Long Overdue Update
By Roger J A Duthie, on 4 April 2012
Apologies for the long delay in posts to this blog. We have had a good numbre of people asking about the status of the project, and it’s about time we fessed up to what we’re doing this end.
Firstly, not a lot in relation to the Prospero recontact attempt. Though we haven’t given up. Our day jobs have been making pressing demands on our time and the Prospero project has been sidelined as a result. We’ve not been comeplete neglecting it, however.
Our custom electronics now has a custom metal box. Previously the circuitry was housed in a cardboard box wrapped in tin foil (very space-age, indeed). Also, we’ve been tackling the problem of the cross-talk we pick up on the Fun Cube Dongle (FCD). The idea of having a filter about the desired (Prospero downlink) frequency on the input wsan’t sufficient. The filter in this case allowed too wide a band and the cross-talk was still apparent in the signal. The new strategy is then to down-shift the frquencies in the signal received, filter it with a robust low-frequency pass-filtere, then up-shift the frequencies before passing it to the FCD. This is still in progress.
So, again apologies for the radio silence – we hope to have the filter set up when we have time and have another go at contact soon after.
Also, there was an article in BBC Focus magazine about the Ariel series of satellites where myself (Roger Duthie) was interview by the journalist about our commanding attempt.
It was promised that a copy would be sent to us, though it didn’t appear. Perhaps the interview wasn’t used, though the content on Ariel would have been interesting all the same.
You got 2/3 of a page in current Focus magazine incl pics. Your kit looks similar vintage to Prospero! Your blog is bound to see plenty traffic, you should try and get some more info up, help & funding will surely follow. Anyway, good on you, it’s inspiring to read your attempts
Just wondered what frequency to listen on? THe Space Staion bangs in loud and clear here, but as you’ll appreciate only a few mins at a time!
25-May-12 1648 UTC
Just for a lark, I tuned my FT-817 to 137.560 and listened on my 9el 2m yagi, horizontally polarised, beaming east from Sheffield.
Expecting to hear only noise, I was astonished to hear a regular sort of chuff-chuff sound which faded away in some minutes. I was so startled at hearing something at the first attempt that I completely failed to record it.
Prospero? Might it still be sending out a beacon?
Does this sound like Prospero? It’s much stronger than I thought it would be.
Or maybe an Orbcomm?
http://www.youtube.com/watch?v=xaDvopGE2PY
We think this is Orbcomm or some groundbased source. It happens when Prospero is above the horizon or not. Another test would be to see which Orbcomm satellites are in proximity when this can be heard. From a source we found (http://www.svengrahn.pp.se/), Orbcomm A1-A8 are supposedly using the same downlink frequency of 137.560MHz.
How disappointing!
Yes, the signal persisted much longer than any nearby prospero pass might suggest. As well as being strong from time to time, the source moved around a lot over a period and I re-pointed the antenna to a variety of different directions to peak it up. So maybe the source is a satellite or more than one satellite? I failed to make sense of the pattern of directions.
To the ear, it sounded like the signal picked up in the Coast episode & identified by the engineer as Prospero’s sync clock, but he may have been mistaken?
Thanks for the link. I’ll check it out.
This looks a useful list of the satellites using 136-138 MHz:
http://www.zarya.info/Frequencies/Frequencies136.php
I have been doing a lot of experimentation with my FuncubeDongle. It is possible to optimise the settings to drastically reduce the “breakthrough” from POCSAG pagers.
Unfortunately one of the the frequencies these use is well within the 137MHz downlink band (137.975).
However that said, I have been able to tweak various of the FCD settings, and still achieve good sensitivity, to the extent I cant reduce my sig gen enough to loose the signal. Its a Racal synthesised sig gennie (9082) with a decent attenuator, I know to be accurate. Using a home built Quadrifilar Helicoidal I can hear loads of the above mentioned Orbcom stuff on 137.560 with minimal pager breakthrough.
I am playing with a dual helical notch filter, but this is proving very tricky to get working as the design states it should.
Strangely though, the most troublesome breakthrough does not come from the closest frequency (137.975) so if I can get the filter working correctly I will be able to increase the recieve gain somewhat. This filter design (re-tuned to 148MHz)should be able to completely eliminate breakthrough from the uplink TX.
Cheers for now.
Bob G8NSV
Hi, I’ve only just found this blog… fascinating stuff. I’ve have often wondered if Prospero was still functioning. I hope you manage to communicate with it, please keep us posted
Any news chaps?
Not really, sorry! We’re currently retooling our ground station for other purposes, so it’s uncertain whether we’ll ever give this a go again any time soon. There’s always the 50th anniversary… ;¬)
Hi all,
Firstly, great to see someones working on this!
I grew up on the Isle of Wight where the Black Knight engines were build and tested (Alum Bay).
I believe my grandad was also involved in Black Knight / Prospero through Saunders Roe – a sub-contractor at the time?
All the best with this – always a shame more cant be done on a national level, or that more of the general public would rather watch Big Brother… .
Good luck!