Introduction: Easy to Build WIFI 2.4GHz Yagi Antenna

Picture of Easy to Build WIFI 2.4GHz Yagi Antenna


This antenna will extend the range of your WiFi or 2.4GHz devices (like surveillance cameras) into many miles and kilometers. A yagi antenna is basically a telescope for radio waves. I tired the pringle can antenna and the Yagi beats it hands down in performance.

Step 1: What You Need

Picture of What You Need


This is an absolutely easy project.

You need an ink jet printer/ Computer
Popsicle sticks
White glue
Crazy glue
Big paper clips (you could use any stiff solid metal wire instead)
USB WIFI, preferably with an antenna extension OR a 2.4 GHz device
soldering iron and lead
Sanding papers
Scissors
Pliers or preferably a nibbler (see photo below, available at radio shack)
a metric ruler with millimeters or a metric caliper.

Step 2: Building Overview

Picture of Building Overview


The building steps are simple:

1. Print out the scaled Yagi antenna template* (download from next step).
2. Trim paper clips to size and glue them to the template.
3. Use Popsicle sticks to build the antenna's backbone and hold it together.
4. Connect the USB device to the antenna.

*I used a Yagi modeler java applet to generate the diagram. This modeler applet is found on many websites (google "yagi modeler") and its owner is W9CF.

The modeler gives a diagram and the elements' lengths and position. I carefully scaled the diagram and turned it into a template in order to make the building process easy.

You can visit AB9IL awesome website  to get more details on using the modeler for this 15 element Yagi and other fine antenna projects, such as a 20 element WIFI Yagi .

Step 3: Printing the Yagi Diagram

Picture of Printing the Yagi Diagram


The most essential point in printing the template is getting the correct scale. In the attached zip file below, are three png picture files.

The antenna is longer than an Letter sized or A4 sized paper. So you have to print the template in two parts (labeled part1 and part2 in the zip file). I have also included the full sized unsplit template if your printer can handle large enough paper.

PRINTING:

Make sure to set your printer's properties to ORIGINAL SIZE (not "best fit to page" ect..).

Set the print orientation to LANDSCAPE.

VERIFYING SCALE:

Use a ruler or caliper to measure if the print is of correct scale. You will notice vertical bars crossing the horizontal line. The vertical bars represent the Yagi "elements" which will be made from paperclips. The horizontal line is the backbone of the antenna which will be build out of popsicle sticks.

You will also notice numbers next to the elements. These numbers are in pairs. The first number is the length of the element in millimeters. The second number, is the distance from the start of the diagram to the element, in millimeters.

Measure the size and position of a couple of elements on each prints. If your measurements match the numbers on the diagrams, then your print is to scale and you may proceed. Accuracy need not to be tight for the antenna to perform well.

Now superimpose both prints, until they match at around element 10 or 11, and tack them together with scotch tape or white glue.


Step 4: Cutting the Paper Clips and Fixing Them

Picture of Cutting the Paper Clips and Fixing Them

You have to trim the paper clips with a nibbler or plier to fit the vertical bars ("elements"). This is fairly straight forward. Lay the paper clip on the template's element and mark the ends with a marker. Snip at the marking.

Make sure that each element fits correctly the length of the bar on the diagram.

Fix the elements in place with crazy glue.

Leave element #2 for later. This is the element that connects to the electronics and is called "the driven element" (as in being driven by electronics).

Step 5: Building the Backbone

Picture of Building the Backbone

The backbone holds the shape of the antenna. I just cut pieces of popsicle sticks and fit them between the gaps of the elements. I used white glue to fix them in place.

Start from element #15 backward. When you arrive to element #2 move on to the next step.

Step 6: Building the Driven Element

Picture of Building the Driven Element


The "driven element" in a Yagi antenna, is usually the second one from the start. It is the element that connects to the USB WIFI or 2.4 GHZ electronics.

It is a broken loop and not a straight wire. A loop of wire resonates at a specific radio frequency depending on its dimensions. The dimensions of the driven element in this antenna is set at 2.4GHz, of course.

It just happens that its about the size of a common big paper clip. You need to clip the paperclip so that it loops around and meet in the center but the end not touching, leaving a gap (see photo).

Fix it in place with crazy glue and build the back bone around it.

When all the elements and sticks are in place, reinforce the antenna with another layer of popsicle sticks. Glue full lengthed popsicle sticks on top of the antenna. The antenna should become mechanically stiff. Then rip the paper template of the antenna.

Step 7: Connect the Antenna to the Wifi Modem

Picture of Connect the Antenna to the Wifi Modem


This is the most difficult part and depends on the electronic hardware you have. please read this step carefully. 

The basic idea is that you need to solder a wire between the WiFi board's RF output and the driven element of the yagi antenna.

But USB WiFi modems come either with an internal antenna or with an external antenna. Those with external antennae, like mine, are easier to connect because you are just replacing the external whip antenna with the Yagi. Those with internal antenna may need to have their on-board strip antenna modified as illustrated in the pictures here. You need to slightly experiment in this case.

I have tried soldering a coax to my board's antenna connectors and the two ends of the yagi's active element loop but it did not work in my case. I have no explanations why that did not work, but other DIYers that have built Yagi antennae connected their antenna in this manner.

In my case, I just connected a single thin strand of copper wire between the active element of the strip antenna and one end of the loop of the driven element.

Please read the annotations of the pictures for more details.


Step 8: Performance

Picture of Performance


The performance was pretty spectacular for this easy to build antenna. I was able to see the WiFi of a hotel that was 2 miles away from my home. The most difficult part was connecting the antenna to the USB modem.

Comments

Saarducci (author)2013-09-21

Okay well I read through the entire post and I saw many things that made a lot of sense, also saw a lot of unnecessary flaming, but I do have a few comments to make. Right off the bat the one individual that asked about having his modem in the basement with a rotating antenna on the roof needs a reality check. Overlooked in the connecting the USB dongle to the antenna was the transmission line length, for these frequencies it should be as short as possible and a multiple of 1/2 wavelength I'd suggest as close to 2.41 inches as one could manage (use a small diameter 50 ohm coax). Take the dongle apart and connect a USB extension cable to it and mount it directly on the antenna assembly. Paper clips vs copper, at this frequency it's not going to make much difference, however the specific model was generated using 14awg copper. Someone said glue it all to cardboard then cover it with more cardboard actually a strong and stable design, original author said build around popsicle sticks(wooden), both are subject to absorbing moisture from the air and either can have a poor dielectric constant, I would suggest some kind of plastic (they make popsicles with plastic sticks). The lengths of the elements, the spacing between them, and keeping them all in the same plane and parallel to each other is the most important consideration. The driven element, #2 in this design: that one I would make from 14awg copper, I'd make a simple dipole rather than a folded dipole, I would take two pieces of wire make 90 degree bends in them cut the bent part to about 1/8 inch and attach my transmission line. Take a piece of heat shrink cut two notches in it about 1/4 inch apart and insert the wires into it and shrink it, maybe reinforce the space in the center (break a tooth from my comb and stick it in the middle before heating the shrink?) cut it down to the correct overall length and insert it last. If you use the folded dipole make sure the folded part is perpendicular to the plane of the rest of the antenna and use 300 ohm twin lead to connect to the dongle, but your SWR will probably be much higher, reducing your effective gain and possibly resulting in early failure of the dongle. Horizontal vs vertical, after you have your antenna connected and have connected to some network you can try rotating it about its horizontal axis to see if you can get a better aspect on the other antenna (more bars). All in all though good job to Biotele, it's cheap, it's easy, and if done right will provide excellent results. I did not build this antenna, but I built 2 antennae very similar before reading this post, My son and I live almost 2 miles apart and either of us can stream 1080p movies from the other's house during a thunderstorm.

Phoghat (author)Saarducci2015-07-20

thanks

Squidyman (author)Saarducci2014-07-26

I think you could make an instructable out of all that :D

ashtra519 (author)2017-09-20

i am going to work on it!! thanks

hamamam (author)2015-01-21

I tried to built it but step 7 is so hard so my usb was damaged , but any where this was amazing topic and I appreciate your effort . any way I get a professional wifi antenna from chines store with very cheap price and high gain , that is it

http://link.cashat.pro/158m5me

elektrofreak445 (author)hamamam2017-09-11

the asus usb n13 wifi card is easy to open and solder these wires onto and such chineese are sometimes fake

ArakR (author)2017-03-10

Can someone please make a video with the instrucions in the comments, because its very difficult to follow.

Can I use a USB Wifi wireless WCDMA router for this? Can you give me a model of something acceptable?

I need to catch the signal on 50 meters sometimes, sometimes longer.

RobertS203 (author)ArakR2017-07-24

50 meters? That is 6 MHz. Wifi he is describing is 2400 MHz. Take a look at a stepper ir. They tune thru that band and are around $6000. It is a huge antenna but very good. It is a loop like the formed paperclip. In case you are confused, the term meters is the actual physical wavelength in meters of the transmitted signal. The lower the frequency the bigger the antenna has to be. It is factored on 1c, which is the speed if light, 299792458 meters per second. Rounded to 300,000,000 you divide this by the frequency in cycles to get the full wave length. Shorten it by using 300 for length of light / speed and 6 for the MHz instead of cycles and you get 50 meters. A balanced antenna such as a dipole is a 1/2 wavelength, so divide that by 2 for the physical length of a 50 meter dipole, so 25 meter length is correct. For 50 meters you are talking about a huge antenna. You can build an active antenna for just a receiver or use an LC network to tune a shorter wire but it will be compromised in ability. Hint: the antenna is a network, compromising of everything from the board connection point, all the way to the tip of the antenna. Using coax, you will also need a balun. I'm an extra class ham radio operator and an electrical engineer. Look online for antenna calculators will be your best bet. Beverage antennas are great, especially for summer time noise from lightning static crashes but they are even bigger. Sorry for the delay on the post but I just saw this.

ArakR (author)RobertS2032017-07-25

By "cat5e" you mean RJ45 cable? I dont know which ones of the wires inside to connect to the antenna? Why do I need a coax if I put an RJ45?

ArakR (author)RobertS2032017-07-25

Ok, I built the antenna according to specification, but I am guessing I couldnt make the elements as accurate, I catch a signal from about 1km, but I cant connect to it. I am not an antenna expert. So if I buy a yagi antenna with coax cable it should work allright?

RobertS203 (author)RobertS2032017-07-24

One more thing. If you are mounting this any distance from the wifi, db loss is extreme on higher frequencies like wifi 2400 MHz. Keep the coax short as possible and use cat5e to get to your laptop. LMR400 is a good all around coax but is is nearly 1/2" diameter. The higher the frequency the larger the center conductor has to be because of "skin affect". You can use a short piece of smaller coax and then adapt it to a larger coax. LMR has superior shielding also. Every 3db loss is half of the signal strength. 6db is 75% loss. 9db is 87.5% loss. Every 3db cuts it in half each time in the math. Antenna gain and loss are added to get the ERP...effective radiated power. 5db loss of coax with 8 db gain on the antenna will give you 3db gain so you can double you wifi output power to get the ERP. Just look into a Ubiquity wifi and their antennas. They are nearly 30dbm...1 watt with some very high gain antennas. That can get you 60 km distance if applied correctly...line of sight.

ArakR (author)2017-07-25

Ok, I will check what can I find for cat5e to connect to my laptop, because until now I was using a router.

I think that my elements are not properly trimmed and they are longer so I get a signal, but I cant connect.

myjunkmailbox2013 (author)2017-01-05

The average person is not going to be able to make this because it leaves out the most important step; so I'll try to explain without going into the math : Matching the impudence of the feed line (the wire that connects to the folded over paper clip). RF signals at this high frequency is VERY sensitive to length. It is critcal to cut the lengths perfectly, also the lengths are for copper wire not steel. So the best material would be solid copper wire that you can buy at the hardware store. I used 18ga and kept the lengths within a millimeter of the size.

1. For the connecting wire you MUST use 50 Ohm coax cable. It comes in 75 or 50 Ohms and its usually printed on the side. If you use a plain old wire this becomes part of the antenna and you lose the "quarter wavelength" that tunes this antenna to 2.4Ghz. Bigger is NOT better with antennas. The best reception comes from keeping the antenna element EXACTLY at this length. Skipping this will give you worse reception and there is no point in making at that point.

2. Solder, dont tape the center conductor of the coax to the center paper clip at the very edge of one end. Don't form a loop, keep the ends electrically separated and keep the paper clip at a 90' angle to the other paper clips, don't lay it flat, that messes up the length between the 1st and 3rd paper clip which are the most critical lengths.

