In this pictorial I'm showing you how to make a 16dBi very powerful wifi antenna for under 10 dollars. I've already posted a movie about this but a lot of people asked or a pictorial, so I've made another one so I could make pictures.

Step 1: Materials Needed

This picture shows you what you need.

A 12x12cm brass, copper or tinned metal plate, a BNC chassis connector, a BNC cable connector, 35mm thick PE or styrofoam (can also be thicker) and some 1.5mm2 single core wire. This stuff is used in the netherlands in 220V in house cabling.

Other possible materials:
I can imagine that people want to use other materials, like a pipe to mount the antenna wire on. If you could get a pipe with roughly a 35mm diameter, you can use that IF the material is good for radiowaves. There is a very simple way to find out. Place a piece of styrofoam in your microwave, together with a piece of the material you want to use. Turn on the microwave for 30 seconds. Stop the microwave immedeately if you see the other material melt. Now check out how warm the other material is, if it's not warmer, or a little warmer than the styrofoam, you have found suitable material, if it has melted or is very hot,that you're dealing with lossy material which absorbes microwave radiation and turns it into heat, this material is useless for making high performance antenna's. This trick works so well because the WIFI band is at 2.45GHz and microwaves also radiate at that frequency, so it's a perfect test. Some very good materials are PE tubes, teflon tubes (if you can afford them) and PolyProlylene tubes.
<p>This is circular polirised? wouldnt the antenna on the modem and pc need to be changed to circular porized aswell?</p>
<p>When you attempt to transmit with a vertical antenna and receive with a horizontal antenna via line of sight, there is about a 30db polarization mismatch loss. The circular polarization on one of the antennas takes care of that. It has almost equal polarization in both horizontal and vertical planes, so the other antenna can be either V, H, or Circ. The measure of the quality of that circular polarization is called axial ratio. Satellites tend to &quot;tumble&quot; and their vertical antennas can be either vertical, horizontal or &quot;in between&quot;, earth stations tend to use circular polarized antennas to provide optimum service.</p><p>Dick</p>
I made this antenna. I connected it with about 4' of TV cable and had no improvement altogether. Then I changed TV Cable to CAT 5e (by cutting the connectors off and soldering one end to antenna and another to my card's external antenna. That action killed the signal altogether and now I'm w/o Wi-Fi - thus w/o internet!
<p>my friend, you MUST ONLY use a coax feed line thats rated at 50 ohms. TV cable (rg-59 or rg-6 etc) is rated at 75 ohm. CAT 5e? different types of data cables have ratings of 300ohm, 600ohm &amp; some at 150ohm. but cat 5-5e &amp; cat6-6a are typically considered 100ohm. however, (real world) a UTP pair will give you less than 10ohms for approx 100m. either way, those options were destined to failure. The use of CAT5e to feed an antenna at 2400mhz+ probably resulted in nearly ZERO emission from the antenna at all. Instead, the CAT5e became the antenna itself. but was incredibly mismatched, (a) resistance of 10ohms instead of 50ohms &amp; (b) length of wire certainly wasnt tuned to a 2.4Ghz wavelength.This probably caused all the RF energy to build severe standing-wave &amp; reflect everything back into the output circuit..... POP! [smoke exits device, etc.] </p><p>dont be discouraged. i've done worse to a $300,000 FM transmitter (i didnt really like that job anyway. but the competing stations LOVED me )</p><p>keep experimenting (but read first),</p><p>CHEERS!</p>
<p>&quot;but cat 5-5e &amp; cat6-6a are typically considered 100ohm. however, (real world) a UTP pair will give you less than 10ohms for approx 100m&quot; <br><br>Cat 5-5e, at 100 mhz is rated at 100 ohms impedance (different than pure resistance &lt;10 ohm/100m ) Note that impedance results from inductive and capacitive reactance at a particular frequency versus resistance that depends length on cross section. Although, at high frequencies, skin effect can effectively reduce a conductors cross section, but impedence is still different than resistance. </p>
<p>i burned out at least 3 cards before learning always ground yourself to something via speaker wire or buy one at radio shack $5. your wifi card is not built to last. try again or give up . done correctly this antenna is the preferred design for wardriving. in moms basement a simple dipole with a parabolic reflector cant be beat.. . </p>
how did you write this comment without internet?
