Satellites : general discussion and musings

If NASA faked the moon landings, does the agency have any credibility at all? Was the Space Shuttle program also a hoax? Is the International Space Station another one? Do not dismiss these hypotheses offhand. Check out our wider NASA research and make up your own mind about it all.
Libero
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Re: Satellites : general discussion and musings

Unread post by Libero »

lux wrote:I have never subscribed to any of these dish TV services so I have no personal experience with them.

There are some things about them that I am skeptical about …

In looking at some web sites of these companies they seem to be saying that the dish must have a clear "line of sight" view in a certain direction and the presence of obstructions such as buildings, trees, etc will interfere with the signal and make installation problematic or impossible.

I would think this would be a major problem in large cities where there are lots of tall buildings.

Has anyone here had any experience with this situation? That is, they had a dish installed and then a building was erected nearby that blocked the dish and so their TV service stopped working?

And, what about communities that are located in valleys or near mountains that block the required “line of sight” view? Are there really no dishes installed in these areas?

Also, some of these dish web sites say that the dish only has to be pointed “toward the Southern sky” (Northern, I suppose, for down-unders). But “the Southern sky” is an awfully big area. It's half the entire sky, in fact. If the alleged location of the geostationary satellite is, say, behind an obstruction then how does the dish receive the signal even when pointed “at the Southern sky” in that case?

Lux,

I have had this problem once with a tree growing a bit too tall and its branches and leaves extending a bit into my dish's line of sight to its signal source. Also, from time to time it rains very hard (very rare in my neck of the woods) which causes interference. In my case from each of these experiences, this shows up as frozen and erratic images displayed on the set, or sometimes if it is very bad, the screen will go blank and it will tell you that it is trying to relocate the satellite. Sometimes but rarely and even in perfect conditions, certain HD channels will encounter issues but the non HD channel equivalent will be received just fine.
Last edited by Libero on Mon Aug 27, 2012 9:10 pm, edited 1 time in total.
lux
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Re: Satellites : general discussion and musings

Unread post by lux »

^ OK, thanks
whatsgoingon
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Re: Satellites : general discussion and musings

Unread post by whatsgoingon »

a
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fbenario
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Re: Satellites : general discussion and musings

Unread post by fbenario »

reichstag fireman wrote:
fbenario wrote:
reichstag fireman wrote:This seminal paper from 1926 authored by true pioneers (albeit American pioneers) Dr G. Breit and Dr M.A. Tuve.
The bolded phrase is an entirely unnecessary and bad faith slur that detracts from the clarity of your post.
It was intended to contrast the joke below, about the purloining of American research by the British. Taken out of context, of course it looks offensive. :rolleyes: Which leaves your sincerity open to question ;)
I didn't catch that connection, so it brings into question my concentration, not my sincerity. You likely already considered that not every reader would catch your subtlety.
fbenario
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Re: Satellites : general discussion and musings

Unread post by fbenario »

reichstag fireman wrote:From glancing briefly at the homepage and the wonkypedia entry, the system apparently supports "140 channels" of music at up 320kbps per channel. That's the sales blurb.. The truth on wikipedia is a system with a bitrate of just 39kbps per station or even worse. I'm listening to an MP3 at 173.2 kbps on the PC and that is only just pleasing to the ear. 39kbps ouch..

Another assumption here is that all 140 channels are available simultaneously. Probably not.. maybe 70 channels at most?
...
And that's how, even with a very low signal to noise ratio, given the appalling reception the tiny panel antenna in that device must provide, the bitstream from the skywave signal can still be recovered.
I find while cycling I get no static or dropped signals, and the sound is fine. It doesn't matter that it's not high-fidelity, since I have to permit enough road/ambient noise at all times so I remain aware of cars. Whether it receives 140, or just 70, station-signals at any moment matters not, since only one station can be chosen at a time.
Mickey
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Re: Satellites : general discussion and musings

Unread post by Mickey »

reichstag fireman wrote:
Mickey wrote:satellite radio channels...
a fully motorized KU-band/C-Band satellite dish
capture the entire Clarke Belt
the exact Satellite info
free-to-air sats

