One of the more popular activities in the ham radio world is DXing, which is attempting to communicate with radio stations as far away as possible. There are some feats that will earn some major credibility in this arena, like two-way communication with Antarctica with only a few watts of power, long-path communication around the globe, or even bouncing a signal off the moon and back to a faraway point on Earth. But these modes all have one thing in common: they’re communicating with someone who’s also presumably on the same planet. Barring extraterrestrial contact, if you want to step up your DX game you’ll want to try to contact some of our deep-space probes (PDF warning).
[David Prutchi] aka [N2QG] has been doing this for a number of years now and has a wealth of knowledge and experience to share. He’s using both a 3.2 meter dish and a 1.2 meter dish for probing deep space, as well as some custom feed horns and other antennas to mount to them. Generally these signals are incredibly small since they travel a long way through deep space, so some amplification of the received signals is also needed. Not only that, but since planets and satellites are all moving with respect to each other, some sort of tracking system is needed to actively point the dish in the correct direction.
With all of that taken care of, it’s time to see what sort of signals are coming in. Compared to NASA’s 70-meter antennas used to communicate with deep space, some signals received on smaller dishes like these will only see the carrier wave. This was the case when an amateur radio group used an old radio telescope to detect one of the Voyager signals recently. But there are a few cases where [David] was able to actually receive data and demodulate it, so it’s not always carrier-only. If you’re sitting on an old satellite TV dish like these, we’d certainly recommend pointing it to the sky to see what’s out there. If not, you can always 3D print one.
PDF link is dead
You can download directly from my web page:
https://www.prutchi.com/wp-content/uploads/2023/11/Amateur_DSN_Prutchi_2023.pdf
I’m loving the turn towards ham radio and DX recently!
MBM is a bucket list goal (actually for distance rather than DX).
Pdf link works fine here, very impressive presentation.
PDF link works fine here, very impressive presentation. Thanks for sharing.
Still chasing the Elser-Mathes Cup, though.
One thing I’ve wondered about… what kind of authentication do spacecraft use, especially the older ones? One of the side effects of new technology making it easier to receive signals from distant spacecraft is that it’s also easier to transmit signals to them. How difficult would it be for some idiot to permanently brick Voyager 1, for example?
Interesting question. Initially I thought the equipment needed would be prohibitive and remove the need. But on reflection, a lot of these were built during the cold war/space race, so someone would have been thinking “hey it would be bad if the Russians could turn off our satellites”
I assume that satellites from the 60s or 70s were mostly still analog.
Signals were encoded analog in FM channels and/or by using other modulation schemes.
Time based multiplexing and other tricks had been used, too.
So on/offseitching probably was done using a sequence of pulses or by using a dedicated control receiver on a different radio band.
Also, many satellites were still analog linear transponders of some sort.
Like Oscar 7, which is also from 70s, but was quite advanced for its time (had TTL circuits and RTTY+morse beacon).
This thinking is typical for our time and a testament of the state of our civilation.
I think that a) back then no one else except nations had the technology to communicate on an interstellar distance and b) that no one in his/her sane mind had the intention to sabotage a peaceful, civil research probe.
That negative, criminal energy simply wasn’t there. Not even among nations. Science had been respected, still.
Also, even if there are no “passwords” or encryption, there had been control commands that only mission control had used on the transmitting side. So unless someone had a spacecraft in orbit monitoring the signals of the big satellite dishes, there was little chance to monitor the control commands. Here on earth, at least, it was very hard to do, because high frequencies don’t bounce back to earth. They’re not being reflected by atmosphere like shortwave signals are.
Having a security mindset isn’t some lamentable thing. People back then should’ve locked their cars and front doors, too.
In the US, maybe, yes. In my country or city, it used to be normal not to do it.
In hot summer nights, half the street had opened their doors and windows.
And none were robbed. People knew to behave, they had basic manners.
Likewise, there was a time when adult strangers took care of children in the public.
If they had an accident or got lost, they provided help as if it were their own children.
Sure there were exceptions to both of this, as usual, but they were statistically low.
“Having a security mindset isn’t some lamentable thing. ”
Right. It’s rather about dirty and harmful thoughts, I think.
It’s like having phantasies about cruelsome deaths and imagining how others could expire horrible pains.
Not all people are like this, however. Or rather, not all people were like this, however.
The current zeitgeist is very negative, very hopeless, very pessimistic and cynical.
Bad behavior is being stilized as if it was normal and most human thing.
I mean, just look at what S-Trek has become. The 90s was about a bright future, people were full of optimism.
Back then it didn’t cross the people’s mind to sabotage a harmless space probe, for example.
(Or to build a fake time signal station as a “prank” – a very bad idea with possibly very bad consequences!)
Those who theorethically had the technology to do so and mastered its use were simultanously so mentally advanced, so civil, that they had understood and admired the project.
The last thing they would have had done was destroying it.
Or let’s take the 1960s and 70s.
People all around the globe had prayed for the astronauts of Apollo 13.
They saw lost humans in space, not just Americans.
The people behind iron curtain were as worried as anyone else, for example.
Or let me put it this way, if the Apollo-Soyuz mission had happened in our current time, then the astronauts wouldn’t shake hands and symbolize peace and brothership but blast the other vehicle into dust by using a bazooka. And their citizens on earth would applaud.
That’s what society/civilisation had become in the past years.
Some random idiot most likely doesn’t have access to a 70 meter dish and a huge S band transmitter that is required to send a signal to the Voyager probes.
Forget the antennas, I want the house! Nisssshhhhe!
Most hams have received signals from at least 93 million miles away.
You can pretty easily receive signals from Jupiter, look up Jovian radio emissions, little bit further than 93 million miles
Yes, I’m actually a subscriber to the Radio Jove email list. I was using a 5 element wire log periodic antenna that I designed and built, pointed upwards at 70 degrees, but thus far haven’t conclusively received signals from Jupiter. I haven’t been active on it lately, though, and as best I can tell the reception appears to be somewhat seasonal so maybe that’s why.
And hydrogen line reception is even further yet and not too difficult with gear costing less than $150.
You can watch cosmic background noise on your analog TV..
I was transported to adventure movies from the 1930’s and 40’s. “Carrier Wave”.
Very cool stuff. Although. Traditionally a contact is defined as two way communication. Unless you are hi jacking voyager it is not really two way.
The naked eye detects electromagnetic emissions from every star in the sky. That’s some low tech one way reception with no special equipment hahah
Yesterday, Dwingeloo and an amateur in Switzerland were the first ever to bounce an amateur radio signal off a geostationary satellite: https://www.camras.nl/blog/2025/eerste-verbinding-via-geostationaire-satelliet/
Oops, I missed the earlier article on that…. https://hackaday.com/2025/01/24/bouncing-signals-off-of-satellites-other-than-the-moon/
The colder, the better
https://phys.org/news/2025-01-malarge-satellite-dish-cold-cryogenic.html
https://www.reddit.com/r/megalophobia/comments/1g2557n/the_kalyazin_rt64_radio_telescope_in_russia_built/
https://www.tiktok.com/@pearlofskills/video/7454913258084994346