3. Keep the coax as short as possible. Anything over 3" is going to turn the coax into part of the antenna and this can burn out the wifi transmitter. When you solder it to the trace make sure you connect it the beginning point if the antenna if its a "squiggle" shaped antenna on the circuit board. If you solder to the end you have screwed up the length. You will also have to scrape away part of the trace that forms the rest of the antenna, this is permanent so it your not sure be cautious. if there is a connector it will be very tiny and the best way id to cut the cable coming out and connect that. The inside of the cable goes to the inside of your coax and the out must also connect. Some coax cables have aluminum and solder wont stick to it; while still useable it may not be the best choice if you are not experienced with building electronics.

4. Better way to make the driven element: The outside conductor of the coax must be connected to the ground of the wifi device. This will be outer ring of the connector in your device, this will connect to the shield of your coax. Take the folded over paper clip like in the tutorial but instead of making a loop, make it the length in the print out as a straight piece. Cut the piece in half. This now becomes a dipole antenna, and will work better because it used the ground in your wifi device. Solder the center conductor of the coax to one half and the shield to the other half and glue them onto the popsicle stick with a very small gap between like in my picture.

5. Finding the ground: this is probably the hardest part. For this to work you need to hook the outside of the coax to the ground. If there is a connector in your wifi device it the outside conductor of the connector. If you just have a squiggle you are going to have to find the ground plane on the circuit board. This is usually a very thick trace that "floods" the circuit board where one side of most of the parts connects to. There is really no easy way to spot this without some knowledge of electronics. If you don't do this step it may still work but wont work well if it does defeating the purpose of this DIY.

If you want to learn more look up wavelength and 1/4 wave length. Its a complicated subject with lots of math. Unfortunately this project just wont work if you skip steps or mess anything up. Seems simple but really everything has to be done right for it to work. Hope this helps.

danielem39 (author)2016-12-23

Thank you bro... I try to make it, but I have a question: I have a USB dongle WNA1100, can I use it?

I have disassembled it and I found a connector for antenna,can it works?

White wire is take from a old notebook acer with WiFi.

If connect yagi antenna on this connector isn't possible,how can I use this dongle for this scope?

Many thanks

Youssefa55 (author)2016-12-19

thanks

gossa made it! (author)2016-11-30

Works quite well. Thanks!

mike10046 made it! (author)2016-09-21

It worked out very nicely. -40dBm internal WiFi card, -23dBm USB WiFi dongle +9dB antenna and -7dBm homemade yagi attached to USB WiFi dongle pointing a router

-7dMm homemade yagi attached to USB WiFi dongle pointing a router

Rahulsinh jadeja (author)2016-06-23

Can anyone tell me how to connect this to laptop

pranshul12345 (author)2016-06-06

I am using TP link wn722n
And want to make yagi antenna
I had made antenna but I did not getting an idea to connect it to my TP link wn722n
Please Help

BryanJ28 (author)2016-02-24

Which cable should i use to couple the antenne

lawrence.rhodes.3 (author)2015-07-19

My problem is going through a wall and then a floor. I'm lucky to get 10mps from a 30mps connection. I'm using a D-Link DWA-130. It has an extension with a 45° angle base. It seems the best position is the face of the unit aimed toward the router in the basement. A bit of aiming and draping of wire is needed. Is it possible to build an aluminium foil bowl to focus or bounce the waves into my unit. Just a thought.

try cutting a can in half and place it behind it. It should give you some increase, but don't count on to much, you probably have a bit of package drop due to interferance that decrese your speed

NaderA1 (author)2015-08-26

The way the paperclips are connected to the device is not clear. It seems they are just glued on a pieace of wood with no wire and no connections. I am missing something?

Anoop M N (author)NaderA12015-11-27

yes they shouldn't be connected. they are separate elements

ArcxangelT (author)2015-11-11

ok i gonna try it and if works i come to comment

spystealth1 made it! (author)2015-10-26

Great instructable! It's amazing what one can do with such basic materials! I've wanted to build a Yagi for a while, but the simplicity of your design finally pushed me to do it. Unfortunately, it doesn't seem to be working. :( I'm using the standard network scanner on Windows 10, but the antenna doesn't seem to be seeing any networks besides the usual. The measurements are correct and I'm using coat hanger wire (so they're presumably iron not copper). I will say there is some slight bowing of the rod, but I'm not sure whether it would be enough to cause signal loss. As you can see, I've mounted an Alfa AWUS036h on the back. Could this be interfering with the signal? Any help would be appreciated. Thanks again for an awesome instructable!

