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 http://www.heavens-above.com/Gtrack.aspx?Session=kebgfdallldcgimjaonedkpf&satid=5580&date=40844.6252559144 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 Our TLEs may be slightly out-of-date, though I think it would be a marginal thing.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 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@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@mssl.ucl.ac.uk Cc: Phil Guttridge ; amsat-bb@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 >>> _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb