Paint Cantenna

acidrayne · 05-22-2002

So ... I have been searching the forums for a while now and although I have found many matches for can and antenna I have found nothing about a Paint Cantenna.

I was just curious if anyone had thought of or had experience with this. If I did miss a forum about this if someone could post that link that would be great.

Otherwise any information like websites or just general gain and instructions on how to make one would be appreciated.

Thanks

Thorn · 05-22-2002

Quote:

Originally posted by acidrayne
So ... Paint Cantenna.

This probably isn't what you want, but:

The only "Paint Cantenna" that I know of was a HeathKit from the 1970's. It was a dummy load for testing transmitters.

The Cantenna was a one gallon paint can, which you filled with transformer oil. There was an RF port on the top (SO-239) and a RCA jack for signal output, so you could see the signal on a scope.

The SO-239 was connected to a huge resistor, which sat in the oil. If I remember correctly, you could dump up to 1kW (yup 1kW!) into this thing before the oil would start to boil. There was even a small pressure relief valve on top, in case you did manage to get the oil boiling.

I had one a few years ago, which I gave away, because I wasn't playing with my radios at the time. dammit...

lincomatic · 05-22-2002

are you referring to this?

http://www.oreillynet.com/cs/user/view/wlg/1124
http://www.turnpoint.net/wireless/cantennahowto.html

i've built one...it works great. very directional. it's handy for
pinpointing the location of an AP. the performance is better than the pringles, and it's a lot easier to build, too.

the only problem was all the beans i had to eat to get the can

gcrocker · 05-22-2002

This page has a calculator for figuring out how effective a given can size might be for 2.4GHz:

http://www.turnpoint.net/wireless/cantennahowto.html

Basically, a paint can would suck for a cantenna. About 3.5" diameter is ideal.

This might be closer to the right size for the paint can (though the height needs to be cut to 32mm), and is the best directional plan I've seen online so far:

http://www.saunalahti.fi/~elepal/antenna1.html

-glenn

fordem · 05-22-2002

Quote:

Originally posted by gcrocker
About 3.5" diameter is ideal

Hmmm - 3.5" - I've got some 1 pint cans of paint

lincomatic · 05-22-2002

this guy thinks the feed hole should be 3/8lamba away from the end.

http://www.radio-active.net.au/web/80211/pringles.html

NOTE: he calls it a pringles antenna but he's really talking about the tin can antenna...

ZipperSeven · 05-22-2002

Fordem- 1 pint cans are around the right diameter, but how tall are they. From what I've seen (but I'm no expert, I just ran the numbers) the can has to be close to double the length of the diamter of the can, which is hard to find. The pirouline can was the closest can i could find locally. The site at the bottom of gcrocker's post was the one that I used.

Thorn · 05-23-2002

From this month's WIRED magazine:

gcrocker · 05-23-2002

Those Guinness cans might be good.

-glenn

vdocam · 05-27-2002

about that Wired magazine antenna...

apparently they suggest that you solder your copper driven element right to your pigtail? are they nuts? i guess if you never intend to use any other antennas with your pigtail you could do this, but it seems wasteful to me. per the o'reilly article, it seems better to use an orinoco to male N adapter, and then put a female N connector on the can, to plug into.

ZipperSeven · 05-27-2002

The antenna that syko jester and I built is built exactly that way, vdocam. We have a chassis mount female N jack with the copper element soldered to it. Actually, in this pic, it's shown about to be mounted to the piro-cantenna, but is normally used in the pringles-cantenna.

Also, while I subscribe to Wired and often find the articles informative and amusing, I think that their attemp to show this as if it was their idea, or that they stumbled (_pardon, not meant as a pun_) on to something 'new', is kind of cheesy. I mean, this idea has been circulating around for almost a year. The O'reilly article was posted June last year, and was adopted from an idea on Andrew Clapps' site, which is of an indeterminate age. Anyway, excuse the rant, I just find sometimes that corporate entities need to take more initiative if they expect to take credit for mainstream ideas, instead of borrowing from others (cough, micro$oft).

vdocam · 05-27-2002

I agree with you on Wired... I got my subscription for free, and it's good for some entertainment once in a while.

I'm looking forward to playing with the can antenna design. I already have my Orinoco pigtail, and I ordered a few panel mount female-N connectors which should arrive later this week. I guess I need to start looking for a good can to experiment with. The javascript calculator on http://www.turnpoint.net/wireless/cantennahowto.html looks like it should be a big help in figuring out where to drill.

Thorn · 05-28-2002

I, too, received my subscription of Wired for free, otherwise I never would get it. When Maximum Linux went under, the publishers sent me this very poor substitute rather than refund my money.

I've always considered Wired to be the USA Today of the digital world. Big on flashy graphics and other eye candy. Low on real (read: technical) content. You will certainly look cool reading it to anyone outside, but you are probably not learning anything real useful.

As far as their antenna instruction I posted: IMHO it has enough information to be useful if you already know this stuff (it has the correct dimensions), but as vdocam pointed out, the instructions are poor. I posted it more for "hey! look at this" than I expected anyone to actually build it from these instructions alone.

