similar to what Fox FM satellites sound like when they time out.
The other signal in that observation (higher frequency, more doppler, two frequency side-by-side) I have seen commonly on AO-85 observations and on my own rig. I expect that is another bird in a similar orbit. But I've only seen that wide signal once.
On Wed, May 4, 2022 at 10:59 AM Robert Meade rjm27trekkie@gmail.com wrote:
If we are citing satnogs as the point of origin for evidence of the renewed operating condition of AO-85, can we link to the observations where it was found working? Are we sure these weren't overlapping passes with other birds? Did the doppler correction match precisely to support it not being an overlap?
-Robert, KB3WFQ
On Wed, May 4, 2022 at 10:40 AM Burns Fisher wb1fj-bb@fisher.cc wrote:
Thank you for posting AO-85 again Ray.
Folks, I've seen a single pass of AO-85 on SatNogs that looked like the repeater was running. Purely from looking at the waterfall, I did not see any telemetry data, and it appeared that the repeater was on for roughly two minutes, then cut off briefly, and then restarted. I saw no obvious signals being repeated.
I also tried a pass or 2 from my QTH and did not see or hear 85 (although there are other things at a similar time whose dopplers were not matching). So don't get your hopes up too high, but please do report anything. Especially try FoxTelem to see if you get data, and try uplinks to see if you can hear yourself (or anyone else). Be sure to report it in https://link.edgepilot.com/s/c12abdff/qI0g8Kos3kaGWmFFetsing?u=https://www.a... as well as here and/or the AMSAT Discord board.
Thanks!
Burns Fisher
AMSAT Flight Software
On Tue, May 3, 2022 at 10:49 PM ray.hoad@mypbmail.com wrote:
AO-85 is back!!! Per Paul Stoetzer, N8HM "it seems to have woken up." Like AO-07, you just can't keep a good satellite down.
TLE for AO-85 will be included in this week's TLE distribution.
For now, here are current TLE for AO-85:
AO-85 1 40967U 15058D 22122.55538421 .00005037 00000-0 52331-3 0 3555 2 40967 64.7745 211.7318 0200720 214.8082 143.9700 14.77257778 53883
Ray Hoad WA5QGD AMSAT-NA Orbital Elements Manager
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