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Cardboard WiFi Antenna Upgrade
An anonymous reader writes "A British company called Tritium is marketing a piece of cardboard with metal foil on one side. You order it for under US$25, shipping included, and you get a flat envelope with the cardboard. Cut it out, shape it into a parabola and snap it into the little stand. Then slip it over your current antenna. It is advertised to extend the range of your current antenna by 2 to 3 times. See their website for more information on the cleverly named Tritium Flatenna."
Or you could just go here and make your own with stuff in your house for under $1.
These would probably put you over the legal limit, if you get more than ~5dBi out of them, which you should. Most cheap consumer gear is 15dBm, so 15+5=20dBm=100mW
That was fast. Less than 5 posts and the machine is melted.
9 7.php
w w.tritium.co.uk/
Well here's a press release on the product. I like the part about it "vaguely resembling a Klingon space ship".
Check it here: http://www.prweb.com/releases/2004/6/prwebxml1350
Oh and of course the Google cache of the melted tritium.co.uk box: http://66.102.7.104/search?q=cache:TSbW7tvLA14J:w
It looks to me as if 15 minutes with graph paper, scissors and glue (together with a bit of card stock and foil) would give you the same thing, without waiting on the snailmail, and without the $25 U.S.
By the way, the site I link to says 9.99 pounds, which should be a bit less than $25.
See what I've been reading.
I have some tritium keychains and some watches with tritium in them. The mesuarable dosage that you get from it is nominal compared to background radiation. IE the difference in background radiation exposure between someone living in the mountains and someone living at sea level is greater than the difference in exposure carrying a small amount of tritium with a phosphor coating. You just don't want to eat the stuff. With a half life of about 15 years, tritium will hang around in your body quite a while.
The main difference here is that there have been many studies on radiation exposure over both short term and long term durations. There have been far fewer studies on the effects of high frequency, low energy RF. When you consider what high frequency, high energy RF and even low frequency high energy RF can do to the human body, it sure makes you wonder if this stuff is safe anyway.
People this paranoid, however, are definately the target market for this kind of antenna.
To me, the whole thing reeks a little on the surface of ads proclaiming something 'it's like attaching a four foot antenna to your cell phone!, though the obvious benefit here is that it's an antenna tuned to a specific frequency designed to make an omnidirectional antenna a little more directional. Still when you can make it for about $1 using a ruler, some foil, and some scissors you have to wonder why they are even bothering.
This is NOT an upgrade for your antenna. This doesn't increase gain, it just takes it from the back and adds to the front. The good thing about this method is it doesn't require you to modify your original antenna, so you don't have to worry about breaking FCC regulations on all equipment being certified. Apart from that, they are selling for $25 something which I created for free out of household items. Check here for more info on how to do it yourself (took me all of 30 minutes the first time).
But again, I want to state this isn't an upgrade, your antenna isn't any more powerful, you're just taking power from the back and shooting it forward, so if you need omnidirectional signal this isn't for you. It can however, increase a dirctional link, but so can a pringles yagi directional, and that's still cheaper than this. Forget about this company and just make your own, it's simple, fun, and cheap, and gives you more of a choice in what material you want to use.
Everyone is entitled to their own opinion. It's just that yours is stupid.
I think the stuff reflects the microwaves back through the food, to effectively double the cooking speed.
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Yes, tritium is a very low power beta emitter. I occasionally work with the stuff, for detecting various biological macromolecules. It takes weeks for the stuff to make an image on photographic film, that's in direct contact with the gel, and soaked in fluorographic enhancer. Our required dosimeters can't even detect the stuff, nor can a geiger counter. We still do periodic wipes and scintillation count them though. It's emissions wont get through your skin. Really the only risk is if you quaff a flask of the stuff.
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Or phosphor coat it for that matter? Tritium is a Hydrogen isotope.
You can disolve tritium in a phospor liquid. Tritium is usually used in compounds or molecules that have been 'tritiated'. Like tritiated water, tritiated thymidine, etc.
Set the kind of post to "HTML Formatted", using the little menu in the lower right. Then wrap HTML markup around it:
<a href="http://www.foo.com/"> Text that you want highlighted </a>
Fractenna is actually a pretty interesting-looking link. Thanks.
WWJD for a Klondike Bar?
And you are correct, gain antennas can not 'create' or 'amplify' energy (for that, you'd need an amplifier, duh), they only take what energy is fed into them and direct it in a prefered direction at the expense of other directions. Consider the common yagi (or Yagi-Uda for the purists). Great gain forward, almost none to the sides, limited to the rear.
This cardboard reflector is doing about the same idea - but by reflection rather than refraction. One possible caveat - depending on the distances from radiator to reflector, you can get phase problems. Get the spacing wrong and you can all but cancel out your own signal - or make it unusuable.
Senior NCO in the fight against entropy. I've seen things, man. Things no one should have to see.....
I think the stuff reflects the microwaves back through the food, to effectively double the cooking speed.
No, the previous poster had it right.
Your basic microwave heats the food where there's water or resistive material (like carbon). So it tends to make crispy materia soggy (by "steaming" it with the water evaporated from the wet places). And if you heat it long enough to dry it out, some spots heat enough to become burned - at which point they absorb more microwaves and become MORE burned - in a positive feedback that makes spotty burns rather than a crispy crust.
The material is very thinly coated with metal and quite resistive. So it absorbs a portion of the microwaves and becomes very hot. The infrared is used to crisp the surface of the material, like a broiler would.
Getting the packaging balanced - so the food is thawed, frozen, and crisped properly in the oven - takes some work. (Resistive cookware is available for do-it-yourselfers who want to broil in a microwave oven.)
Such resistive packaging would make a rotten reflector. It's more like a "stealth" coating on an aircraft than a microwave mirror. (It might be useful, though, to make a microwave absorbing wall between your antenna and a nearby interference source.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Or you could just buy a Cantenna. It's based on the pringles-can antenna, but it's bigger, better, weather-proofed, and takes a lot of the hassle out of making an antenna out of a pringles can. Not to mention the fact it's better.
Cost:
Chicken wire $1 (from hardware store)
styrofoam as a base $0 (free from greengrocer)
Cable ties (to hold it together): $1
Gain should be at least 6dB
Parent said "This doesn't increase gain, it just takes it from the back and adds to the front." But this is the definition of gain from an antenna: it alwas is about taking ot from the back and adding it to the front. An antenna, which is just some passive materials, can never add any power!
Depends on the strength of the beta.
Tritium's beta has a mean of 6KeV... you need a beta with an energy of at least 70KeV to penetrate the dead layer of cells in your skin.