I used to be a big time satellite nerd

I will just leave it at that. :P
For a "satellite" nerd, we should expect scientific proof of their existence! :lol: And surely, those of an open-mind should not be using the same lingo as the alleged fraudster?!
The term satellite has been used by all and sundry in this thread. I do not understand why you are mocking my post here. What is the term that everyone has agreed to use instead of satellites? I will redact my post if you can point me to it. Also I do not have any scientific proof of it's existence or the lack of it. I explained in my post my areas of interest as it pertained to a hobbyist and an assembly level programmer of the microprocessors used in this area.
Further, I don't understand your reasoning: you say it's possible to get high bit rate "feeds" for sporting events, therefore the "satellite" must exist?
My post was an attempt at an explanation of video quality differences and the reasons behind it, specifically to address some points put forth by forum user Libero. I do not understand this conclusion from it? Was my post misleading or vague?
EDIT: Just to add.. what frequency is the SiriusXM system supposedly receiving "satellite" signals? Which "satellite" in the "Clarke Belt" *snigger!* is it purportedly using? The manufacturers seem strangely silent over this.
Silence? It is right there in one of the links I posted. This tells me you have selectively used portions of my post and it is somewhat expected given your position on this whole subject. I urge a little more discretion next time. Now these "satellites" could be all hoax, but there is no silence. "Satellite" hobbyists have known these for a long time.

http://www.lyngsat.com/XM-3.html
http://www.lyngsat.com/Sirius-XM-5.html
http://www.lyngsat.com/XM-4.html

I will re-read this thread in its entirety over the weekend, but I will maintain my stance about the evidence being inconclusive so far. Having said that I like any alternate theories that can lead to any kind of clarification on this subject since we know that several pieces of the satellite puzzle like the photoshopped launchers etc have been proven to be fake. But the null hypothesis cannot be rejected so far. ;)
reichstag fireman
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Re: Satellites : general discussion and musings

Unread post by reichstag fireman »

Dmitry wrote: Higher frequencies bypass the ionosphere and go to the space. See http://www.astrosurf.com/luxorion/qsl-perturbation6.htm or any other article on the MUF subject for reference.
Oh, come on, Dmitry, you know that NASA and its lackeys are fibbing!

A radiowave signal directed vertically into the ionosphere with respect to the ground plane has a maximum usable frequency (MUF) for ionospheric refraction of less than 10MHz (that's < 10 MEGA Hertz.)

However, as the angle of incidence for the radio wave is increased, the wave enters the ionosphere at an ever more oblique angle, and the Maximum Usable Frequency goes up and up! Right up to 10GHz (thats 10 GIGA Hertz) and beyond!

The concepts here are very simple.

In WWII, the practical application of Ionospheric Radiowave Propagation theory was taught to US military personnel over a fortnight in a very short course:

From: http://tf.boulder.nist.gov/general/pdf/2402.pdf
In January, 1944, a two-weeks training course in radio wave propagation was given by IRPL. It was for officers who were to be taught the principles of radio wave propagation and methods of problem solution and then assigned to overseas communication groups, where they could put on a scientific basis the assignment of radio operating frequencies in the field. Others were then to be sent to training units within the United States to organize courses in which additional officers could be instructed in this work.

The student body consisted of two groups, the first group consisting of eleven Army Air Forces officers, four officers from the Signal Corps, and three Navy officers, and the second group consisting of fifteen enlisted men and one officer from the Signal Corps, who formed the nucleus of the Radio Propagation Unit of the Signal Corps. The course comprised twenty-five lectures by scientists and others working directly in radio wave propagation, interspersed with problem sessions in which the students were coached in the solution of practical radio wave propagation problems.

As a further aid in determining the proper usage of radio frequencies, three handbooks were issued. The first handbook, "Radio Transmission Handbook Frequencies 1000 to 30,000 kc.," was issued in January, 1942, giving the basic principles of radio sky-wave propagation, and such computational procedures as were extant at that time, together with preliminary versions of prediction charts and predictions for the winter. A supplement to this handbook was issued June 1, 1942, which gave summer predictions.
That 1942 Handbook was referenced earlier in this thread. Not to be missed :lol:
reichstag fireman
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Re: Satellites : general discussion and musings

Unread post by reichstag fireman »

simonshack wrote:*
(brief 'off-topic' news flash - I apologize for interrupting this interesting technical debate with mere 'trivia'... :P )

FIRST EVER TRANSPACIFIC satellite TV broadcast (22/11/1963) :rolleyes:

