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Using a Small Satellite Array as C-Band Receiver?
An anonymous reader asks: "Many local zoning ordinances prohibit big (6~8 ft) satellite dishes. Is it possible to use many smaller dishes to achieve the same effect as one big dish in picking up C-band transmissions? I know that moving large number of dishes, for satellite tracking purposes, would be a pain but are there any other issues?" Obviously building a satellite array is possible, but what are the engineering issues involved in building such a project? How much space is realistically needed? And, of course, the bottom line: how much would doing something like this cost?
Is it possible to use many smaller dishes to achieve the same effect as one big dish in picking up C-band transmissions?
Yes.
More detail?
Yes, do a google search on multiple antenna and radio astronomy. The math gets hairy sometimes, but it can be done. Might be more trouble than just getting a Dish Network thingy installed.
If tits were wings it'd be flying around.
For those slashdotters like myself who found themselves asking a bajillion questions when C-Band was mentioned, check out the TVRO FAQ.
And just in case your wondering what TVRO stands for, here is a description of TVRO from the FAQ's introduction:
"TVRO is an acronym that stands for TeleVision Receive Only. Generally speaking, TVRO is the satellite distribution system for delivering programming to cable TV headends and systems."
Also, here are some interesting facts I gathered from googling around and reading the FAQ:
C-Band video is studio quality, it blows away cable and DSS/DISH satellite systems.
Commercial PPV stations like HBO are available but need decryption hardware.
Channels are leaving C-Band and switching to digital broadcasts, so the availability of C-Band channels is dropping.
Non-commercial much less homogenized content is available via satellite.
It's a bleeding edge technology, that you could build at home. Here are some examples and references:
JPL - NASA progress report on a fresnel zone lens.
Zone Plate (reflecting) Fresnel Antennas for Amateur SETI -- Part 1
You'll have to dig, but also use Google to find it.
You should be able to design a flat antenna from solid foam insulation with foil on both sides by removing the foil at the right places. There are design programs to do the math. Aiming is going to be tricky, but should be no more difficult than any other installation.
Good luck.
--Mike--
What you want to do is called Aperture Synthesis (or Inferometry) - It's what the VLA uses to combine the signals from it's 27 25m dishes to work like a single 130m dish.
There is some information on theory here, but I think building a device to actually do what you want will be very hard. Good Luck!
Many local zoning ordinances prohibit big (6~8 ft) satellite dishes.
If you are actually talking about government zoning and not covenants, conditions and restrictions (CC AKA deed restrictions), you're in luck. Get an FCC amateur radio license (anyone can get one for the $10 and a very basic understanding of electronics) and tell folks its a ham antenna. Don't mention TV reception.
The FCC's PRB-1 (here and here) is a limited preemption of zoning ordinances. Basically, local government must reasonably accommodate folks when it comes to antennas. A C-band dish in your back yard would certainly be reasonable.
(You may also want to bluff with Section 207 of the Telecommunications Act of 1996 which says that folks must allow dishes. It generally only applies to dishes less than a meter but some people won't read the entire document if you have a good poker face.)
Is it possible to use many smaller dishes to achieve the same effect as one big dish in picking up C-band transmissions?
Yes. Hams have beeing builing arrays for years to do moon bounce and whatnot. You can find some over the top pictures here. However, the infrastructure to create such a monster is substantial and is likely to run afoul of the same local ordinances you're trying to work around.
Overall, I don't see the point in using a big dish for TV anymore and an array of smaller dishes to act like a bigger dish seems pointless.
InitZero (k4mls)
Generally, anywhere on the planet, C band offers at least 1500 channels.
Besides, he never said he was going to watch it afterward...
Or simply put in a toolshed with a fiberglass roof instead of a steel one. Would local zoning prohibit a 9' - 12' square toolshed too?