Plywood Dish?!

[123tim]

Back in the day (a long, long time ago, when I was still in High School.) I swear that I remember reading an article in some sort of HAM radio magazine about building a satellite antenna with only of a piece of plywood. I also swear that the plywood was used in it's flat condition. If I remember correctly, you used a jigsaw to cut circular slots in it somehow. I think that it was supposed to work on a principle similar to a Fresnel lens. I assume that it was metalized somehow, but can't really remember for certain.
Am I just remembering things that really didn't happen? Has anyone else ever heard of this?
If this isn't a hallucination, at what frequency would this have been useful for? Could it work for KU FTA?
I've searched the net, but couldn't find anything. The first sign of a true hallucination?
Thanks

 

[raydio]

Check this out -

http://www.vetrun.com/forums/showthread.php?t=1077

 

[123tim]

Thanks Jim!
That's pretty cool! I appreciate the information, and have saved it to use later. Although it uses all of the same materials, it just isn't what I was thinking of. The antenna remained pretty much a flat piece of plywood. I know now that it does exist in some form... I did find references to it last night after I logged from here.
While searching, I found a .pdf file written on the design and construction of Microwave Lenses (Not the Fresnel lens that I am looking for though). I didn't read it very closely yet, but they work in at least the 10 GHZ range. You can find it here: www.qsl.net/n1bwt/chap3.pdf This stuff may be old news to most people. If it is, I apologize.
I'm still searching for Fresnel lens information on the net.
I'm certain that none of these designs work as well as a parabolic dish. If they did, then people would be using them. None the less, I've always attracted to alternative ideas.
Getting into FTA may have been a bad thing. It's starting to spark a lot of old interest.
Now I'm thinking of building the parabolic that Jim linked me to.
Thanks again!

 

[ken2400]

I have this article at work. It may be Radio-Electronics(October 1985) BUT I would have to check on Tuesday. I have not had time to make one yet.

Back in the day (a long, long time ago, when I was still in High School.) I swear that I remember reading an article in some sort of HAM radio magazine about building a satellite antenna with only of a piece of plywood. I also swear that the plywood was used in it's flat condition. If I remember correctly, you used a jigsaw to cut circular slots in it somehow. I think that it was supposed to work on a principle similar to a Fresnel lens. I assume that it was metalized somehow, but can't really remember for certain.
Am I just remembering things that really didn't happen? Has anyone else ever heard of this?
If this isn't a hallucination, at what frequency would this have been useful for? Could it work for KU FTA?
I've searched the net, but couldn't find anything. The first sign of a true hallucination?
Thanks

 

[Stefan]

I have this article at work. It may be Radio-Electronics(October 1985) BUT I would have to check on Tuesday. I have not had time to make one yet.

Yes, I remember reading the same article and I'm fairly sure it was in Radio-Electronics. Though I don't remember the exact date, it was sometime in the eighties. Actually though they called it a "dish", it's technically just a big fresnel lens designed to work in the microwave spectrum.

I assume that it was metalized somehow, but can't really remember for certain.

I believe they painted it with either some kind of metallic or conductive paint.

 

[Katrinasucks]

It may be Radio-Electronics(October 1985) ... I have not had time to make one yet.

Sounds like my to-do list!

 

[mdovell]

That's pretty intersting that a large ku can be made..Might be a good idea to show that to some tech classes in high schools...

 

[sharris]

Just when you think that a 40" BUD experiment is pioneering. Wholly crap...lets get out the jig saw and go at' er. I'm definetely in on this one. Now just for some time to do it. Thanx for the link Rayydio

 

[ken2400]

Does anyone want the basics on how to do this? I have the article and could find some info on the web that I could post.

Just when you think that a 40" BUD experiment is pioneering. Wholly crap...lets get out the jig saw and go at' er. I'm definetely in on this one. Now just for some time to do it. Thanx for the link Rayydio

 

[Wholeshoe]

Ken2400 I would be interested in reading through that stuff. Pleas post or PM it to me.

Thanks

Wholeshoe

 

[mdovell]

This might be cool if I could convince some people at work to do it as a side project.

The only other thing I can think of that might top this would be of a wooden direct way dish....then again I heard of using a cband to create a huge wifi area..

 

[123tim]

I don't know if this would work or not (yet) but, I'd like to make the design on paper. I'm planning to using my opaque projector to project it onto the plywood in the proper proportions.

 

[ken2400]

I would start by trying to get a how power sat like 110 or 110 W

I don't know if this would work or not (yet) but, I'd like to make the design on paper. I'm planning to using my opaque projector to project it onto the plywood in the proper porportions.

 

[Alec]

I dont see any reason why a Fresnal type reflector wouldnt work, I was wondering about it myself some time back. A reflector resembling a checker board would work also, idividual squares pointing towards focal point.

 

[123tim]

Alec,

Sometimes I'm pretty dense. Could you explain how this might work? Does it work on the same principle as a Fresnel (using constructive interference)?

Thanks!