Double Yagi Wifi Rig

[@BlueScreenOfDead]

Wow, the design looks realy good !

[@mihai1339]

Please do speed tests for the wifi antennas you are building ( and maybe compare their speed with the speed of a 5dbi rubber duck antenna )

[@freefilms10000]

well said. Precisely

[@tmpserg]

so clean look and accurate crafting but what kind of engineering madness this driven element is? can u check this antenna on SWR-meter?

[@tasmedic]

I wonder if we'll get an explanation of that driven element. "Some kind of copper tubing"!! It does not look right to me either. Get it wrong and the output stage is likely to burn out or overheat and die prematurely.

[@tmpserg]

well...modern adapters do not have much output power to burn something :) even such weird antennas with SWR=5....10 will not damage your adapter but yes, it is Very strange thing if you think about it, tiny cuts do not change SWR much, inserting coax into folded dipole really making balun, BUT it still 280 ohms folded dipole Andrew, please check it on SWR-meter

[@stridermt2k]

I really enjoy learning more about working with hardware at these frequencies. I used to thing that 2.4ghz and thereabouts was out of my reach...until I started doing it, then of course one picks up techniques! Techniques easily used in other similar RF applications as well. Thank you for your videos and sharing your projects and evaluations! 73 de N2NLQ

[@razblack]

if you fill it with sand or salt, flatten the ends and seal with solder then bend, it will help prevent the unwanted crimps. Once you have it to shape, you can cut the ends off.

[@terrygee210]

Andrew, thanks for another great video. I have two ebay wifi adapters which look identical to yours there, but branded 'Etekcity'. On both of them only one of the two sma connectors is active, although the the pcb circuitry for both is there and looks ok at first glance. Are both connectors active on your adapter?

[@marcino7769]

I really admire your ideas. Keep it up!

[@Jonny10001]

Hi Andrew, the impedance of the folded dipole on you Yagi would be around 175 ohms. A matching 3/4 wave stub of 95 ohm coaxial cable should be used to feed inside the folded dipole as this will create a 1.1 transformation. From there on standard 50 ohm coax can be used as the feeder line. The 95 ohm coax is available on ebay as RG180. Try it out and see the improvement in the SWR.

[@tasmedic]

Do you really think he checked the SWR? He didn't even take the adapter apart to check that it had outputs on both antenna connectors before he started. He also seemed to get the concept of director and reflector elements mixed up.....

[@freefilms10000]

nifty copy of two turbotennas. May I suggest you substitute that thin coax with thin 75 ohm tv coax? the twin sky coax is ideal. I used to use decent 50 ohm coax, till I discovered 75 ohm was vastly better.

[@freefilms10000]

Please would you do a test with only ONE aerial connected and compare results? May I also suggest you use 75 ohm tv coax, same length, instead of that thin stuff?

[@freefilms10000]

you will find if you make several of those dipoles, some larger, some smaller, trying each in turn, that adding more directors will either increase or decrease the gain.

[@Belfor09]

Real question here mr Andrew. Why do you use Alfa cards? Do these put out maximum rated power under windows 7/10? You are not constrained to 20dBm (or whatever EIRP is in your country)?

[@dukenuke2690]

Yeah i would also want to know that, how much of a difference do different usb adapters make?!

[@oscar3611]

I have the same adapter, and I think this setup won't work that good. From what I found out about this card is that the first antenna is for receiving, second for transmitting.

[@gordslater]

Careful cutting the outide of the driven element - you are reducing the effective lenth of it because the current is now only passing on the inside of the curve, shortening the length of it. It will then act more like shorter-but-fatter element, because the extra metal is still attached but current doesn't flow on the oustide of the bend due to the cuts, but the element is still thick. IYSWIM As a result Q wil be reduced as well as changing ther resonance upwards in freq. edit: see side view of loop at 16:41 - measure the distance around the intact part of the tubing of the loop and then measure the outside of it. Difference in this length maps to change is frequency. Due to the thickness of the element being a significant proportion of a wavelength at WIFi freqs, this can have quite an effect. Contrast that with the same arrangement at say 10Mhz and there's little or no effect. Just change your overall length to compensate - should be easy enough because you have an anal spectralyzer to help you :) (but note the Q reduction can give the impression that there;s no need, due to flattening of the response curve. Low Q is your enemy because it leads to lost eficiency (gain) though in some cases it can be useful to provide a wider response , but always at the expense of lost gain) High Q is hard to achieve at WiFi freqs and you need to try and preserve it any way you can. Above 2 or 3Ghz the response curves of antenne are usually too wide anyays, rather than too narrow.

