Pringles....

Pringles....

Postby IronNet » Mon Jan 13, 2003 7:59 am

Iam sitting here and doing some math with my ARRL-handbook. The Pringles-can that is a mix of a waveguide and nonconnected yagi don't match up with the math. The diameter is to small to work in the 2.48GHz span. So why does it work?? Does anyone know?? I made a Pringles-antenna and made serious measurements on it and it showed that the antenna is not good. It showed that the Pringles only came up to 2dBi gain in the front loob.

Ok Pringles don't work but how should a cheap good antenna look like?? I made a standard waveguide with a diameter of 85mm and made the same serious measurements on this antenna...and woops the gain was 8dBi.

The thing I would like to say with this is that if you would like to make a good antenna check the theori first...like the ARRL-handbook.
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Postby Thorn » Mon Jan 13, 2003 8:21 am

Anyone who is serious about antenna design should get the ARRL book. Search the site, and you'll see this actually gets recommended often.

As to the infamous Pringle's antenna, you are correct. It is the wrong diameter. Search the O'Reilly web site, and you will find that it was based on another antenna, that was properly designed. The designer of the Pringle's (Rob Flickenger) can did not have the correct size can (a nut can, if I recall) so he tried a Pringles, and it worked well enough for him to publish the results.

So why it does work at all? It isn't a wave guide, contrary to what some have said. The "foil" coating apparently is not heavy enough to produce a guide function. As you have said, it is actually closer to an enclosed yagi than anything else. Depending on a number of factors, including contruction skill and pure luck, people have reported anywhere from 2 to 12dB (dBi ;).)

You must remember however, that many people who are reporting such gains are using software graphs such as the one included as part of NetStumbler to measure the results. Most do not have access to use, and may not be aware of the existence, of instuments to do such things. So the actual results, as measured on a spectum analyzer, might be different than the reported values.
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Postby peekitty » Mon Jan 13, 2003 12:56 pm

Well said, Thorn. That should be made a sticky, despite what all the chip-munchers might say...
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Link?

Postby L8Nighter » Mon Jan 13, 2003 3:40 pm

After reading alot of posts it seems the tin can design would be better then a pringles can for directional. Would you guys mind providing a link with instructions to the best but cheapest directional anntenna that you have found while surfing around? Just something to hold out a car window.
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Postby peekitty » Mon Jan 13, 2003 3:55 pm

Lincomatic's antenna page has plenty of great info.
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Thanks

Postby L8Nighter » Mon Jan 13, 2003 6:43 pm

Thanks :)
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Postby Thorn » Mon Jan 13, 2003 9:39 pm

Originally posted by peekitty
Well said, Thorn. That should be made a sticky, despite what all the chip-munchers might say...

Thanks peekitty. Truth be told, I constructed one just after R. Flickenger's article came out back just to see if it could be done as easily as claimed. It can be done, and you can get fair directionality from one and some gain, if you are careful in your technique. However, I've also built a few ham antennae in my time, so this wasn't something totally new. Just a new band.

What I think is the really interesting part, is that how this has created a whole movement. No doubt sociology types and advertisers will be studying it for years: Think about it. Take a popular snack with a national/worldwide presense, and convert its packaging into a low-end yet workable device for use an technology which is just hitting its stride with the public. Something that has got absolutely nothing to do with the snack. Then the press runs with it. Suddenly, everyone who has ever had any contact with computer tech in the last couple of years knows what you're talking about when you say "Pringle's Can." Pringles could not have tied themselves to this kind of world of mouth advertising if they tried. They ought to do something for Flickenger, he's probably singlehandedly boosted they're sales for the last two years.
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Postby c0nv3r9 » Tue Jan 14, 2003 9:09 am

Wouldn't it be funny if the size of the can, just, randomly changed... or if the inner foil lining were slightly thickened

Pringles, the preferred potato chip of 802.11b
He shall recount his worthies: they shall stumble in their walk; they shall make haste to the wall thereof, and the defence shall be prepared.
-- Nahum 2:5, The Holy Bible, KJV
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Waveguide for real

Postby IronNet » Thu Jan 16, 2003 6:50 am

I have just started building a "real" waveguide antenna with square elements. I will post later and tell you all how it went.

Iam sure of that I can build an antenna that is better then the commersial ones for 1/10 of the price and just as reliable.

We will see.....
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Re: Waveguide for real

Postby peekitty » Thu Jan 16, 2003 8:18 am

Originally posted by IronNet
I have just started building a "real" waveguide antenna with square elements. I will post later and tell you all how it went......
I didn't know a waveguide normally has elements. Sound like you're describing a Yagi, am I mistaken?
Iam sure of that I can build an antenna that is better then the commersial ones for 1/10 of the price and just as reliable. We will see.....
No argument there.
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Re: Re: Waveguide for real

Postby IronNet » Thu Jan 16, 2003 10:17 pm

[quote]Originally posted by peekitty
[B]I didn't know a waveguide normally has elements. Sound like you're describing a Yagi, am I mistaken?

I mean instead of a circular can i will use a square one, sorry for the misspelling.
//IronNet
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