Good call haha<br>but yer friends house<br>also amazing project but how well will this work through 4ft of stone and a distance of around 30ft? (i have a art studio with no phone socket in case your wondering)
He probably went to a friends house or a library =P<br/>
You need to use coax cable that is rated for WIFI. At the frequency that WIFI operates (2.4 GHz), the signal loss is very high, and the longer the cable between the antenna and the wireless card, the worse the signal loss. Cable that is rated for WIFI is more expensive, but it's the only real way you'll get the signal from your antenna to the wireless card. It's worth the money spent.
just a misc. comment... lol wat kinda accent is that guy in vid have?
<p>As he is receiving a signal from Pijnacker, it is most likely the Netherlands so I guess Dutch.<br>His Antenna can't be that good that he is receiving Pijnacker all the way in Wisconsin</p>
I think they talk like that in Wisconsin
&quot; This stuff is used in the netherlands in 220V in house cabling. &quot;<br> Dutch maybe ?
<p>id like to see how you got 16dbi .. its possible.. aluminium siding reflects . this is a good design in dense urban areas . easy 8-12 dbi over 1/4 wave. dipole . increased signal with reflector made from aluminum screen and patience.. </p>
<p>Brilliant! Also beautifully sorted (Microwave testing!) and photographed....</p><p>I don't need one at the moment, but if ever I do.....</p><p>One question, do I need two of these, one for each direction, or is one enough?</p><p>Many thanks for sharing</p><p>Regards</p><p>Andy</p>
<p>There are many low cost usb wifi adapters with an external antenna connector.</p><p>I would mount one directly to the helical antenna and use a good grade usb cable to computer.</p>
<p>will it work as a transmitter antenna connected instead of a factory-made wifi router antenna? </p>
Nice antenna - it works! If you're not happy with using some LMR400 cable, I certainly suggest mounting the wi fi adapter right at the base of the helix.&nbsp; For another perspective look at <a href="http://www.ab9il.net/wlan-projects/wifi3A.html" rel="nofollow">http://www.ab9il.net/wlan-projects/wifi3A.html</a> and see it will work okay mounted that way.&nbsp; Also, the wire on PVC works and so does copper foil tape.&nbsp; Delicate, though.
New to all this. Trying to recieve a signal aboout 250 feet from my sailboat. Trying to find the video.....?<br><br>Thanks
He said 'insulation'...<br>
can I used the female RPA connector from the wifi card?I was thinking that it might boost the signal if I will derectly connected the wifi card from the antenna rather than using a cable Thanks<br>
fiber glass works well i have had several antennas made out of it
Is it good to emit a signal with an Access Point or, is it only to terminals???
Nice, Try to track down LMR400 or even LMR100 on a budget for the cable, as it is designed for microwave use. Keep in mind that good cable can be a bit expensive, though it will cut down signal LOSS at 2.4ghz frequencies. Wrong cable can reduce the signal at the point of a standard antenna, or even lower. <br><br>here is another alternative, but the cable really needs to be replaced with decent cable. http://www.dealextreme.com/p/2-4ghz-8dbi-sma-high-gain-dish-directional-antenna-for-wifi-wireless-network-2400-2483mhz-32023
I'm going to experiment with connecting this to an internal laptop wi-fi card at the point where the internal antenna connects - probably could piggy-back it - I'm afraid of blowing one up, but I have a couple spare wi-fi cards from dismantled laptops... I'll test this on a spare and see what happens and post my results later... although it will be a while...
Is this correct? 120mm of the square's side is equal to the wave length, 30mm spacing between wire turns is equal to 1/4 wave length and the diameter of the pipe again 1/4 wave length.<br>What I'm trying to do is to adapt your design to 2.1GHz(UMTS).
Well .. I asked a friend of mine (Google) and he said that this type of antenna is called &quot;helix antenna&quot;. Also he said that reflector should be &gt;3/4 wave length, helix spacing is indeed 1/4 wave length and helix diameter is 1/pi wave length(in other word the circumference of one helix turn has to be equal to wave length).
Is this antenna adapted to 50ohm? Helical antennas have around 140ohm input impedance, but is styrofoam acting like an dielectric?
Oh .. you explained that in step 5, you did this by flattening 30mm of the spiral above ground. How much will I have to flatten for 2.1 GHz ?
Yep .. after some hard search, 1/4 wave length again. Now I can build it.
Hi, I just wondered if this could be made with laminated corrugated cardboard instead of foam.
No reason no to. Just nothing conductive is the main thing.
