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Flat Panel Antenna for C-band TVRO?

Posted by Cliff on from the ditching-the-dish dept.

Anonymous Coward asks: "Does Slashdot know of any anyone who makes a flat panel antenna for C-band Satellite TV? The only makers of commercial flat panel antennas that I'm aware of is this one, but it's only KU-band."

11 of 26 comments (clear)

  1. Huge? by BigZaphod · · Score: 2

    Wouldn't a flat panel for C-Band need to be rather huge? I'm not that familiar with how that stuff works, but it seems there had to be a reason why the BUDs where, well, big.

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    1. Re:Huge? by JCMay · · Score: 4, Informative

      Yep. It'd be in the realm of the same size of a C-band dish, about ten feet across. I've seen Ku-band fixed beam arrays like the one mentioned, but I've not seen a C-band array like that.

  2. hmm by sn0wman3030 · · Score: 5, Funny

    I can tell this is going to be a popular thread.

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  3. Suggestion by Anonymous Coward · · Score: 3, Funny

    Have you tried contacting KU and the Sunshine C-Band?

  4. One site by Hungus · · Score: 3, Informative

    One site shows pics and says they have at least prototyped a flat panel c-band antenna:
    http://www.skygate.bg/skygate/Acivities/SampleProd ucts.htm They are a Bulgarian company with Dutch backing partnering with AlcaTel I might be a bit difficultto buy one from them however.

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    1. Re:One site by Isao · · Score: 2, Interesting

      FYI, that's not a C-Band antenna, that is a C-Band feedhorn (the part that goes at the focal point of a parabolic or spherical dish).

  5. Build your own by unitron · · Score: 4, Interesting

    About 20 years ago Radio-Electronics magazine had an article on building your own out of plywood. Really. It used concentric rectangles that worked as a sort of lens at those frequencies. Like microwave waveguides that somehow use empty spaces as antenna elements, the physics involved was way over my head.

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    1. Re:Build your own by JCMay · · Score: 2, Informative

      I saw something similar to this a few weeks ago at an Engineers' Week presentation. One company was showing their planar "parabolic" reflectors. It was basically a fixed-beam rectangular reflectarray that duplicated the funcionality of a parabolic dish. It would still need a feed at the focus of the reflectarray.

  6. ok by Monkelectric · · Score: 2, Interesting

    This sounds really cool but WTF does any of it mean? :) Please drop some knowledge on me

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    1. Re:ok by N3Bruce · · Score: 5, Informative

      C-Band operates in the 4.7 Ghz range, and predates current DSS systems, such as Direct TV et.al. It operates primarily in analog mode, with most of the channels of the newer systems, though sadly most commercial signals are scrambled these days. Most of the free stuff is things like religious broadcasters, HSN, QVC and their clones, public affairs stuff, and so on. Programming meant for other countries is sometimes not scrambled, and you sometimes find some interesting stuff. No it is not nearly as interesting as the days unscrambled wild feeds or even chipped videocipher units, but there is an occasional nugget out there for the C-band surfers.

      C-Band signals with a good antenna look better than DSS because the signals are analog and operate on lower frequencies than the DSS Stuff. They suffer less from rain fade than the higher frequencies, and compression artifacts from the digital modes. My parents have a big dish I helped install in the late 80's. They retired to a rural area beyond the reach of cable and the nearest TV station was 75 miles away, so the big dish was really their only option then. It still looks great today, though if they had to start over from scratch they would opt for the small dish. They use a small dish for their motorhome when they travel, and a small dish for broadband internet.

      That being said, the big dish's main drawbacks are its size, with 6 footers being the minimum to get a decent signal, and the fact that there are only 24 transponders on each satellite. This means that unless you want to install multiple dishes like the cable companies, you need a way to steer the dish, which adds a layer of complexity to the operation and maintenance of the dish.

    2. Re:ok by michael_cain · · Score: 2, Informative
      The most interesting flat-panel antennas -- where the structure is literally a thin, flat panel rather than depending on a parabolic dish -- are phased-array designs. I always thought that phased arrays were a really neat concept. Explained badly, they consist of a collection of small individual antennas and the signal from each runs through a very precise time-delay element. By adjusting the delay elements, it is possible to use constructive interference to "point" the antenna in a particular direction. The result is a steerable antenna that has no moving parts. If I remember correctly, much of the original work in making them practical was paid for by the US Air Force -- because radar antennas with moving parts tended to freeze up badly in the Arctic. I believe that the big application in consumer electronics is going to be with Ka-band satellites. The FCC is going to allow those birds to be spaced much closer together than the older Ku-band satellites, and the stamped-metal dishes are not selective enough.

      Real experts should chime in here and correct my errors.