alt.hn

1/13/2025 at 4:09:24 AM

Carnarvon's NASA satellite dish receives first signal in almost 40 years

 https://www.abc.net.au/news/2024-12-03/carnarvon-nasa-dish-receives-signal-repairs/104672866

by zdw

1/14/2025 at 1:59:38 PM

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...

by emmelaich

1/15/2025 at 7:09:59 PM

> "...I'd be very surprised if anyone uses it anymore."

We actually still use OSE on my team believe it or not. The project started in 1997, so OSE was a great choice for container structures / string handling / etc.

We are re-factoring OSE usages to use standard library features as we go along. But the project is huge with a very small team; hence why we still use it.

by Bearstrike

1/14/2025 at 1:03:41 PM

See [1] for a funny nostalgic Australian movie about it titled "The Dish".

[1] https://www.imdb.com/title/tt0205873/

by gradschool

1/14/2025 at 2:25:35 PM

Because they refurbished it and it’s back up after 40 years (we didn’t just suddenly communicate with extra terrestrials).

by erex78

1/14/2025 at 1:55:22 PM

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.

by jagged-chisel

1/14/2025 at 2:01:30 PM

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.

by botanical

1/14/2025 at 2:13:34 PM

It's an anglicized version of a town in Wales:

https://en.wikipedia.org/wiki/Caernarfon

by blutack

1/14/2025 at 2:27:41 PM

I was a little sad it wasn't that one, I'd have liked to go and see a radio telescope

by voidUpdate

1/14/2025 at 5:18:47 PM

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/

by dcminter

1/14/2025 at 8:48:53 PM

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/

by ascorbic

1/15/2025 at 8:26:05 AM

Oh, I thought that one was in australia too haha, thats a lot closer to me

by voidUpdate

1/14/2025 at 5:02:25 PM

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.

by dylan604

1/14/2025 at 5:17:40 PM

I prefer less polished productions because in my experience there’s a strong correlation between not being obsessive about appearances and having quality substance.

by colechristensen

1/15/2025 at 7:28:40 AM

Canarvon is over a 9 hour drive from Perth, and the ABC in the regions is on a shoestring budget as our conservatives think it better to give newstainment talking heads money when compared to actually funding the state backed news broadcaster.

by plugger

1/14/2025 at 2:45:29 PM

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

by Rooster61

1/14/2025 at 2:50:45 PM

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.

by dhuk_2018

1/14/2025 at 8:14:54 PM

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.

by MegaDeKay

1/14/2025 at 4:30:08 PM

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?

by wildzzz

1/14/2025 at 7:17:03 PM

Its analog, the RF signal modulates the laser intensity and a photodiode recovers the signal

by minetest2048

1/15/2025 at 2:38:59 PM

Interesting. I never considered that.

by wildzzz