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

[Tony Abbey]

Hi  Jan


Yes - that's exactly the sound I have been receiving. I tried putting in the TLE for an Orbcomm sat when Graham told me about them, and the doppler correction seemed to match.


Tony Abbey (G3OVH) - 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 12:52, 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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> 
> 
> -- 
> With regards Jan H. van Gils
> Internet web-page http://www.VGNet.NL/
> Internet e-mail address JanVG[at]VGNet.NL
> 
> 
>