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

[Roger Duthie]

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 
<http://www.heavens-above.com/Gtrack.aspx?Session=kebgfdallldcgimjaonedkpf&satid=5580&date=40843.617613831> 
	7.2 	15:42:26 	10 	S 	15:49:21 	77 	E 	15:57:21 	10 	NNE
27 Oct 
<http://www.heavens-above.com/Gtrack.aspx?Session=kebgfdallldcgimjaonedkpf&satid=5580&date=40843.6908054167> 
	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

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