At the time of its construction in the 1950s, the Dwingeloo Radio Observatory was the largest rotatable telescope in the world with a dish diameter of 25 meters. It was quickly overtaken in the rankings but was used by astronomers for decades until it slowly fell into disuse in the early 2000s. After a restoration project the telescope is now a national heritage site in the Netherlands where it is also available for use by radio amateurs. Recently this group was able to receive signals from Voyager 1.
Famously, Voyager 1 is the furthest manmade object from Earth, having been launched on a trajectory out of the solar system in 1977. As a result of distance and age, the signals it sends out are incredibly faint. The team first had to mount a new antenna to the dish, which was not originally designed for signals in this frequency which added to the challenge. They then needed to use orbital predictions of the spacecraft in order to target the telescope and also make the correct adjustments to the received signal given that there is significant Doppler shift now as well. But with that all out of the way, the team was successfully able to receive the Voyager 1 signal on this telescope.
Only a few telescopes in the world have ever been able to accomplish this feat, making it all the more impressive. Normally Voyager 1 is received using the Deep Space Network, a fleet of much larger dishes stationed around the world and designed for these frequencies. But this team is used to taking on unique challenges. They also decoded the first ham radio station on the moon and made a radar image of the moon using LoRa.
I believe that Daniel Estevez has detected voyager 1 with only a 6 meter dish. See pages 53 and 54 of this document: https://www.pe0sat.vgnet.nl/download/DSN/David%20Prutchi%20-%20Receiving%20Microwave%20Signals%20from%20Deep-Space.pdf
But the Allen dish is DESIGNED for use at X Band and above. Dwingeloo’s surface accuracy or shape was never “good enough” above about 5GHz so its a mighty achievement. Shows what Amateurs can achieve by ignoring people saying ” Nah that’s impossible!”
Great job, Jan, Dick and the team.
I note that some of you had some success with moderate sized dishes designed for lower frequency bands ( ie not very good surface precision for high GHz bands).
If you can get hold of an Australian designed and built Andrew 4ft, superb-precision shape, 80% efficient, prime focus fed HACBSS dish (originally designed to receive satellite analogue TV at 12GHz, linear polarization) you will find that the antenna’s G/T performance matches/outperforms most readily available retail 2.4M – 3M dishes.
Several thousand high-precision 4ft HACBSS dishes were sold (quite cheaply) from about 1985 onwards.
Many can still be seen on Australian Pub and TAB rooftops.
Redundant, but still there.
🙏👍
Looks that I was forgotten from this document !!! ☹️
I did receive V1 some years ago and was actually a detection by 100% amateur means, not using any actual or former antenna from an institute or organization. You can check my web pages for the full story.
Cheers.
Luis Cupido /CT1DMK
That was a really nice achievement Luis, thanks for mentioning it here, I’ve read your website now.
Here’s a better link to his detection of the voyager: using a 6 meter dish https://destevez.net/2021/02/voyager-1-single-dish-detection-at-allen-telescope-array/
But is it repeatable and consistent long term. One shot for a while, cool. Wanna listen for a half revolution of the site, gonna need more gain to tolerate pointing error. 1/10 arc second error may mean you miss the signal
25 meter dish, 3.6 cm wavelength means the 3 dB beamwidth of the dish is 0.1 degrees, or ~360 arcseconds. Don’t think 0.1 arcsec is gonna do much.
There is the difference between detection and decoding, though. Decoding requires being able to detect the signal on a short enough timescale (160 bits/sec) with good enough SNR to separate the bits. This isn’t that.
True, but I was replying to the 6 meter dish. Bit tighter aperture
Smaller dish means wider beam.
Yup, beat me to it.
Characteristic beam width for a parabolic reflector is just wavelength over dish diameter, that’s it.
Hey, it’s a contact. With the most remote manmade radio source in existence. When you build something it doesn’t spawn fully-formed from your mind. Stuff like that would have to come after initial accomplishments and champagne.
I wonder if everybody can send a new firmware update to Voyager because the password is “nasa1958” and the error correction is sum of all bytes modulo 8. :-D
Olaf
I watched some space documentary and I’m pretty sure the key/PIN code is the same as I have on my luggage.
Is it “12345”?
:D
Yeah , but you’ll need some significant radiating power so It can hear you.
Carrier only, or are the observers able to decode some engineering data as well?
