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Homemade Dish project

16K views 29 replies 15 participants last post by  rpr 
#1 ·
Has anyone made a homemade Dish either out of curiosity, necessity or boredom? I've googled the subject and seen some interesting results. Wondering if anyone here has tried it....

Reason am asking, I wouldnt mind having a 5ft mesh dish in the backyard, as the wife forbids a 6footer (currently have a 4ft off-set so whats an extra foot eh?)

Cheers, K
 
#2 ·
I wouldn't waste my time.
No way u could manufacture something to the precision required in ur garage.
 
#4 ·
The idea hit me when I was looking at an open umbrella on the floor. Google results were interesting as most where made out of foil.

In the end, when looking at a mesh dish, its only a frame and metal mesh..sure there is the science behind the angles and all, but its still just metal.

Am going to attempt one for the fun of it...it will be my winter project/passtime (my new house has a wood shop in the basement).

If anyone has any tips, suggestions or advice, it would be appreciated.

Cheers, K
 
#5 ·
It's called a parabolic dish for a reason. The science is quite well known. Somebody near here started making C-band dishes in their garage and turned it into a business. They were made of fiberglass and mesh. That was in the 1980's when C-band dishes were very expensive though.
 
#7 · (Edited)
When all around you say "you're going in the wrong direction in life"...you just might be! But, you may have fun doing so too. Keep us posted on your progress. Amateur radio ops have done this before. Go for a 10- or 12-footer to make the effort worthwhile. I have several articles on such a project from past issues of the ARRL's QST magazines: one article from 1972 by a respected authority on communications cost him about $45 back then. Can I email you the .pdf articles?
 
#8 ·
@ specialK: Are you referring to the tool 'Parabola Calculator v2' ? I downloaded it last week but have yet to use it.

@ cyberham: Email sent. thanks bud.

Took a trip to Rona last night to look at some mesh and other stuff. IIRC, someone mentioned the best would be one whereas a pen cannot fit through it. Correct?

Cheers, K
 
#10 ·
The mesh has to be less than 1/4 inch for c-band. I tip my hat for you Kraven for trying something out of the ordinary. If I had stopped uilding my weird gizmos each time someone told me it wouldn't work, I wouldn't have the creative mind that I now have.

I commend you and can't wait to hear your results whatever they might be. :)
 
#11 ·
@Skink: Would you have some pictures ?

@ Danster: thanks! I have the frame already drawn up; am concerned about the mesh though. the local store had a decent variety of mesh/wire fencing...dunno which one yet. By 1/4, do you mean tickness or width?

Cheers, K
 
#12 ·
I suspect he's referring to the size of the "diamond" mesh.
google results for "aluminum diamond mesh" and you'll get plenty hits.
some examples of various sizes:

http://www.munrocrafts.com/Wireform.html

play around with this cgi script to estimate the gain and more importantly the
3dB beamwidth of ur parobolic dish. Shoot for something with < 2 degrees 3dB BW
at C-Band to accomodate the 2 degree spacing between adjacent satellites (to mimimize interference).
You will find that the dish diameter will be the driving force for a nice tight < 2degree 3dB BW.
This is why larger dishes work better at C-Band Frequencies.

http://kb9mwr.dyndns.org/n9zia/parabolic.main.cgi
 
#13 ·
#15 ·
Tele-Satellite magazine had articles in a February 2006 magazine on designing and making your own dish, and dealt with all the formulas required. Page 56.

The same issue also dealt with using a KU dish for C Band and mentions a Toronto DX`er who did it. Page 58.
 
#16 · (Edited)
I have these articles in .pdf format if anybody wants them emailed. Send me a private message with your address.
 
#18 ·
Am curious though about the thickness of the mesh and its impact if any.
Still reading though. Am giving myself a month from today to complete this (before the snow hits)

Cheers, K
 
#19 ·
Kraven,

Yes, I believe it is quite possible to make a home made dish.

Another member (cyberham, post #7) mentioned a home made design seen in an ARRL magazine. American Radio Relay League (?)

I too have seen a home made design in a very old ARRL book. - when I was browsing in a library.