I just bumped into this delightful tidbit of 'information'...
"Relay 1 was the first satellite to broadcast television from the United States to Japan. The first broadcast during orbit 2677 (1963-11-22, 2027:42-2048 (GMT), or 1:27 pm Dallas time) was to be a prerecorded address from the president of the United States to the Japanese people, but was instead the announcement of the John F. Kennedy assassination."
(...)
"In the three days following the Kennedy assassination, Relay 1 handled a total of 11 spot broadcasts; eight to Europe and three to Japan."

http://en.wikipedia.org/wiki/Relay_1#Relay_1
The "RELAY 1" communication satellite
Image

http://en.wikipedia.org/wiki/List_of_co ... ite_firsts

I don't know about you - but if this extraordinary 'coincidental happenstance' doesn't stink to high heaven to you - you may have to check your nostrils!

And - on the JFK State Funeral wiki page we learn that...
"NBC transmitted coverage of the procession from the White House to the cathedral by satellite to twenty-three countries, including Japan and the Soviet Union, allowing hundreds of millions on both sides of the Iron Curtain in Europe to watch the funeral. However, satellite coverage ended when the coffin went into the cathedral.
http://en.wikipedia.org/wiki/State_fune ... F._Kennedy
No mention whether this happened due to a fading signal or due to a momentary surge in inter-celestial respect. <_<
Hehe! great find! I often marvel at the variation in shapes and size of "satellites" !
reichstag fireman
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Re: Satellites : general discussion and musings

Unread post by reichstag fireman »

Mickey wrote:Now these "satellites" could be all hoax, but there is no silence. "Satellite" hobbyists have known these for a long time.

http://www.lyngsat.com/XM-3.html
http://www.lyngsat.com/Sirius-XM-5.html
http://www.lyngsat.com/XM-4.html
Thanks. Maybe it's worthwhile noting the following from the "data" published on that lyngsat website:

USA-wide coverage of the SiriusXM radio service is provided via multiple skywave signals, each with a completely different reception footprint.

The hoaxsters claim that these footprints are from different transponders on the same "satellite". Whereas in truth the footprints are from signals of six or more different skywave transmitters, located continents apart, but aligned to provide nationwide coverage in the USA..

See: http://www.satbeams.com/footprints?beam=6101

Recall that the point of refraction for skywave is preferably over the tropics, where the maximum electron density is found, for reliable propagation.

Therefore, assuming those beam maps are trustworthy, the likely skywave transmitter sites for the Sirius XM4 "satellite" are in (1) Australasia (providing coverage over Eastern USA) and (2) South America (providing coverage over Western USA) *

Image

* possibly sited off the south east coast of South America..

As an aside, this is perhaps where we should focus on Google. Could it play its own role in the satellite hoax? How helpful it would be to the hoaxsters if Google strategically placed a large rain cloud on its online maps, to hide the aerial view of a main skywave transmitter site!
Heiwa
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Re: Satellites : general discussion and musings

Unread post by Heiwa »

reichstag fireman wrote: A radiowave signal directed vertically into the ionosphere with respect to the ground plane has a maximum usable frequency (MUF) for ionospheric refraction of less than 10MHz (that's < 10 MEGA Hertz.)

However, as the angle of incidence for the radio wave is increased, the wave enters the ionosphere at an ever more oblique angle, and the Maximum Usable Frequency goes up and up! Right up to 10GHz (thats 10 GIGA Hertz) and beyond!
:lol:
Image

The Ionosphere is the greatest layer in the atmosphere with the least air but still radio waves may refract there. Why not? Most satellites are located just above the top of the Ionosphere to avoid friction with any air and are very difficult to spot by the naked eye maybe due to refraction? Or because they are so far away.
When a satellite enters the atmosphere for any reason, the air will start to brake it and the associated friction heats up the poor satellite which suddenly catches fire and becomes smoke! :rolleyes:
Last edited by Heiwa on Tue Aug 28, 2012 8:33 am, edited 1 time in total.
hoi.polloi
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Re: Satellites : general discussion and musings

Unread post by hoi.polloi »

