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

Thu Oct 27 08:17:17 PDT 2011

We're hearing these 'chuff-chuff swooshes' too, though at times when our 
software is not showing Orbcomm over our horizon.  Our TLEs may be 
slightly out-of-date, though I think it would be a marginal thing.  Can 
it be definitely confirmed that these noises are Orbcomm?

- Rr.

Tony Abbey wrote:
> 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 
>> <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
>>
>> w: +44(0)1483 204 100 ext 2299
>> m: +44(0)7938 55 70 44
>>     
>

-- 
---
Roger J A Duthie
PhD Candidate
Plasma Group
Department of Space & Climate Physics
UCL, London

w: +44(0)1483 204 100 ext 2299
m: +44(0)7938 55 70 44