“They then needed to use orbital predictions of the spacecraft in order to target the telescope ‘ I doubt its position relative to the Sun is changing very quickly. From Earth you need a parallax correction since we swing by 2 AU or 1000 light seconds in 6 months. So maybe that should be orbital values for the Earth and apparent position of Voyager against the celestial sphere? It would be fun to find what rate it is moving against the background in Sun centered coordinates and the rates from Earth. And how far off the ecliptic is it.
I believe that they are just ‘detecting’ the carrier, not decoding the transmissions which you need a higher signal to noise ratio to do. Hey but that’s pretty cool to do anyways – you could always reprogram voyager to use a much slower method of transmission though and have the smaller dishes decode data. However strap 20 of the 6 meter dishes together and you are pretty close to decoding the current data stream: https://wfarah.github.io/blog/voyager1/
Whew I thought you meant with a homemade antenna at first, I was having trouble wrapping my head around that. Nice! Outside of E.T. this is literally the most impressive contact to make as a ham, regardless of what antenna you use
I get 40 arc minute change over a little less than 6 months if it isn’t moving.
Wow, there’s a whole 4db of SNR. Maybe about 1bps?
How do you go from 4 dB to 1bps?
Shannon-Hartley equation
Come on, it’s a transmitter from 1974 and a dish from 1950 at around 25 billion kilometers from here.
And the big old parabolic dish used by hams in Colorado
(No mention of them contacting V’ger)
https://dses.science/
In 2004, Tidbinbilla in ACT Australia was receiving 40 baud with a 2.5 db signal to noise ratio from a 70 metres dish. I was told that it would be 0 db sig/noise in 2025. How do you guys think you can detect it with less than a 70 metre dish? de VK5RE.
The Dwingeloo team can detect the carrier. They don’t have enough S/N to decode the signal.
You can see here:
https://destevez.net/2021/09/decoding-voyager-1/
what the full signal spectrum from Voyager actually looks like. The carrier is around 6 dB stronger than the data subcarriers, and you can see from the spectrum here that you’ve already lost any possibility of the subcarriers because they had to integrate significantly to even pick out the carrier (hence the narrow overall band).
Assuming integration is the reason for the cutoff, going from a ~10 kHz wide band to a ~50 kHz wide band would cost you all of the SNR on the carrier alone.
It was an impressive challenge to meet. Personally I’m happy to get a SSB signal a few thousand km on my battery powered portable ham station. But what a shame there won’t be a reception QSL card for this one!
That signal is strong enough to do FT8 ;)
Very nice and amazing. Great achievement. Thank you all
When I was at the University of Florida a colleague and I tracked the Apollo CSM to the moon. Just the carrier but still a thrill particularly when the CSM went behind the moon. Total LOS. And that was a neat validation to witness!
How cool! Do you ever document any of that? I and others I’m sure would really like to see what you did back then. It would be really great to have a record of what you did back then up on the web as detecting the carrier from Apollo out to the moon still counts as something awesome. There is an article in QST of June 1972 on page 60 where some hams actually received audio from Apollo 10, 12 , 14 and 15 all the way from the moon at the 2 Ghz frequency. There is another ham who picked up very brief audio from Apollo 11 from the surface of the moon on the 200 mhz frequency . And also another group at the University of Florida who monitored Apollo 17. Here’s the links to the above articles: https://www.worldradiohistory.com/Archive-DX/QST/60s/QST-1972-06.pdf
https://www.arrl.org/eavesdropping-on-apollo-11
http://www.svengrahn.pp.se/trackind/Apollo17/APOLLO17.htm
the Apollo 17 account is terrific. Thank you for sharing.
Glad you liked it, if you haven’t already, go check out the ‘CuriousMarc’ youtube channel where he and his friends manage to obtain and bring back to working order the Apollo communications system from most of the actual equipment left over from a very long time ago – it’s awesome! Here is the link to the last part (#34) so far: https://www.youtube.com/watch?v=2Jt0PsxLM7k&list=PL-_93BVApb58SXL-BCv4rVHL-8GuC2WGb&index=35
Amateurs received voyager1 signals at the Bochum dish many years ago. Which I recall being a 20mtr reflector.
But great to see another facility getting renovated.
That was in 2007, Voyager 1 has gained around 65 AU in distance since then. But really great that amateurs can achieve this kind of receptions.
WOW , what an accomplishment! Makes me want to return to the airwaves! Thanks! KB9GMI