I see what you mean Heiwa. It does seem very convenient to the story, if there were fictional satellites in this zone.
As an aside, this is perhaps where we should focus on Google. Could it play its own role in the satellite hoax? How helpful it would be to the hoaxsters if Google strategically placed a large rain cloud on its online maps, to hide the aerial view of a main skywave transmitter site!
I see your reasoning. And yes, while browsing Google Earth (before it stopped working for me for some reason) I would often focus on tiny parts of the world I knew nothing about - only to encounter a convenient cloud formation directly over an island. This is understandable for many Dmitry-like excuses, but shouldn't Google have the power to penetrate such inconveniences and show us this land? I guess some wealthy people are buying privacy. Hard to find in some capacity, these days.
whatsgoingon
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Re: Satellites : general discussion and musings

Unread post by whatsgoingon »

a
Last edited by whatsgoingon on Fri May 24, 2013 10:29 am, edited 1 time in total.
reichstag fireman
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Re: Satellites : general discussion and musings

Unread post by reichstag fireman »

whatsgoingon wrote:Image
RF, why not have two terrestrial assets covering N. America in this case? I see two lobes essentially.
Sure. That's what I meant, at least for "satellite" XM4... two transmitter sites - one in australasia, one off south america, to provide coverage across north America.

Also, since the "satellite radio" service is supposedly provided by "satellites" * - XM1, XM2, XM3, XM4, XM5, Sirius FM5, Sirius FM6 that would require at least seven transmitter paths.

Returning to the bandwidth requirements, since we now have at least 14 transmitters supplying up to 140 radio stations. The bandwidth of each transmitter signal must be far less than originally estimated. And we guessed earlier that perhaps only half the radio stations (70) are available at one time. So if the maths is right, the raw throughput per transmitter without compression is not even 500kbps. This is close to the bandwidth that radio hams can achieve.

* To better understand the role of skywave, we should ignore the word "satellite" and focus instead on "transponder". If two skywave signals have very different reception footprints, as we can see above with SiriusXM4, then the "transponder" signals must come from two geographically apart transmitter sites. The idea that the two signals are transmitted from the same point in outer space is even more obviously untrue.
lux
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Re: Satellites : general discussion and musings

Unread post by lux »

We pause briefly for a musical interlude ...


full link: http://www.youtube.com/watch?v=YuA-fqKCiAE

BTW, the Telstar satellite, launched on 1962, is still whizzing through space above us, we're told. But, it is not the oldest still-orbiting satellite -- that honor goes to Vanguard 1, launched in 1958.

Amazing how these half-century-old satellites can remain in orbit when they couldn't possibly have any remaining fuel or means of orbital correction yet modern satellites require these to keep from crashing to Earth or veering off into space. I guess it's yet another example of the devolution of aerospace technology.

It also demonstrates that there is nothing to fear from the dozens of meteor showers that pelt Earth each year, some lasting for months. All one needs is a little luck, evidently.
Last edited by lux on Tue Aug 28, 2012 4:40 pm, edited 1 time in total.
Dmitry
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Re: Satellites : general discussion and musings

Unread post by Dmitry »

whatsgoingon wrote: But what you have left out all along is that GHz can be propagated in the local area by tropospheric scattering. This is an old military technology. http://en.wikipedia.org/wiki/Tropospheric_scatter Seems 2-10 GHz is easy enough to use in this way, no?
Not at all. Do you ever read sources you are referring, whatsgoingon? OK, I'll do it for you.
Tropospheric scatter (known as "troposcatter" among practitioners) is a method of transmitting and receiving microwave radio signals over considerable distances – often up to 300 km.
Madagascar? Algeria? London seems to be a bit farther.
Normally, microwave signals, transmitted at various frequencies, usually around 12 Gigahertz (GHz) or 19 GHz, are only used for ‘line of sight’ applications, where the receiver can be ‘seen’ from the transmitter.
Roger So Far
However, tropospheric scatter signals use a frequency of around 2 GHz. Frequencies of transmission around 2 GHz are best suited for tropospheric scatter systems as at this frequency the wavelength of the signal interacts well with the moist, turbulent areas of the troposphere, improving signal to noise ratios.
Not 10 GHz. Only 2 GHz. For 300 km. Only 300 km. Every 300 km?

But now is the punch time:
Tropospheric scatter is a fairly secure method of propagation as dish alignment is critical, making it extremely difficult to intercept the signals, especially if transmitted across open water, making them highly attractive to military users.
.

Troposcatter is by nature only point-to-point communication, it is not at all suitable for broadcasting.
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