[amsat-bb] Re: [Re: Prospero] Commanding Error

[Tony Abbey]

Nothing heard from Prospero here in Leicester, that pass just finished (at 14:57Z)
Just the Orbcomm swooshes.

Tony Abbey - Senior Research Fellow (retired)
Space Research Centre
Dept of Physics and Astronomy
University of Leicester
University Road 	SRC Web page: http://www.src.le.ac.uk 
LEICESTER LE1 7RH, United Kingdom





On 27 Oct 2011, at 13:33, Roger Duthie wrote:

> Well, we're hearing something like that.  Though we hear this a lot, we also wonder whether we''re seeing an envelope during the Prospero pass times.  
> 
> The passes for today (BST) [from Heavens-Above]:
> 27 Oct	7.2	15:42:26	10	S	15:49:21	77	E	15:57:21	10	NNE
> 27 Oct	8.7	17:28:31	10	WSW	17:34:45	31	WNW	17:41:39	10	N
> Also, I've started a Twitter hashtag for anyone using this mode of communication: #Prospero40  Add this to any Twitter messages you might write about Prospero or related subjects.
> 
> -Roger
> 
> PE0SAT wrote:
>> 
>> Hi,
>> 
>> I have a spectrogram and a recording of that "chuff chuff" on
>> http://www.pe0sat.vgnet.nl/satellite/sat-history/prospero/
>> 
>> Is it the same you guys heard?
>> 
>> 73 Jan PE0SAT
>> 
>> 
>> On Thu, October 27, 2011 10:04, g.shirville at btinternet.com wrote:
>>   
>>> Hi Tony,
>>> 
>>> The chuff chuff noises are from space...they are a sort of beacon carried
>>> on
>>> every Orbcomm satellite. They are 125msec long pulses of 57.6kb data and
>>> have a bandwidth of around 50kHz. They are quite distinctive when you only
>>> hear one at a time but sometimes one can hear two or more signals at the
>>> same time and that sort of changes the sound:)
>>> 
>>> 73
>>> 
>>> Graham
>>> G3VZV
>>> 
>>> -----Original Message-----
>>> From: Tony Abbey
>>> Sent: Wednesday, October 26, 2011 8:56 PM
>>> To: rjad at mssl.ucl.ac.uk
>>> Cc: Phil Guttridge ; amsat-bb at amsat.org
>>> Subject: [amsat-bb] Re: [Re: Prospero] Commanding Error
>>> 
>>> Hi Roger
>>> 
>>> Nothing other than the chuff- chuff on the 1600 pass. And as you said, its
>>> also there with Prospero over the horizon. I 'm not using a beam presently
>>> -
>>> using a 360deg parasitic Lindenblad for circular polarisation, but it is
>>> susceptible to all the high power pager stuff nearby. Its just strange
>>> that
>>> there are elements shifting in frequency in the chuff chuff like a signal
>>> from a real satellite.
>>> Have just come back from a Rosat re-entry celebration!
>>> 
>>> Tony Abbey - Senior Research Fellow (retired)
>>> Space Research Centre
>>> Dept of Physics and Astronomy
>>> University of Leicester
>>> University Road SRC Web page: http://www.src.le.ac.uk
>>> LEICESTER LE1 7RH, United Kingdom
>>> 
>>> 
>>> 
>>> 
>>> 
>>> On 26 Oct 2011, at 16:17, Roger Duthie wrote:
>>> 
>>>     
>>>> Tony -
>>>> 
>>>> We heard something intriguing after about 14:43:40 UT as the tracking
>>>> said
>>>> the satellite was on it's way off to the north pole.
>>>> 
>>>> The 'chuff-chuff' description reminds me of a sound we seem to hear
>>>> quite
>>>> a lot.  Quite often it coincides with a pass, though I think we hear the
>>>> same (or very similar) during times when Prospero is over the horizon.
>>>> 
>>>> We are going to try the next pass at ~16:00UT if you want to listen in
>>>> again.  Our new ploy is to wait for the last most opportune moment to
>>>> command, as the power _may_ be at it highest (longest charging of
>>>> batteries, potentially).  So, we'll do short commanding at above 30o el,
>>>> and listen.
>>>> 
>>>> -Rr.
>>>> 
>>>> Tony Abbey wrote:
>>>>       
>>>>> Hi Roger
>>>>> 
>>>>> I could hear some "chuff-chuff" noises on the last pass and they show a
>>>>> related doppler shift (although I am not correcting sufficiently) as
>>>>> you
>>>>> can see in the attached plot. Maybe its some other noise but you never
>>>>> know.
>>>>> 
>>>>> On 26 Oct 2011, at 13:39, Roger Duthie wrote:
>>>>>         
>>>>>> Commanding went well, from as far as we could make out.  We're not
>>>>>> sure
>>>>>> if we're getting anything back, however.
>>>>>> 
>>>>>> We'll be doing this pass today, hopefully:
>>>>>> 
>>>>>> 26 Oct 7.3 15:31:43 10 S 15:38:26 60 E 15:46:11 10 NNE [Times in BST =
>>>>>> UTC + 1]
>>>>>> 
>>>>>> -Roger
>>>>>>           
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>>> _______________________________________________
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>>>     
>> 
>> 
>>   
> 
> -- 
> ---
> Roger J A Duthie
> PhD Candidate
> Plasma Group
> Department of Space & Climate Physics
> UCL, London
> 
> w: +44(0)1483 204 100 ext 2299
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