Anyone tried to make BIG dish at home?

***BombedOne*** · 11-09-2008

Unfurtunately - can't. Since this was built in customer private property. No photos were taken, upon his request.

Juan54321 · 11-09-2008

I have been using my homemade concrete 3.2 meter dish on the costa blanca for about four years now. I used a plywood former on a homemade bearing arrangement to "cut" the form in a .6 l/d format ( cheap offset LNB) I used kitchen foil glued on in 30cm triangels to reflect radiation, painted white with emulsion after getting a bit burnt during set up lol. I get BBC2 until about 7pm. Used to be 9pm but a lot of foil has peeled off.

**T_G** · 11-09-2008

Originally Posted by Juan54321

I have been using my homemade concrete 3.2 meter dish on the costa blanca for about four years now. I used a plywood former on a homemade bearing arrangement to "cut" the form in a .6 l/d format ( cheap offset LNB) I used kitchen foil glued on in 30cm triangels to reflect radiation, painted white with emulsion after getting a bit burnt during set up lol. I get BBC2 until about 7pm. Used to be 9pm but a lot of foil has peeled off.

Nice one Juan!
Can you post some pictures? (please no links, post the actual pictures here).

Thanks, TG

***BombedOne*** · 11-09-2008

perkis.narod.ru/Tv_technolog/parabol_ant/an-stv.htm

here's instruction about how to made mold from concrete and dish from fiberglass cloth. This one uses a bit different approach than in my book, but also seems to be good.

Page is in russian, you can use babelfish.yahoo.com for free online translation.

Juan54321 · 11-09-2008

Originally Posted by T_G

Nice one Juan!
Can you post some pictures? (please no links, post the actual pictures here).

Thanks, TG

I seem to have lost my construction pictures but I'll include a picture of the dish. I've still got the plywood template with bearing pole attached if anyone is interested.

The material cost was very low but it took about 10 days work to make the template, construct the dish, stick the foil and paint.

I mounted the pole with template pointing at the satellite using poles to support high end and the lower end set in a block pillar. I then simply build up behind the template with blocks, cement, any old rubble I had. When I was within about 3 cms of the template in any position I applied a layer of fine concrete, repeated with strong cement mix, then once more with a creamy cement mix which I wiped to the exact curve by rotating the template.

I stuck the foil on shiny side down using a waterproof pva glue.

A few problems. Even with the dull side of cooking foil exposed you have not got to get to close to the focal point in Spain to feel a great deal of heat at certain times of the day. I had to paint it before something caught fire! The foil bubbled up in places. I pricked the bubbles and restuck but after a couple of years it started to peel here and there. I originally planned to use aluminium powder suspended in varnish and just brush on. At the time their was a lot of terrorist activity and I did not fancy mail ordering a known suspicious substance (aluminium powder)

Note the flat top to the dish (amazing it works so well) The local town hall is not at all agreeable to strange constructions so it's invisible from outside the garden. Only about 20cms of top missing but on weak signals picture breakup can occur when certain cars pass behind the dish on the road about 20 meters away.

**T_G** · 11-09-2008

Nice one Juan! Great work, I really like it!

If you do still have the pole etc, why dont you post a picture of it if it is not too much to ask. This is really a fascinating!

Question: So when it was finished you did not move it anymore, or did you have to do some adjustments to get the best signal?

**Analoguesat** · 11-09-2008

Fabulous stuff - the ingenious dish setups made by our members really impress me every time

**Topper** · 11-09-2008

I have to confess I did more than one double take on the photograph of that dish, at first I thought, no it is a problem in the display of the photo then I thought someone must have smashed the top off,

then I read the post and see that it is made like that, absolute genius

***BombedOne*** · 12-09-2008

If anyone wants to repeat dish construction, where's reflective side is made from foil, below are several recomendations.

1. To glue such different structural materials, such as foil and concrete or fiberglass, you need phase change glue. This means epoxy and it's subtrates. Any glues based on surface tension (cyanacrilate, pva or others) won't last for long

2. To avoid bubbling and wrinkling, go to internet, and find a software called "pepakura designer". This is japanese software, you draw some 3D model in it, then it gives you flat print of it, to allow to cut out of paper and glue back into 3d. It's trialware, but will suit your needs. Draw your dish in it, and it will give you detailed print out of patches with exact dimensions of each. You need to cut out them from foil, and then glue. You'll recive minimal wrinkles using this method.

3. Using thin, kitchen use foil not reccomended. Go to hardware store, buy a thicker foil.

Juan54321 · 12-09-2008

I had to make sure the pole was pointing fairly accurately towards the satellite for maximum efficiency. After tweaking up the LNB on 28.2 I can see the dish is maybe a couple of degrees out. The construction probably weighs well over a ton. It is totally storm proof and non movable. The long focal length does allow a lot of leeway if you should want to align to other satellites though. I used a threaded bar arrangement to align the LNB.

