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

Fri Oct 28 02:39:19 PDT 2011

Hi Roger,

All understood..I have put the currently 28? active Orbcomms into Nova here and almost all of the time there is at least one  above my horizon and I can hear the chuffing noises..will be listening again this evening

Do you have details of the on board power system?  For instance what are the batteries? If the batteries have failed short circuit will they be clamping the bus to 0volts? Can the power system work with open circuit cells? What is/was the default power up operating mode?  

good luck!

Graham
G3VZV

From: Roger Duthie 
Sent: Friday, October 28, 2011 10:25 AM
To: Tony Abbey 
Cc: pe0sat at vgnet.nl ; g.shirville at btinternet.com ; Phil Guttridge ; amsat-bb at amsat.org ; g8nsv at ntlworld.com ; Dale Potts ; Barry Hancock ; Richard Cole ; mailto:rac at mssl.ucl.ac.uk ; Alan Smith ; Graham Kimbell (G3TCT) 
Subject: Re: [amsat-bb] Re: [Re: Prospero] Commanding Error

OK - so that's definitely Orbcomm (from the spectrogram).  Have you got audio of this?  

We hear a chuffing sound intermittently (ie., it comes and goes in interval of minutes), which happens when neither Orbcomm nor Prospero is reported by our software to be above the horizon (is this the pager stuff you're talking about?).  We also heard another thing a couple of days ago, though we're still not 100% on what that might have been (it appeared to be fading as Prospero receded to the North - though was it an aeroplane on 137.56?).

Someone yesterday has supposedly heard something that's wasn't Orbcomm during the early evening pass.  We'll look into it.

The pass we're going to try today (for the sake of ceremony, really) is (again, times in BST = UT + 1):

      28 Oct 7.4 15:53:18 10 S  16:00:22 86 W  16:08:28 10 N  

- Roger
m0rja

Tony Abbey wrote: 
  Hi Roger 

  Once Graham told me the noise was Orbcomm this morning, I added the TLEs for their satellites (http://www.orbcomm.com/Collateral/Documents/English-US/o11292.tle)
  to my SDR Radio software satellite definitions. Here's a pass I recorded from one of them this morning, and you can see that the "chuff-chuff" on the left hand side has structure which is kept vertical by the doppler correction. The other crap and pager cross talk etc bends with the doppler correction. I think that proves the point.

  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

------------------------------------------------------------------------------
  Spectrogram removed by RJAD (might ahve been bad for the amsat-bb board)

------------------------------------------------------------------------------

  On 27 Oct 2011, at 16:17, Roger Duthie wrote:

    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 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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