[HN Gopher] Carnarvon's NASA satellite dish receives first signa...
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Carnarvon's NASA satellite dish receives first signal in almost 40
years
Author : zdw
Score : 96 points
Date : 2025-01-13 04:09 UTC (1 days ago)
(HTM) web link (www.abc.net.au)
(TXT) w3m dump (www.abc.net.au)
| gradschool wrote:
| See [1] for a funny nostalgic Australian movie about it titled
| "The Dish".
|
| [1] https://www.imdb.com/title/tt0205873/
| wduquette wrote:
| Different antenna, though from the same era.
| dcminter wrote:
| Indeed, "The Dish" is about the Parkes0 radio telescope. Very
| fictional though :)
|
| Tom Scott did a nice video1 visiting it a little while back -
| as a vintage computing enthusiast I was rather pleased to see
| a PDP-11 in their equipment racks!
|
| 0 https://en.m.wikipedia.org/wiki/Parkes_Observatory
|
| 1 https://www.youtube.com/watch?v=6o38C-ultvw
| jagged-chisel wrote:
| I think the title would be more accurate to say "processed first
| signal in almost 40 years." I was wondering what this thing was
| listening to that hadn't transmitted in almost 40 years.
| emmelaich wrote:
| OTC is such a nostalgia name for many in Aus. The dish is here if
| you want a look:
| https://www.google.com/maps/place/OTC+Tracking+Station/@-24....
|
| It also reminded me that they released one of the first
| comprehensive open source C++ libraries way back It originally
| predated templates and Boost so I'd be very surprised if anyone
| uses it anymore.
|
| https://sourceforge.net/projects/ose/
|
| http://www.pennelynn.com/Documents/CUJ/HTML/14.04/PATAPIS/PA...
| botanical wrote:
| So there's a Carnarvon in Australia that has to do with radio
| telescopes and a Carnarvon in South Africa that has to do with
| radio telescopes? In South Africa, the Square Kilometre Array
| telescopes (and others) are situated within the Meerkat National
| Park outside of Carnarvon.
| blutack wrote:
| It's an anglicized version of a town in Wales:
|
| https://en.wikipedia.org/wiki/Caernarfon
| voidUpdate wrote:
| I was a little sad it wasn't that one, I'd have liked to go
| and see a radio telescope
| dcminter wrote:
| Jodrell Bank0 is open to visitors; not in Wales, but not a
| million miles away either.
|
| I remember reading something in The Hitch-hikers Guide to
| the Galaxy as a child and not just not knowing where
| "Jodrell Bank and Woomera" were, but not knowing what
| _manner of thing_ they were either :)
|
| 0 https://www.jodrellbank.net/
| ascorbic wrote:
| I've only been once, but I highly recommend Blue Dot
| Festival, which is a music and science festival held at
| Jodrell Bank. On the one hand it's a classic UK music
| festival, but alongside the usual stalls selling Peruvian
| hats and vegan wraps there are lots of stalls with grad
| students sharing cool stuff that they're working on. Like
| the best festivals it's good for kids but also good for
| all night drum and bass sessions.
| https://discoverthebluedot.com/
| erex78 wrote:
| Because they refurbished it and it's back up after 40 years (we
| didn't just suddenly communicate with extra terrestrials).
| Rooster61 wrote:
| Odd to hear the center waveguide referred to as the "optics" of
| the antenna. Having worked in that industry, I've never heard
| anyone refer to the RF paths/components as optics before. This
| type of antenna doesn't deal with the visible portion of the
| electromagnetic spectrum
| dhuk_2018 wrote:
| This goes back to the "olden days", we'd call them optics
| because there's a lens, an aperture, focus, waveguides, etc.
| Newer antennas actually DO have fiber optics (RF over fiber)
| conversion so you don't have to deal with waveguides and/or
| coaxial cables, just convert right to fiber at the feed.
| wildzzz wrote:
| There's still a wideband receiver at dish, right? Spectrum is
| being captured by an ADC and turned into an IQ packet stream
| over fiber networks, right?
| minetest2048 wrote:
| Its analog, the RF signal modulates the laser intensity and
| a photodiode recovers the signal
| MegaDeKay wrote:
| You still need to deal with waveguides in modern design. A
| system like this will have OMTs (OrthoMode Transducers) and
| couplers made from machined / electroformed components that
| are essentially waveguide. If it has transmit capability it
| will have some kind of Diplexer made in a similar fashion.
| And of course, if it has transmit capability, there will be
| some kind of waveguide between the feed and the High Power
| Amplifiers (either Klystrons or Travelling Wave Tube
| Amplifiers). There's always some waveguide to serve as
| plumbing between the feed, these components, and others like
| the LNAs (Low Noise Amplifiers).
|
| Most RF systems also won't convert right to fiber at the feed
| but have some kind of upconverter / downconverter assembly in
| the hub. Those converters might have fiber connectivity but
| more often than not it is some kind of intermediate IF
| frequency around the L/S-Band where the conversion to optical
| takes place separately.
|
| While I am rambling on, I think the applications of this
| antenna will be very limited. The frequencies in use are
| generally speaking much higher now than they were 40 years
| ago (they picked up NSS-12 at 4 GHz, which is more or less DC
| these days). At lower frequencies you can get away with a lot
| of slop with regard to RMS surface accuracy and the like, but
| the Ruze equation is a harsh mistress and gain suffers
| considerably as frequencies go up. Modern antennas designed
| to work at higher frequencies will have a much better overall
| stiffness and surface accuracy, so you have more gain at the
| same diameter vs an old beast like this. All this is probably
| moot because an antenna feed like this designed for low
| frequencies won't even pass high frequencies.
|
| The servo system is also another issue. They picked up a
| signal from a geostationary satellite which is as easy as it
| gets. If the satellite is inclined or (worse) in LEO / GEO,
| things get much tougher. And the higher the frequency, the
| tougher it gets because the antenna beamwidth is much tighter
| for a given diameter.
| dylan604 wrote:
| After watching the video, the biggest takeaway I got from it is
| that ABC News needs to invest in some portable lighting gear.
|
| A few weeks ago, there was a post about another radio dish being
| resurrected up in Denmark (maybe????). I love that these are
| being refurbished instead of just trying to build new ones.
| colechristensen wrote:
| I prefer less polished productions because in my experience
| there's a strong correlation between not being obsessive about
| appearances and having quality substance.
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