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Making A Radio Telescope


MeanEYE

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the radio software used with the other DVB-T mods i saw running,

showed them scanning all frequencys.

the GUI showed a waterfall type readout with various readouts.

they plug in the usb, run software, and dial in via mouse to a signal.

the video link shows the software based usb reciever in action.

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soooooooooo is the idea for the radio scope origionally a dish because of the similar shape to the professional radio scopes?

normal DVT usb things have a small problem in that they are limited to frequency, where the proper one thats been made and sold is open to most frequencys but it is only designed really for amsats

id love to use my migila firewire DVT to do this as it works perfectly on my mac is this possiable?

1. No, the idea of a dish was because the higher in frequency you go the smaller the wavelength gets, you can concentrate the received signal better in to a smaller antenna with a dish.

2. Again not really, the DVB-t and the funcube dongle are very similar in design (same chips), they both cover exactly the same frequencies, the funcube dongle has a built in sound card that passes the signal to the PC, this allows narrower bandwidth for satellite communication, which is what it was designed for, the DVB-t on the other hand does not have a built in sound card and passes the raw data to the PC for decoding, this allows for much greater bandwidth as associated with TV/FM radio signals.

3. I have no idea if the migila firewire DVT will work, the magic ingredients seam to be the Realtek RTL2832U / E4000 combination of chips.

@Gina your block diagram seems to fit the DVB-T/funcube quite nicely, the digital radio work I do normally involves the sound card as an ADC.

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Just found this thread and very interesting read. I'd offer to help but I know absolutely nothing about this topic. But if you get this up and need a spot in the U.S. to put up a small dish I got a couple acres that I could put one up on possibly.

In regards to several of you mentioning frequency in regard to wifi I have a bit of information that might me useful. I watched a news clip several weeks ago about a special quite zone over here in the U.S. in Green Bank, West Virginia. Its actually several thousands of acres in area and covers several states but its center is in WV. This quite zone actually mandates that cell phone use and wifi use is prohibited and its actually federal law! All to reduce interference on a very large radio telescope locate in WV. Granted its a huge telescope that can pick up the faintest of signals but I'm sure it would apply here as well. Sorry I can't explain more but I'm sure all of you that know more about this than me can gleam something from it....hopefully...maybe I'm just way off lol.

Oh the name of the observatory is the Green Bank Telescope. Here's the link to thier website. Hope its helpful.

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sooooo reading around the subject these threads might hold the key to what we wanna do

soooo from what i gather we need is a dish a interface between the dish and a computer, (the usb tv tuner toodaaa) and a basic mount (can be upgraded to motorised lateron)

if some one can suggest specific equiptment i can give it a go on making:)

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Ok, I have just about persuaded myself to MAKE a 3m dish. The plan is to use plywood formers cut to precise sections every 10 or 20 cm to give an exact paraboloid, then infill with styrofoam and sand to shape. Not sure what to cost it with yet but am considering aluminium foil carefully cut to avoid creases andglued down. Any body have any better ideas?

Will then try to follow instructions in that Brit Astros article.

With any much, at least the dish will be ready to show at PSP2011.

Will post updates on progress here.

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That's a nice ambitious project :) Good luck - I await pics with great interest :)

Many people seem to use wire mesh for the dish. Don't know if chichen wire is suitable :D

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That's a nice ambitious project :) Good luck - I await pics with great interest :)

Many people seem to use wire mesh for the dish. Don't know if chichen wire is suitable :D

Thanks Gina,

call me a perfectionist (or mad - up to you!) but I want to get surface accuracy down to a couple of millimetres at most. Turkey foil seems to be the lowest tech but I am becoming intrigued by the "electroless nickel coating" techniques I am looking at at the moment. I feel a few phone calls coming on tomorrow :)

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Seen some HD satelite starter kits for 40 pounds from B & Q most likely probably 45cm dishes

also seen some in local maplins 60cm folding satelite system no lnb like

these look interesting easy to move around.

http://www.maplin.co.uk/60cm-folding-satellite-dish-529706

wounder if any them would do

mite get starter kit sometime someone else would have to make all other stuff like ;)

if i get dish can add me to list sats to join array :)

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Just spotted this thread and reading with interest, I came across this at my work, this may give a good guide as to what other sources of "noise" could be lurking right across the RF spectrum. Also points out useful Radio Astronomy frequencies.

http://www.roke.co.u...allocations.pdf

HTH

Keith

My God! It's full of noise!!!

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i am back.

had a play with one of those dvb-t dongles, and software. a big fail it was and waste of the £25 spent on the device. and had more chance standing naked with a tinfoil hat on to get a radio signal. spent two days solid downloading/updating/shifting stuff, listening to my own voice being picked up by the dongle, and computer crashes.

but now i have an E4000 and a RTL2832u reciever chip. 64mhz to 1.7ghz. not sure it can be used for anything in this project maybe hooked to a arduino to gather what data is needed.

the chipset allows data direct to pc via I/Q .

now looking for a LNB and dish, i know this lowtech version will work better than the more hightech SDR idea. but maybe it can be salvaged somehow into this project.

my idea is a dirty cheap satellite dish and lnb, fitted to a signal meter and powered with whatever i can find.

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Welcome back :)

Great that some experimenting is being done on this - well done and good luck :) I am not yet in a position to be able to contribute, I'm afraid, but hope to in the future.

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Right, we have quite few dish builders / buyers - anybody any good at low noise amps? I am going through the various bits & bobs I can find about dish design and should be able to publish a table of likely beam width and gain by frequency for each size dish; combining this with the information posted above by various people should give us a good idea what frequencies we can look at - this will tel us what ranges we want to optimise the amps for.

Anybody up for building the amps or know a good off-the-shelf system we could use?

Anybody else want to look at wave-guide / feeder design?

Anybody else want to run with the cooling bits? I am looking after an office re-furb at work at the moment; talking to the air-con people, car air conditioning are probably going to be simplest and safest to modify and could be a good alternative to peltier coolers.

J.

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