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Thread: how to make home-made dish?

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    Quote Originally Posted by rayman1366 View Post
    i call austech users as my friends.
    is it a fault?
    No, no problem with that.

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    You said you used software to design the curve (parabola).

    You've been told repeatedly that you need to form metal sheeting and how to do it, but you keep asking the same questions and now you say "interesting ideas maybe not expressed yet".

    Sorry if you think the factual, accurate answers and information provided by members are not interesting.

    I gave you a link to a website that has step-by-step instructions how to build your own dish.... did you even read it?

    tristen also provided you with a link to several DIY dish projects.

    There is no point continuing to repeatedly ask questions that you have already been given the answers to.

    Now that you have the information, it's up to you to actually build the dish if you think you can manage it, or get someone else to physically help you, or abandon the idea.

    As mentioned, IPTV, (with a VPN to block your location) is probably a far better and easier option for you, with no visible dish that may draw unwanted attention to you.

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    Quote Originally Posted by mtv View Post
    You said you used software to design the curve (parabola).

    You've been told repeatedly that you need to form metal sheeting and how to do it, but you keep asking the same questions and now you say "interesting ideas maybe not expressed yet".

    Sorry if you think the factual, accurate answers and information provided by members are not interesting.

    I gave you a link to a website that has step-by-step instructions how to build your own dish.... did you even read it?

    tristen also provided you with a link to several DIY dish projects.

    There is no point continuing to repeatedly ask questions that you have already been given the answers to.

    Now that you have the information, it's up to you to actually build the dish if you think you can manage it, or get someone else to physically help you, or abandon the idea.

    As mentioned, IPTV, (with a VPN to block your location) is probably a far better and easier option for you, with no visible dish that may draw unwanted attention to you.
    unfortunately my english isnot so good to transfer my ideas.
    when i told that instructions expressed here so far isn't interesting?

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    I came across this image while doing a search, which I think is quite a nice way to start something like this project:



    The blog is here:

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    Quote Originally Posted by AdrianR View Post
    I came across this image while doing a search, which I think is quite a nice way to start something like this project:
    The pic was in the link I posted in post #6

    It's hardly a 'stealth' look.... probably do the exact opposite... attract a lot of attention.

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    Quote Originally Posted by mtv View Post
    The pic was in the link I posted in post #6

    It's hardly a 'stealth' look.... probably do the exact opposite... attract a lot of attention.
    Oops sorry! I honestly did not think to check.

    Yep, definitely. So, the OP has decided to abandon the project I assume? No further posting for a while.

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    Quote Originally Posted by mtv View Post
    All dishes require a metallic-type surface to reflect the signals.

    Eg: fibreglass dishes have a metal sheet embedded.

    Materials that do not permit satellite frequencies to be reflected must incorporate a reflective material (eg: metal sheet/mesh) that will reflect the signals into the feedhorn.
    Several years ago I made a number of fibreglass dishes using carbon fibre reflective surfaces.
    I vacuum moulded a glass epoxy outer skin, 6mm. structural PCV foam and a single carbon fibre inner reflective surface over a metal 90cm dish. During my experiments with carbon fibre, I tested equally sized metal and carbon fibre dishes against one another and there was no discernable difference in performance. My quest in experimenting with carbon revolved around the ability to mount a combined level and compass directly on the back of the dish to enable quick, simple alignment and I can normally set it up in a few minutes [using a Satlink WS 6906]
    I still use one of these dishes when travelling; it weighs about 1kg. complete with carbon fibre LNB mount.
    Metal is not required to reflect satellite signals.

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    Quote Originally Posted by premsat View Post
    Metal is not required to reflect satellite signals.
    Technically, that's correct, just that most dishes use some form of metal as the reflective surface.

    Yes, you could use anything that reflects the desired wavelength.

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    Yep, there are many non-metallic elements that are also just as reflective as metal, carbon being one of them. Also, if it weren't so hard to get hold of - boron, silicon (metalloid, not silicone the sealant). I suppose alloys of these too.

    Yeah, and then of course, the advantage of carbon fibre - the immensely lighter mass, as you have mentioned premsat.
    Last edited by irritant; 03-12-16 at 04:15 AM.

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    Quote Originally Posted by mtv View Post
    I seriously doubt a 1.8m home-made dish would provide any increase in performance compared to a 100cm commercially-made dish due to the commercially-made dish having far greater accuracy of the surface and I'm also assuming the commercially-made dish is one-piece, which will perform better than a petalised dish of the same size.

    Ku-Band dishes require much greater surface accuracy compared to C-Band dishes as the slightest imperfection will cause signal degradation of the much shorter wavelength Ku frequencies.

    As I mentioned previously, to obtain a curve in sheetmetal, it has to be rolled.