It was, I think, 12 ft dish made of 6 ft aluminum tension tubes as the frame, and mesh.
( the theory behind the design is that rods bent and held under tension form a parabolic shape ? I think that was the idea. )

The guy was using it, I think, for personal, home, Radio Astronomy hobby (!)

Yes, I've browsed (just a little) some of the calculations and theory behind satelite dish design - and it's very interesting.

You mention, you've got a 4ft dish but wanna have one a little larger? 5ft ?
I think that one (1) extra foot makes a big difference in receive area of the dish - and therefore a big difference in the receive capability of the dish.

Idea for all: What about extending an existing dish by adding an extra foot (ex. of mesh) around the outside? Possible? But that might alter the design characteristics of the existing dish some ... for sure.

Also, I have read that the higher in frequency you go, the more accurate the parabolic shape of the dish reflector has to be, and the more smooth the surface has to be.

(i.e. for C-band frequencies, the tolerances required are "do-able" by hobbyists, but if you go up in frequency, the tolerances get smaller and much harder for hobbyists to build realisticly. But higher frequencies usually require smaller dishes anyway - as the gain of the dish based on size also increases quite a bit as frequency increases - there's a formula I have seen that shows gain vs. size based on frequency)

Very interesting stuff. I am no expert - but the theory is fascinating.
 
#20 ·
I believe the home made 12 ft dish design was in this book:

(Found the details in another post of mine about trough reflectors.)

THE ARRL ANTENNA BOOK
copyright 1991 by
The American Radio Relay League
16th Edition
First Printing
ISBN: 0-87259-206-5

There are probably other versions and printings of the ARRL Antenna book out there. That's just the exact one I looked at in the library.

I imagined building a dish out of grey or black fibreglass, rectangular "fence spreader rods" as the tension rod frame, and some sort of mesh.
 
#22 ·
Update: Project is on hold for a while... the GF delivered 6 weeks early, so most of my free time is gone for the next 18 years.

Using all the articles emailed (thanks guys) and a parabolic calculator, the frame is done. The diameter of just under 7 feet (very light but sturdy) and can be taken apart in 3 pieces.

Next step is to apply the reflective material. Ive already scouted the local hardware stores and found some interesting options. If anyone seens anything to would work...(canadian tire, rona, reno, home hardware etc..) please let me know.

Due to its light weight, mounting shouldnt be a problem. How to apply a motor though is beyond me at this point since I need a better understanding of prime focus/off-set/allignments etc....

Cheers, K
 
#24 ·
When I first left on paternity leave, I figured with 2 months off I'd have all these free time in the world to work on projects and get things done around the house....finnaly I didnt get anything accomplished!

This weekend, weather permitting, am thinking of setting up the dish outside for a test. Regarding the reflectors, would Alluminum tape make a good reflective surface? I have boxes of it at home and it would be easy to complete it.

Cheers, K
 
#26 ·
Wooden Satellite Dishes have been made

I've been looking into building a 1.2-1.5m offset dish and I found that some guys in Australia have built 1.0-1.8m prime focus satellite dishes using either wood and aluminum foil-covered plywood or aluminum rod and aluminum mesh. There are a couple Canadian builders around pages 17-19. Some theory, a lot of practical info. The moderator glued aluminum foil on plywood and even though there were some small wrinkles it didn't hamper reception too much.

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

Separate thread, same site, in aluminum rod and aluminum mesh:
http://www.vetrun.net/forums/showthread.php?t=5469

And a guy in the Caribbean made a wooden one (a long thread on a UK site, wanders a bit, the link goes to his construction pics):
http://www.satellites.co.uk/forums/fringe-reception-general/134500-anyone-tried-make-big-dish-home-27.html#post835448

I found aluminum flashing at a local big box home building centre (not HD), 10 inches x 50 feet $22.99 Cdn., 14 inches x 50 feet $30.99. Their plywood is cheaper than the others too.

After C-Band satellites... cheaper to build than ship and I like to tinker. I've made an OTA antenna that gets CBC and TVO from in my attic, the other TV stations might be too far away. My TV Fool results don't look good. That's why I'm looking at FTA too.

David
 
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