DragonDon made it! (author)2015-10-22

Tried my hand at building one. Turned out not bad, was neat to see that while I could see a lot more signals, the average signal strength was about half strength. Neat project though.

Album with pics of finished antenna, then screenshots of signal strengths. https://goo.gl/photos/57gMW6uPbK8oJ3nG9

https://goo.gl/photos/57gMW6uPbK8oJ3nG9

goldenskyhook (author)2015-08-25

Two questions. First, how can I fix it if the scale is not correct? I think they are the same relative distance apart, but it doesn't match up to the mm listed on the printout.

Second, could I use this on the router as well, or is it only to boost the receiver located at the computer or device? Thanks!

stuffdone (author)2015-08-04

Think I will make one..but use a piece of 1/2 CPVC pipe for the spine rather than wood sticks. Think it will look nicer and be more weather resistant as well.

mauritius0001 (author)2015-07-20

Hi - I think the greeen pad is the USB Wifi modem ?

Thanks to have details and possible suppliers

Regards

Baboo

jimrittenour (author)2015-07-20

Can someone make a schematic? That would help us who need to visualize it.

Wazzupdoc (author)2011-10-04

I think the reason your original antenna hookup didn't work was the geometry of the driven element. For a clear explanation see http://makeprojects.com/Project/Homemade-Yagi-Antenna/623/1
She builds a larger Yagi, but the principles are the same. Neat ibble, though.

Biotele (author)Wazzupdoc2011-10-04

it is working with one wire driving the loop.

RobertG8 (author)Biotele2015-07-20

It would work better if you connected the ground plane of the antenna to the ground of the transceiver though the shield in the coax. It probably didn't work for you because you hooked it up to the wrong place on the loop.

Arduino4Me (author)2015-07-19

Thank you so much for sharing this!

:)

XXXX3 (author)2015-07-19

"The diameter of the wire in the elements has a direct influence on the capacitance of the element" This translates in practice to wider bandwidth (the radio definition, not computer) especially at lower frequency , which is why TV antennas are made of tubing and not wire.

I built that BYCSHSPWE thingy but never could get any steam!!

racer283 (author)2015-07-19

Can this be used in a wifi reciever?

racer283 (author)racer2832015-07-19

Okay... yes it can.

nathanaloysiusbash (author)2015-07-19

If I could connect a second router as a wireless access point could I replace the antenna with this or is it just for recieving? This is all quite over my head but im pretty sure i could do the build something out of paper clips part. Ill have to read this all again more thoroughly later.

AnthonyS9 (author)2015-02-15

Hi there, can somebody please help us, ... we have an issue at our rural property (not too rural but) where our 3G smart phones work okay outside but inside a timber framed house with a metal roof they don't work at all, we were told to install a Yagi 850 MHz Antenna outside on the roof and the shortest cable possible into the house with a phone cradle, which then makes the phone not mobile and stuck in one place, it is legal to buy and overseas mobile repeater , so can somebody please tell me if this would work, ...placing a Yagi Antenna outside, with a smaller car antenna attached to the other end inside - would the small car antenna acts as a repeater inside ?? we cant afford the ridiculous price tag the 2 telcos are offering for their smart repeaters (over $1000) so was wondering if this is a ridiculous idea or not??.

apparently if we are receiving a good signal outside the house (4G and 3 G) then we would have no problems inside the house.

Regards Anthony

yrralguthrie (author)AnthonyS92015-07-19

Your idea won't work. You will have to buy a repeater. But be aware that getting a better signal for a cell phone can be a difficult. The best thing for you to do, regardless of what country you live in would be to google Wilson Antennas and then call then and explain the situation.

The repeaters have several antenna options. You have to have two antennas . If there is only one cell tower in your area then you can use an omnidirectional antenna high and low. If there are two or more towers then you will need to install and orient a directional antenna to null all but one tower. Where you place these antennas will have a huge effect on your results.

