X Band frequency

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hoi.polloi
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X Band frequency

Unread post by hoi.polloi »

I was just looking up smaller space programs for signs of ineptitude and discovered this awesomely fishy "X Band".

According to wiki:
The X band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of the X band is rather indefinitely set at approximately 7.0 to 11.2 GHz[citation needed]. In radar engineering, the frequency range is specified by the IEEE at 8.0 to 12.0 GHz. The X band is used for radar, satellite communication, and wireless computer networks.
So "rather indefinitely set at approximately" ... means there is no way for the military to monitor every single instance of "X Band" right?

Hey, it's just a frequency. So why is it being called an "X" band X actly? Let's see what interesting projects are said to claim use of this relatively rather indefinitely large range of frequencies.
Portions of the X band are assigned by the International Telecommunications Union (ITU) exclusively for deep space telecommunications.
Aha, so there we have familiar mentioning of the ITU which manages all the official "satellite positions".
The primary user of this allocation is the American NASA Deep Space Network (DSN)[citation needed]. DSN facilities are located in Goldstone, California (in the Mojave Desert), near Canberra, Australia, and near Madrid, Spain.
"Primary user" I'd say definitely needs some citation on that. Well, we can count on Wikipedia to provide that eventually. The important point is that it confirms the psy-ence priesthood's beliefs for now; we'll get around to proving their miracles later.
These three stations, located approximately 120 degrees apart in longitude, provide continual communications from the Earth to almost any point in the Solar System independent of Earth rotation. DSN stations are capable of using the older and lower S band deep-space radio communications allocations, and some higher frequencies on a more-or-less experimental basis, such as in the K band.
Note that officially, the low end of the K band is for NASA use with "satellite communications" (Ha ha) and the high end of the K band is also used by NASA for "experimental" space communications. Yet the K band in between (officially 18–27 GHz) is described: "Due to the 22 GHz water vapor absorption line this band has high atmospheric attenuation and is only useful for short range applications." - Wikipedia.

Back to our more "manageable" X band:
deep space probe programs that have employed X band communications include the Viking Mars landers; the Voyager missions to Jupiter, Saturn, and beyond; the Galileo Jupiter orbiter; the New Horizons mission to Pluto and the Kuiper belt, the Curiosity rover and the Cassini-Huygens Saturn orbiter.

The new European double Mars Mission ExoMars will also use X band communication, on the instrument LaRa, to study the internal structure of Mars, and to make precise measurements of the rotation and orientation of Mars by monitoring two-way Doppler frequency shifts between the surface platform and Earth. It will also detect variations in angular momentum due to the redistribution of masses, such as the migration of ice from the polar caps to the atmosphere.
So if it eventually develops that the "X band" mechanisms are not actually reliable outside of Earth's atmosphere due to other electromagnetic disturbances, then all these tales being claimed "true" would present a problem, yes? Well, no matter. If we haven't actually sent instruments there, we just wouldn't know, would we? Just a little thought. Forgive me for exercising my wild imagination.
An important use of the X band communications came with the two Viking program landers. When the planet Mars was passing near or behind the Sun, as seen from the Earth, a Viking lander would transmit two simultaneous continuous-wave carriers, one in the S band and one in the X band in the direction of the Earth, where they were picked up by DSN ground stations.
Small interjection: "The S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the conventional boundary between the UHF and SHF bands at 3.0 GHz. The S band is used by weather radar, surface ship radar, and some communications satellites, especially those used by NASA to communicate with the Space Shuttle and the International Space Station." - Wikipedia

Hmm. Well, anyway...
By making simultaneous measurements at the two different frequencies, the resulting data enabled theoretical physicists to verify the mathematical predictions of Albert Einstein's General Theory of Relativity. These results are some of the best confirmations of the General Theory of Relativity.
-https://en.wikipedia.org/wiki/X_band
-https://en.wikipedia.org/wiki/K_band_(IEEE)
-https://en.wikipedia.org/wiki/S_band

In what way is this militarily controlled frequency excellent proof of Einstein's ridiculous ideas? This seems not only rather "left field" but completely stubby considering the suggestion is that X band's alleged obscurity in regards to "proving General Relativity" is not worth mentioning after its ostensible historical importance is dropped in clumsily.

And how many space missions are playing around in "S Band" "X Band" or "K Band" in the microwave range from 2 Ghz to 40 Ghz?

Something tells me that since the military heavily monitors, controls, dishes out, takes away and otherwise designates our bandwidth they are also at liberty to tell us what signals are doing without us being the wiser.

We can certainly pick up and test X band given the right calibrated equipment, I am sure.

But what can we do to measure the distance the signals are traveling? Are they really coming from space (seems unlikely) or merely bouncing or sending from high altitude amplifiers and antennae? A weakness in their claim is the fact that average folks like us have no easy means of knowing the distance a signal has traveled, even if we tried to estimate it based on the dilution of the signal. So once more, we must simply take it "on faith" that they know what they are talking about, the signals travel "in space" and "broadcast by special instruments" just as far and intact as terrestrial generated or cosmically generated versions of such.

Do we have any evidence at all that signals in the "X Band" are particularly right for "space missions"?
bongostaple
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Joined: Tue Oct 04, 2016 11:53 am

Re: X Band frequency

Unread post by bongostaple »

Now you're talking. It's been on my list for over two years due to being hideously busy in all aspects of my life, but I started looking into exactly what I can pick up in the K and X Bands. Information is very sparse, but I gather the US had some kind of floating dome test rig that was supposedly for X-band evaluation. This was a couple of years ago at least, but if they had huge experience in using it to communicate with satellites already, you'd think it wouldn't really be necessary.

I've got some specialised kit to bring stuff down from about 30MHz to low enough for a software-defined radio rig to pick up, so I need to put some time in and see what's floating around. Most of it would almost certainly be encrypted, but it ought to be possible to at least estimate the bandwidth that transmissions are operating at.

Fingers crossed, I will get some work done on that this next few months my original interest came from wanting to pick up GPS transmissions and work out if it's possible to spoof a satellite in space somewhere but in real life transmit the signal from a ground station. GPS currently allows for the use of ground stations, so it could be really simple - we'll see.
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