[amsat-bb] AO-85 "reset" during pass

[Burns Fisher]

Thanks Jerry.  I never remember that timeout period even though I'm
the one that typed it into the software :-)

On Sun, Nov 8, 2015 at 2:55 PM, Jerry Buxton <n0jy at amsat.org> wrote:
> A few thoughts on this.
>
> First, Burns mentioned "the hang timer on the transponder timing out not
> having detected a 67Hz tone in a couple minutes".
> He mis-spoke accidentally, the timing is one minute not a couple of
> minutes.  So the hang timer will drop one minute after IHU ceases
> detecting a valid CTCSS.
>
> Regarding the CTCSS detection, with the receive sensitivity issue we
> believe that this couples with a "tight" tone detection that we
> implemented for power budget reasons that I will elaborate on after we
> commission AO-85.  The short story is that it makes it harder for AO-85
> to hear and therefore find the tone.  The tone detect requires the
> presence of the tone for 1.5-2 seconds to consider it valid therefore
> any fading, loss of signal, a stronger station capturing the receiver
> and perhaps being off frequency or low elevation so that their tone was
> not heard to continue that two seconds, or perhaps the strongest station
> was not using a tone - a number of factors might make it such that IHU
> just didn't hear a tone that it considers valid, for 60 seconds, so the
> hang timer times out.  The tone is detected again, the hang timer is
> activated.
>
> The description of the situation indicates the lack of tone detect and
> hang timer timeout based my experience testing Fox-1A.
>
> Yes, tone detect is being addressed in Fox-1Cliff/D/B.    :-)
>
> Thanks for the reports.  Hopefully this will help you understand what is
> probably happening, so that you might recognize it if it happens again
> and more importantly recognize if it is NOT what happened in a future
> situation that you report to us.
>
> Jerry Buxton, NØJY
>
> On 11/8/2015 12:43, Daniel Estévez wrote:
>> I'm a bit doubtful on the no 67Hz on input theory. There were several
>> stations trying to hit the satellite, including me. I was using only 5W,
>> so perhaps the satellite won't lock to my 67Hz tone except in good
>> conditions, but the other stations were probably using more power.
>>
>> El 08/11/15 a las 18:19, David G0MRF escribió:
>>> I think that just means there was no 67Hz on the input to start the 1
>>> minute timer.
>>>
>>> However, there were some mails about testing another mode yesterday, so
>>> the answer may be there.
>>>
>>> 73
>>>
>>> David
>>>
>>>
>>> -----Original Message-----
>>> From: Daniel Estévez <daniel at destevez.net>
>>> To: amsat-bb <amsat-bb at amsat.org>
>>> Sent: Sun, 8 Nov 2015 14:37
>>> Subject: [amsat-bb] AO-85 "reset" during pass
>>>
>>> Hi all, An unusual thing happened during AO-85 last pass over Europe, at
>>> about 14:20 UTC or so. The transponder stopped working and the satellite
>>> went silent for about a minute. Then came the voice announcement in the
>>> lines of "Hi! This is radio amateur satellite Fox 1", and some seconds
>>> later the transponder started working again. I'm sorry that I have no
>>> telemetry recording of the pass to try to see what happened. 73, Dani
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