How does it perform? 100% SS is good so long as the signal quality is there to match, my digital tv recieves 25% signal strength but the signal quality is still 100%
<strong>Wonderful, but the wire thickness is 1.5mmsquare or 1.5mm diameter? please clear me</strong><br/>also can a PCB be used instead of copper plate??<strong></strong><br/>
if you use pcb's be a good idea to not have it aeounf people and wear the full safetyset up. unless you meant pvc. kidding ya
Err, sorry. I just realized the hypotenuse of 3.5*3.5 is 4.9 cm. A little more. Anyone know a good substitute for foam?
Oops again LOL, google messed up my metric conversion. .5in is not 3.81 cm.
I am building this one again. <br>I wanted a way to mount the plate &amp; aim it <br>a refinement I opted for is to put a .060&quot; aluminum 2&quot;x12&quot; bracket in between the Copper plate &amp; the N-50 connector. drilled &amp; used a countersink bit to bed it in till solidly placed. <br> bend the ends 90 degrees. drill holes as needed &amp; mount. <br> I am planning on getting a Students gooseneck lamp &amp; mounting my antenna in place of the lamp. <br>this extra metal has a benifit of keeping the soldering nub/hub down below the surface. <br>just trimmed the soldered part down to 1 mm high. <br>Slim49
Come on People, <br>I built this antenna last year &quot;from&quot; the video. had to replay a few times! :-) <br>but got it in 1st pass.I used 14gu. copper I stripped out of some Duplex house wiring. <br>a packing /shipping company gave me teh foam, I had to put an extra piece 1/2 length underneath to support it. <br>I used the Copper clad &quot;ROOf&quot; material you see on the finer houses. <br>the Roofing co. gave me a free scrap. I have made 5 antennas from it! still plenty left. <br> it is a super Hi-gain antenna!! <br>it is circular polorized, so what!! <br>it gets the signals in, for My rural buddy, it is THE only one of the 4 types I built that works. its a complete wave length antenna, I think that is alot of its sucess. <br>it is HIGHLY directional!! and I mean 1/2 degrees can make or break you. <br>easier to use than the 15 element Yagi. that is Sick directional, though easier to DIY. <br>I have been meaning to make of this conical Foam antenna for myself. <br>I tip my hat Dude. <br>Steve
Perhaps I and others are impatient to get answers or replies. most readings of instructions generally easy and simple to understand and follow through. Is this in the U.S.? the tinkerer has an accent speaks fast like watching time. I live in Ontario, Canada. Most of these items not available in stores. I might try something else or just give up and take this as...spam. my email is artistonhpvs@fidohiptop.ca thank U
Honestly, I'm from the U.S. and I understood it very easily. BNC connectors are widely available from parts houses, the copper wire is the hardest part to get - but if you scavenge you can find it free in junked appliances. Otherwise, try a hardware store. The plate of thin metal is easily acquired from hobby shops.
We all appreciate this idea and well-done informational video. Very easy to follow. I shall build one for my friend who lives in the city but for myself, I live in the forest seven miles from a signal, I shall continue struggling with the giant C-band parabolic dish hoping to gather just enough to make it work. Thanks again and keep up the good work.
Fascinating. How do you go about using your C-Band antenna as a WiFi receiving device. Would make a great instructable.
C-Band 'dish' antennas are a combination of a reflective dish that is not band dependent and an LNB that actually receives the c-band signal and converts it into a signal that RG-8 is capable of handling with acceptable loss characteristics. The lnb is usually located in the canister suspended out in front of the dish. To convert to WiFi, you need to place the antenna for the wifi device at the focus in place of the lnb. This is the same technique used to convert the dish network and other smaller satellite dishes into wifi signal boosters. The primary concern would be that you may exceed allowable gain restrictions the FCC has imposed on wifi transceivers.
Rusty That far away from a wifi with no change in your transceiver power output, you will not bust the FCC limit which if you check Part 15 allows up to 100mw in the 2.4 GHz band at the source (your antenna). Most devices, unless you hack them for a power setting are well within the output specs required. Remember. It not the gain your antenna has, it is the power output at that antenna. Good luck with your project and wait for the FCC to knock on your door to worry about the law. Raving Apache

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