[@tasmedic]

He didn't even take the adapter apart to see if both output connectors were active. No comparisons with anything either. It's a fairly random home brew project with a suck it and see approach.

[@qcsupport2594]

Great stuff. This video reminds me of a related question: for a wifi router with multiple (directional) antennas, does it automatically select the one with the strongest signal for sending and receiving? What about when it has MU-MIMO capabilities?

[@JamesThompson-xl4yu]

Looked to me the driven elements are directly shorted by the square tubing ? Did you insulate the copper from the aluminum tube?

[@andrewmcneil]

No that's how this design works

[@JamesThompson-xl4yu]

@@andrewmcneil Being a ham radio operator and this wifi is also a transmitter, the coax should not directly short on the center to shield like this or it will burn out the rf amp in the adapter, maybe not immediately but it will degrade over time.

[@tasmedic]

Directors are in front of the driven element, in direction of gain, reflectors behind. To avoid any confusion....

[@OtusAsio]

Did you test those yagi antannas to see if they are at 2.4Ghz ? Thank you... (I am not into antennas but like to see all opportunitys to learn something, an maybe use it in the future)

[@lorinrandall3508]

Hi Andrew I have another question foryou watching on KZbin I see the Indians all using any type of coax they have from the looks of it most of it seems to be 75 ohm coax I know that RF calls for 50 ohm coaxare they really getting the range that they say that they are getting using the 75 ohm coax can you explain that to me please.

[@danielr.schafer9504]

Looks great!

[@tmpserg]

Andrew, it is gonna work MUCH more stable if you place mounting box of folded dipole on the same side of boom with directors And Please check it on SWR-meter

[@Yoganchi]

What type of anthena could possibly connect to lower freq, such as 6-12 Hz? Thanks for your work!

[@DAVIDGREGORYKERR]

You using Alusol solder.

[@jpsimas2]

when you put those close together like that don't they couple with each other and get unmatched?

[@testchannel1834]

can you do a new one for 2023 with the new alfa 036uAXM. 2.4/5ghz/6ghz Please

[@xXxTonyLongoxXx]

Please could you do a video making a six quad antenna for 2.4 Ghz? I have seen a video made by someone making one of these antennas but I think it's not well made... Have you tried building one of them? And if yes, is there an improvement compared to the double biquad?

[@huarwe1196]

Excellent content very interesting.

[@shahidiqbal9580]

please sir make a 4g atena for 1800 mhz i badly needed it. Tried a few through online calculators but neither worked because i think i am not doing the balon and driven elemnt right. Thats partly because the sites or calculators that provide element measurment dont give a practical guide to built a driven element. it will be a huge favour sir please

[@armstrongskyview2810]

Hi Andrew, could you make me canteens bi-quod with the duel module please, happy to pre-pay :)

[@mistersearchmistersearch7977]

Hi Andrew what about six-quad antenna. it is valuable?

[@lorinrandall3508]

Andrew I have a question for you Sir, I am wondering how you get the passwords for WiFi networks that you scan for. Do you use a password crack or what ease help me with this, I missed you for awhile cause you were off but I'm glad you are on keep making these informative videos thanks man...

[@medmusic7977]

Lorin Randall use waircut 2.0 and jumpstart

[@freefilms10000]

he does not need password. He is not trying to use them. He is just looking to see how many he can 'see,' but this is no way to test how good his aerials are.

[@708raju]

Is it possible to design for 5.8 ? ( boost for FPV)

[@80Loke]

This is nice cant buy stuff like this

[@freefilms10000]

Ah, Andrew, you have copied the turbotenna dipole at last. It really is better. But you are still testing your aerials by the number of access points you see. That really is not the way to do it, specially with directional aerials. You need to hook up to a router whose code you know and do a speed test of your various aerials for a proper result.

[@tasmedic]

He's got plenty of subscribers. So I doubt he's bothered about being scientific about things. He's a hobbyist playing with random home brew stuff which might well blow up the output stages of his adapters, but at $5 a time for chinese crappy adapters, who cares?