I'm just finishing off another project (the hole in front of the dish) so I'm in a bit of a mess at the moment. I'll see if I can get to the template later and take some pics.

pride21 · 12-09-2008

hi all made 1.4mtr dish out of wood and glued ali foil on its surface it was a prime focus dish,it worked ok.

**T_G** · 12-09-2008

Originally Posted by pride21

hi all made 1.4mtr dish out of wood and glued ali foil on its surface it was a prime focus dish,it worked ok.

Pictures available??

**divibi** · 12-09-2008

Originally Posted by pride21

hi all made 1.4mtr dish out of wood and glued ali foil on its surface it was a prime focus dish,it worked ok.

Hi,

Did it perform as well as a shop bought 1.4 m pf dish? If not then to what commercial dish size would you compare it?

***BombedOne*** · 12-09-2008

I have a photos of russian home made 2 meter prime focus wooden (carcass) dish. Unfortunately, owner had no other dish to compare, since he lives in deep siberia, but he's satisfied with results, even made polar mount for it. If anyone wants, I can post these photos.

p · 12-09-2008

Originally Posted by BombedOne

. If anyone wants, I can post these photos.

yes we all want to see them!

***BombedOne*** · 12-09-2008

Now I'm thinking how to do it. Links here not allowed, but when I click "Go advanced" and then on "attachments" icon, nothing happens, so how could I post it?

**T_G** · 12-09-2008

Originally Posted by BombedOne

Now I'm thinking how to do it. Links here not allowed, but when I click "Go advanced" and then on "attachments" icon, nothing happens, so how could I post it?

You have to click on the "manage attachent" button, then a popup window opens (make sure you got popups enabled). Then you browse for the file, and press upload button. When it has finished uploading you press "submit reply". If you are not sure you can do some testing in the test forum.

If the file you choose is too large or a wrong type, you get an eerror message on top.

Try it out and let me know how it went

***BombedOne*** · 12-09-2008

Hehe, works now. It was IE problem, did it with Opera now.

***BombedOne*** · 12-09-2008

Here you can see varios manufacturing stages of that wooden dish, and also can see self made multi-focus offset dishes, which were made out of window blinds.

**divibi** · 13-09-2008

Originally Posted by BombedOne

Here you can see varios manufacturing stages of that wooden dish, and also can see self made multi-focus offset dishes, which were made out of window blinds.

Thank you so much for the pictures. I really like the wooden dish. But how rreliable are the wooden dishes? I know that wood expands and shrinks. Is that an issue, especially in Siberia? With shipping costs you mentioned maybe you'd be better off building your own dishes.

**T_G** · 13-09-2008

AMAZING! Great pictures, if anyone else got some more of the same subject please post them. I really like them home made dishes!

**Topper** · 13-09-2008

Originally Posted by BombedOne

Hehe, works now. It was IE problem, did it with Opera now.

The wood working involved in that is not small time. somebody has put a lot of time into that unless it has been produced on a cad to prototype machine. Nevertheless whatever and however it was made is still something to behold

**divibi** · 13-09-2008

Hi guys,

I have just found my old notes and I can tell you that for large KU band dishes a MILLIMETRE ACCURACY is categorically required, otherwise 'why even bother' -as the minutest of flaws will render your whole work useless and the project will end in disaster. I don't think a 240cm wooden dish could keep 1mm precision in all its dimensions, etc. I just don't know. So we live we learn; I stilll hold hopes for a super precise mould to make fibreglass dishes,though.

Also I am aware of 'spun aluminium' dishes that are said to be theorethically very accurate ( 1mm precise?) but I don't know the first thing about this process; does it involve metal smelting and furnaces

. Could you spin aluminium in your back garden?

***BombedOne*** · 13-09-2008

I'm not in Siberia

That guy is hobby plane modelist, so he has certain experience with wood processing, including making it weather resistant. No CAD controlled machinery used, he only used electric bandsaw, that's all.

divibi, you may not know, but a lot of people do at home parabolic reflectors for telescopes (of course not 2m, but 50-60cm), and they achieve micrometre accuracy, not mm

**T_G** · 13-09-2008

All I know is that my dish is not very good, i.e slightly warped because of the cheap and nasty brackets, but still I get relative good reception. If you are striving for pefection and trying to get weak signals, then pefection is needed. But you can also do it the way american car manufacurers used to do: Instead of cultivating a small sport engine they just added more volume...

It is absolutely possible to do accurate dishes from wood or concrete etc, just depends how much time you spend on it.

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Anyone tried to make BIG dish at home? If you live outside the reception footprint of a satellite and would like to, or can already receive services, post your questions or information here.

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