Cheers,

ZipperSeven · 05-28-2002

Please do not get me wrong, I was not meaning my post as a personal jab towards you, Thorn, rather as a personal commentary on the magazine itself. I agree wholeheartedly with you.

Thorn · 05-28-2002

ZipperSeven, I didn't take it personally.

I think most people who read it, feel about the same way. It's BIG, it's BRIGHT, it's IN YOUR FACE, it's COOL. And it's lack of real technical content is readily apparent after about 1 page. It's a pity really. Maximum Linux was so much better.

<sniff>

But damn, I look cool reading it.

Cheers,

05-22-2002	#1 (permalink)
acidrayne Slacker Stumbler Join Date: May 2002 Location: Kansas Posts: 476	Paint Cantenna So ... I have been searching the forums for a while now and although I have found many matches for can and antenna I have found nothing about a Paint Cantenna. I was just curious if anyone had thought of or had experience with this. If I did miss a forum about this if someone could post that link that would be great. Otherwise any information like websites or just general gain and instructions on how to make one would be appreciated. Thanks __________________ Rayne

05-22-2002	#3 (permalink)
lincomatic Squaaawk! WiFi! WiFi! Join Date: Apr 2002 Location: Tinsel Town Posts: 1,682	not a paint can, but... are you referring to this? http://www.oreillynet.com/cs/user/view/wlg/1124 http://www.turnpoint.net/wireless/cantennahowto.html i've built one...it works great. very directional. it's handy for pinpointing the location of an AP. the performance is better than the pringles, and it's a lot easier to build, too. the only problem was all the beans i had to eat to get the can __________________ ~lincomatic

05-22-2002	#6 (permalink)
lincomatic Squaaawk! WiFi! WiFi! Join Date: Apr 2002 Location: Tinsel Town Posts: 1,682	this guy thinks the feed hole should be 3/8lamba away from the end. http://www.radio-active.net.au/web/80211/pringles.html NOTE: he calls it a pringles antenna but he's really talking about the tin can antenna... __________________ ~lincomatic

05-27-2002	#10 (permalink)
vdocam Registered Member Join Date: May 2002 Posts: 6	wired magazine cantenna about that Wired magazine antenna... apparently they suggest that you solder your copper driven element right to your pigtail? are they nuts? i guess if you never intend to use any other antennas with your pigtail you could do this, but it seems wasteful to me. per the o'reilly article, it seems better to use an orinoco to male N adapter, and then put a female N connector on the can, to plug into.

05-27-2002	#12 (permalink)
vdocam Registered Member Join Date: May 2002 Posts: 6	cantenna I agree with you on Wired... I got my subscription for free, and it's good for some entertainment once in a while. I'm looking forward to playing with the can antenna design. I already have my Orinoco pigtail, and I ordered a few panel mount female-N connectors which should arrive later this week. I guess I need to start looking for a good can to experiment with. The javascript calculator on http://www.turnpoint.net/wireless/cantennahowto.html looks like it should be a big help in figuring out where to drill.

05-22-2002	#4 (permalink)
gcrocker Registered Member Join Date: May 2002 Posts: 31	This page has a calculator for figuring out how effective a given can size might be for 2.4GHz: http://www.turnpoint.net/wireless/cantennahowto.html Basically, a paint can would suck for a cantenna. About 3.5" diameter is ideal. This might be closer to the right size for the paint can (though the height needs to be cut to 32mm), and is the best directional plan I've seen online so far: http://www.saunalahti.fi/~elepal/antenna1.html -glenn

05-23-2002	#9 (permalink)
gcrocker Registered Member Join Date: May 2002 Posts: 31	Those Guinness cans might be good. -glenn

05-28-2002	#13 (permalink)
Thorn Did you do the math? Join Date: Apr 2002 Location: Villa Straylight Posts: 10,361	I, too, received my subscription of Wired for free, otherwise I never would get it. When Maximum Linux went under, the publishers sent me this very poor substitute rather than refund my money. I've always considered Wired to be the USA Today of the digital world. Big on flashy graphics and other eye candy. Low on real (read: technical) content. You will certainly look cool reading it to anyone outside, but you are probably not learning anything real useful. As far as their antenna instruction I posted: IMHO it has enough information to be useful if you already know this stuff (it has the correct dimensions), but as vdocam pointed out, the instructions are poor. I posted it more for "hey! look at this" than I expected anyone to actually build it from these instructions alone. Cheers, __________________ Thorn "Read Altas Shrugged. Compare it to today. Repeat as necessary"

05-28-2002	#15 (permalink)
Thorn Did you do the math? Join Date: Apr 2002 Location: Villa Straylight Posts: 10,361	ZipperSeven, I didn't take it personally. I think most people who read it, feel about the same way. It's BIG, it's BRIGHT, it's IN YOUR FACE, it's COOL. And it's lack of real technical content is readily apparent after about 1 page. It's a pity really. *Maximum Linux* was so much better. <sniff> But damn, I look cool reading it. Cheers, __________________ Thorn "Read Altas Shrugged. Compare it to today. Repeat as necessary"

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