Ham radio operators receive signals from Voyager 1 on Dwingeloo telescope
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> The telescope had three radar transmitters, with effective isotropic radiated powers (EIRPs) of 22 TW (continuous) at 2380 MHz
Twenty. Two. Terawatts. Now, what that means in context is that if you were looking down the business end of that dish, it would be hitting you with as much RF as though you were standing the same distance away from a 22 TW regular dipole antenna. Put another way, it shines with the same brightness at dead ahead as a 22 TW antenna would show from any direction perpendicular to its length. Because the dish is highly directional, it's only that bright in a tiny angle covering a tiny fraction of the sky.
If you're standing behind it, nothing. In front of it? You turn into Dr. Manhattan.
It's amazing.
link that works on generic ytube clients like newpipe
Is there actually no back lobe on dishes that size? Or is it just extremely small?
We looked at the sun and some planets in radio frequencies (its all radio astronomy with LOFAR nearby).
That they can listen to Voyager with such an old instrument is incredible. It must help that the satellite is aimed at us.
It is indeed incredible.
Nitpick, but I'm not sure 'satellite' is correct in this context. Voyager is in a solar system escape trajectory.
Arecibo failed to do so.
Decommissioned Announced November 19, 2020 Collapsed December 1, 2020
[1]: https://en.wikipedia.org/wiki/Dwingeloo_Radio_Observatory
It's cool that they kept it operational for amateurs and education.
I went there again with my own kids a couple of years ago and it was a bit disappointing. Not much to see. The solar system walk at the WSRT at Westerbork nearby is still cool.
Madrid Longitude: 4.3° W
Goldstone Longitude: 116.9° W
Canberra Longitude: 149.0° E
153.3° from Madrid to Canberra and only 94.1° from Canberra to Goldstone. Bit of a slight to Western Australia to skip over the ~120° option and put the third dish in Canberra.
They need to compensate the Doppler shift so that the signal stays in one bin over the 10s integration time. I imagine they are using non-coherent integration (basically computing total signal energy over 10s in each bin) to take into account that the doppler compensation is not perfect (if it was, you could have 0.1Hz bins with 10s integration time).
If the above is true, then yeah, they can't demodulate any data because the integration time is much longer than symbol duration.
I wonder if with more accurate Doppler prediction, you could get an ever longer integration time and narrower bins, and thus even bigger SNR gain, perhaps allowing signal detection with a smaller dish...
And that our solar system is more than a light day in diameter is also mind blowing.
Is there any info on this new antenna?
Over distance its about fighting the noise in between the source and the receiver while also fading because of the free space loss, think of a flashlight - not a laser. So nelly volume ticks down while the local stations ramp up..
To keep your car jamming you'd build a growing antenna attached to your ford festiva that as you made your way would compensate for this loss by collecting more signal to focus back to a feed horn, a parabolic - like a larger magnifying glass focusing more ant burning heat in the winter versus the summer.
Very roughly it seems it would be the size of Texas when you arrived at the BBQ, assuming you are traveling the speed of light and left in the early aughts.
You wouldn't hear the song until you hit the break because its the frequency over time that pumps the jam.
OK, but a giant parabolic dish is some parochial 20th century Earth tech.
I was imagining some little guys who create a 100 cubic AU grid of omnidirectional sensors, with a sensor every 1000km, all hooked up the mother of all DSPs. I can visualize that system identifying some pretty faint waves vibing in the noise. Am I wrong in thinking that this system could pickup AM radio really far away, easily... and once they got sick of that, even FM?
An AU cubic grid of detectors would inform you where a signal originates from by comparing free space loss over the area of the coverage. IF you could discern a station from static.
In my un-optimized imaginary system, the sensors are very sensitive and dumb, like me. All the difficult work is done by the central DSP-like brain that can identify even the tiniest of waves moving through the grid.
The utility comes from seeing the relative values in the grid... a pattern of tiny changes in some arc, moving through the grid.
Sure, killer triangulation (actually radial measurement?), but also possibly a decent 500 light-year AM tuner?
Imagine your array popped out SHORT-SHORT-SHORT-LONG-LONG-LONG-SHORT-SHORT-SHORT
You just heard a morse code for SOS! The shorts where detected over 100Mhz (FM) +30db for 1 second each and the longs were 3 seconds each on a carrier that sites at +10db. That's amplitude modulation and that looks like intelligence but unless you knew morse code - it wouldn't make any sense.
The further away you get from the source, the more those decibel spikes weaken and will eventually be no different than the noise floor. Your super computer with a billion ears, only hears ~static~.
Try this, imagine instead if there was no free space loss in the electromagnetic field - we'd wouldn't be hearing humming but SCREAMS from all the noise sources from EVERYWHERE as if we were right next to them, forever. It would impossible to decern anything from anywhere. Communication is defined by its distance because signals have differing origins. Sensitivity, or lack there in, is a feature not a failure.
Who's to say a quasar isn't just a lovely time clock for signals encoded in the noise and we haven't figured out what the breakpoint from noise is yet?
Apart from a) quasars are broad-spectrum, not narrow frequencies (at least I assume that is the case), and b) the power required is too large for a civilization to realistically be able to generate. Not to mention that all that power is overkill for intragalactic communication.
But it’s a good sci-fi idea!
Had to reread that a few times to make sure
https://en.wikipedia.org/wiki/List_of_forward_operating_base...
(I guess they preferred typing on DOS based systems even though windows 98 was mainstream by then since it meant you couldn't alt-tab and lose focus or cheat somehow? IDK know. Maybe it was a licensing issue)
I wonder if this was included as a "please don't ask us if we're capable of hacking it, we are not" CYA.
But it's still super easy to find them.
Usually it takes a few hours until the sat ham guys find them and post spectrums.
But today, Voyager 1 is a 50 year old curiosity, still of interest to cosmologists of course, but governments will be less interested in it than archeologists.
* e.g. https://voyager.gsfc.nasa.gov/Library/VOY_library.html and https://ntrs.nasa.gov/api/citations/19660011758/downloads/19...
Fully a third of the comments here are folks showing off their knowledge of non-acronyms.