Talk:Communications satellite/Archive 1
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Perhaps it would be better to not imply that fiber optic communications do not experience a path delay. A common lab experiment for university students is to calculate the speed of light by measuring the path delay through length of fiber optic cable.
--Guggemos 00:26, 8 Dec 2004 (UTC)
Hermann Noordung's famous 1929 book, "Das Problem der Befahrung des Weltraums", in which he first proposed communications satellites in geostationary orbit, was re-published in facsimile in 1993 by Verlag Turia & Kant of Vienna, ISBN 3-85132-060-3.
The opening for this article states that modern comm satellites are in geosynchronous orbits. The Telephony section describes the satellites for this purpose as being in geostationary orbits. Is this accurate? --Moppet 20:14, 4 February 2006 (UTC)
I've heard roumers saying its only USA whos got communications satellites in the space, or that they control all of them. And it has been used in the war too confuse enemies. Is that right? - 22.214.171.124 08:22, 3 August 2007 (UTC)
I've already made major changes to the article and am considering adding a section on spacecraft design (subsystems, equipments, etc.)
Opinions? --Philopedia 7 July 2005 17:33 (UTC)
Removal of Section
I am removing the latest addition ('Extraterrestrial communication satellite'). Although such satellites do indeed transmit results of various scientific results back to earth, this is still a departure from the generally accepted notion of what is meant by a communication satellite.
In fact, every active spacecraft communicates, if only to report on their own health and status. The term communications satellite is used in a narrower sense to denote generally commercial or military applications designed to support either broad information desimination (e.g. TV transmission) or two way communication (e.g. telephony). This definition excludes applications such as weather satellites, remote sensing satellites and interplanetary missions, all of which communicate payload data to the ground.
I suggest that the author of the new section look into reintroducing the material in an article on scientific satellites.
--Philopedia 03:19, 24 July 2005 (UTC)
- special purpose relay systems (that comprise the NASA DSN) need to go in somewhere. They probably don't fit the scope of an article on (terrestrial) communications sats, but since their only function is communication, they don't really fit in a discussion on scientific spacecraft either. Matt Whyndham (talk) 06:58, 30 November 2009 (UTC)
I do not understand the first two sentences:
"The first and still, arguably, most important application for communication satellites is in international satellite."
...is in international telephony? is in international satellite telephony? What goes here?
- It's easy: and international communications satellite relays television, telephone, computer data, Internet traffic, and everything else from one country to another - and especially over the oceans, e.g. America-Europe; America-Japan; Europe-Australia. The very first active communications satellite, Telstar 1 relayed either television or phone calls, and so have the others since then. So, there is no implication of telephony for communications satellites. Someone jumped to a conclusion on that one. The first uses of these satelltes were for transatlantic communications, and the other equatorial oceans came just later.
"An analogous path is then followed on the downlink."
there is no reference to what the analogous path is, or the previous action that would warrant a 'then'.
- yes there is, but it's not especially well written, nor a particularly good use of the word "analogy". The UPLINK is the path from the source of the signal from the ground to the satellite, previously described in the paragraph. The DOWNLINK path is how the signal gets from the satellite back to the destination, also on the ground. It follows a similar (but reverse) series of steps, hence it's an analagous path. Matt Whyndham (talk) 06:54, 30 November 2009 (UTC)
well i dont rely understnd the article...i just wanna ask some questions for my assgnment..
1. What are the function of Satellite communication anyway? State atleast 4...
2. What are the transmitting and receiving frequency for satellite communication?
3. Satellite are equipped with multiple repeaters which we call relay station right?? so can u tell me more about relay station but make it simple ok...
- WP is not a place to get personal help with your homework. Matt Whyndham (talk) 06:49, 30 November 2009 (UTC)
In the *External Links* section on this page, and a number of other satellite-related pages, I've reverted links to www.prmt.com, similar to this one:
I've done it on the basis that the link is a commercial one and appears to me to be against WP:EL.
The links keep getting put back though, and since I don't want to appear to be undertaking a vendetta against prmt.com I'd like to take the view of other editors.
Is this link approapriate to this article, or should it be deleted on the basis of WP:EL?
MarkPos 21:23, 23 October 2007 (UTC)
Some More Questions
I was reading a recent article about NASA and how the director's difficulties with support from the Federal Government. This got me to wondering a couple of things.
Is there any indication on approximately how many privately owned satellites there are floating around the Earth?
How do private companies (such as cable companies and cell phone companies) launch their satellites? Do most of them have their own launching facilities, or do they have to rent space and equipment? What does this kind of thing cost? Can NASA benefit from it by leasing locations and equipment?
- Yes, a quick clance at the long See Also section shows me no Wikipedia article about the shape of the orbital lift industry, how the launch sites are all government owned, the rockets mostly developed from ICBMs for the Cold War, the worldwide rate of a few launches per month, the hundred or so satellites alive at any one moment and the thousands dead, launch insurance, slot allocation and so forth. This stuff ought to be written by someone who knows more about it than I do. Jim.henderson (talk) 16:19, 21 September 2008 (UTC)
- practically all comms sats are commercially built (even the sekrit military ones). NASA and the DOD try and push launch services to the commercial market whenever they can, as it's not their core competance. Even odd things like the Shuttle are put together by a bunch of contractors. As for the customers, the cable/TV co's and phone co's, they do not have any satellites. But they buy capacity - probably through intermediary companies who operate "backhaul" networks for them - from the providers of satellite services (who are connected with, but not always the same as, the enterprise that owns the satellite)! @ Jim .. WP is a bit weak on general surveys! Matt Whyndham (talk) 06:47, 30 November 2009 (UTC)