    If you don't have access to a roller, the sheet can be formed over a cylinder, such as a pipe.
    Ku band dishes certainly must be accurate - some of you may recall a photo that I posted [pre meltdown] of an LNB mounted on a metal garbage bin lid happily running Optus Aurora with 65% signal quality!

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    I've always wondered how those transparent dishes work. They are completely see-through and have no metal (as far as I can tell). Isn't it also perhaps the smoothness of the surface as much as the material (and it just so happens that metal gives the smoothest surface) that is important? If you could mold/curve say glass in such a shape, would it not work?
    Last edited by irritant; 04-12-16 at 04:48 AM.

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    A dish is an RF reflector. It has to be RF inductive, ie. metal, or another material that can be magnetically induced by RF. Glass, plastic, etc. is non-inductive and won't work.

    A few years ago, I had an idea to make a 'discreet' satellite dish from a small, solid-walled, above-ground swimming pool.

    The idea was to ½-fill a circular swimming pool with water, then seal the vinyl cover that comes with the pool, to the pool rim with silicone. Then a tap would drain some of the water out of the pool, this would create a moderate vacuum in the air-space under the cover. This vacuum should be enough pressure to stretch the previously loose vinyl cover into a nice parabola.

    I was thinking to try aluminium-based paint as the reflective/inductive surface. I have a hunch it would work, but if it didn't, I was going to use a bunch of 'catering' aluminium foil-wrap and line the dish with it.

    Of course, the dish is just pointing directly overhead and isn't much use if unless you have a satellite directly overhead. But the dish is also very big, so even a small section of it would have the same reflective strength as a small dish. I was thinking of have a 'steerable' LNB, similar the Arecibo radio telescope in Puerto Rico. It still would work best with satellites that are as close to overhead as possible, but I think it would still work for strong satellites down to about 45° from the horizon.

    Hope this pic makes it a bit clearer.



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    When I first read the title of this thread, I thought you want us all to give you a recipe . That's maybe I'm a little hungry right now.

    However, it easy to buy one than to build one, regarding money and labor. But I guess your region don't offer you one to buy. Still, you should be looking for one.
    When there is a customer, then there is a product.

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    Just because you can see through something doesnt mean its also clear to RF waves.
    Who has had a problem try to use a camcorder with Auto Focus through a window ?

    At a guess I would say that clear dish AdrianR mentions has metal filings mixed into the dish material to make it RF reflective.

    I was told to make the Sydney suburban Train windows block out the heat and glare of the Sun, copper fillings were mixed into the glass.
    I stand unequivicably behind everything I say , I just dont ever remember saying it !!

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    Quote Originally Posted by gordon_s1942 View Post
    Just because you can see through something doesnt mean its also clear to RF waves.
    Who has had a problem try to use a camcorder with Auto Focus through a window ?

    Autofocus in cameras usually employs infrared or ultrasonic.... not RF, but yes, there are also metallic tints used on some glass and vehicle windscreens.

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    I was aware that Focus was IR and not RF but I used that as an illustration to show that what may appear clear to the eye may not be to other frequencies.

    Remember the warnings on those 'Through the Glass' mobile phone antennas that apart from the demister wire(s) embedded in the glass, it may also contain other material that could affect the operation of the antenna.
    I stand unequivicably behind everything I say , I just dont ever remember saying it !!

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    How is your dish coming along rayman1366? Do you perhaps have some pics?

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    If someone has a copy of the ARRL Antenna Handbook written in the 70's, they had pics and illustrations of 'Home Brew' satellite 'dishes' made out of bamboo for the ribs and wire mesh for the dish.
    This made a dish about 3 or 4 metres in size, was very light and easily bent into shape by using cords.
    Back then a dish of that size was both expensive and needed massive mounts apart from taking up space.
    Most likely many of the amateurs who experimented back then lived in the cities so they made these up so they could transport them to any open space available.
    I stand unequivicably behind everything I say , I just dont ever remember saying it !!

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    rayman1366, Your new post is noted again.

    For a one of dish you'd be up for thousands of dollars in tooling,
    Nowadays you can buy a 1.8m mesh dish kit for around $120 or a 2.3m for around $200 which take less the half hour to assemble.
    Last edited by B52; 19-07-18 at 12:25 PM.

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    After seeing the variations of dish's used on Caravan/Mobile Homes on the Tour d' France (SBS), picking which you like is the hardest choice.
    Somewhere in the Fog of my memories, Garbage bin lids have been pressed into service but today like B52 says, buying premade is the fastest way to go and it will work immediately unless your really madly keen on experimentation.
    A respected member (Learjet) came up with some interesting ideas on dish construction some time back. Not sure if they'd stored somewhere.
    I stand unequivicably behind everything I say , I just dont ever remember saying it !!

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