A repeater system will not get you a strong signal. It may get you a signal that will work. Cell phones are incredible sensitive. If you can operate your cell phone reliably outside you should be able to get it inside with the repeater, but not necessarily in the whole house. The repeater will not get you a large operating area. Some say they will, but they are basing this on ideal situations witch do not exist outside a testing setup

If you buy a Wilson cell phone repeater and it doesn't work the chances are you have installed the wrong antennas or the antennas are in the wrong position. You are going to wind up paying $400-$500 US.

Oh, in the US the cell phone people managed to get law passed that says you have to tell them if you use a home repeater. They have no way to tell if you are unless you do tell them.

Don't expect too much. If you just need a good strong signal in one room then they usually work fine. If you want a strong signal everywhere in your house then they don't work so good. The key is the outside antenna. That weak signal that your cell phone won't work on, is also too weak to amplify. There is also the chance that the signal is so low that no antenna can pick it up. Most cell phones have a signal strength meter, open it and walk around your property. If you can't find at least a signal level below 110 db (lower is better) then the repeater won't work. You don't have to understand what a db is just that lower is better. If the signal fluctuates when standing still the repeater won't do you any good either. In other words if you can't find a place where your cell phone will work on it's own, then a repeater won't work either.

A repeater works by you being able to put it's outside antenna in a place where there is a signal (that will actually work with the bare cell phone) then amplifying that signal and redistributing it using another antenna. A weak but usable signal outside will get you a somewhat stronger signal inside. A strong signal outside will get you a good strong signal inside with wider coverage inside.

I think for the internal antenna to act as a repeater you'd need a device to power it and transmit that signal. Maybe the thing to do is buy the Wilson powered device for your carrier's 3g frequency. Plug it in to the outdoor yagi and indoor antenna and that should do it, as far as I know. But I'm pretty sure that situation you're describing would need some power input to make the repeater work.

MikeJ20 (author)2015-07-19

looks like an old school TV antenna to me

XXXX3 (author)MikeJ202015-07-19

That is a Yagi.

thegreekgeek (author)2015-03-03

So I have a question for all you more knowledgable types. I purchased a external wifi adapter to go with my homemade yagi, and unfortunately, i purchased the wrong type of connector for my antenna (purchased a coax cable with male SMA connector instead of a RP-SMA connector). My question is, is it necessary for me to connect the shield and the inner conductor to each end of the driven element, or do i just need to connect the inner conductor?

Aaaand I think i figured it out. Didn't read the annotations of the third picture.

diy_bloke (author)thegreekgeek2015-07-19

i read the annotations and i still didnt figure it out :-)

diy_bloke (author)2015-07-19

nice, but it is unclear to me wher you solder yr antenna. 'the active element of the strip antenna' and the 'driven element'
Ok the driven element is the round paperclip, but what is the 'active element'
and what do i solder on what? does the core go to the active element and the shielding to the driven element? or the other way around?

mdblocher (author)2015-07-19

Will Legal size paper be long enough?

yrralguthrie (author)2015-07-19

For those with limited experience making antennas, and to keep from having to open up the WiFi router and soldering wires, it would be far easier to just get a USB gain antenna and connect it to your computer. You would have to install a software driver on the computer, but this might be easier for a lot of folks.

In one case the gain antenna is attached to the WiFi router and internal antenna on the computer, and in the other the gain antenna is used by the computer and the regular antenna is used by the router. There is no hardware modification to the computer, only software. And of the two antennas, the one in the computer is usually the weakest link. I have a usb antenna and when I use WiFi in my shop with the laptop the signal is very weak and intermittent. With the usb antenna connected the signal is 3-4 bars.

If you are trying to increase the range of several surveillance cams then the yagi on the WiFi router won't work anyway, since it is so directional it can only be pointed at one device. And to use it with your laptop you will have to use the laptop in only one direction. The direction the antenna is pointed towards. The usb antenna on the laptop on the other hand will allow you to change positions.

If you're trying to connect several surveillance devices through a router to a computer, it might be better to get a WiFi repeater(s). Then place them between the surveillance devices and the Wifi router. And then if the signal is still weak to a laptop location use either another repeater or a usb antenna. The usb antenna is usually cheaper.

If my humble opinion the best use of a high gain Yagi antenna is to steal a signal. Much easier to just drive a little closer. LOL

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