Is this Really an 18dbI WiFi Antenna?

In this video we take a look at an 18dbI 2.4GHz wifi antenna from eBay. I also discuss why people are sometimes disappointed with the performance of high gain omnidirectional antennas.
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[@scienteer3562]

Just for the record. Neither of those antennas(black or white) are anywhere near 18dBi. Possibly 9dBi for the white one. An 18dBi omni will need at least 6 or 7 elements in it, probably more. Each element can add at most 3dB.

[@haggar11]

Thanks for review Andy, indeed loads of them around in Ebay.

[@wivaquif]

Just about to buy a couple of these for my wireless cctv set up. Glad I watched this video. Many thanks

[@RaffaelloKWOS]

Hi Andrew I bought one of those antennas a time ago but never used it. As soon as I return to the office after the holidays I will test it with a VNA and let you know on which frequencies it is tuned. Surely, seeing the folded dipole, it looks at least on two frequencies. It looks like an unbalcanced dual dipole. The ground is 1/4 in size. What is sure it is not and antenna with 18dBi of gain.

[@anthonyaguir9340]

What those silver things do? I can't find any info on the internet. Thanks a lot.

[@hadyant0]

my router Asus RT-N18U , i replace original antenna with 2x TP-LINK TL-ANT2409CL and 1 Alfa network APA-M25, i got coverage 30 meter in house even 50% in the bathroom, the best setup i get without a repeater.

[@freefilms10000]

Fascinating as ever, please show us how to make the white one, thickness of wire, length of coils etc.

[@alexanderwolfe8782]

I bought that very antenna from aliexpress, and received it last week. It is most definitely not 18dbi and in fact showed very little improvement over the 3dbi stock antenna from my wifi adapter. If you look at the reviews of other "18" dbi, "12" dbi, etc antennas there's a pretty common pattern of them being 5dbi or worse. Maybe up to 8dbi if directional. Ah well, perhaps I can disassemble it and recycle the connector.

[@johnwest7993]

Good question. What's a 'dBl'? Regarding antennas I'm only familiar with dBd's and dBi's.

[@samandarabdulla7503]

Thank you very much .

[@jovabre]

Thanks you for review you saved my money and time. I will buy a withe one. I'm averred of signal propagation.

[@DustInTheWindAZ]

The "dBi" rating is a theoretical measurement based on modelling predictions that cannot exist in real-world conditions. As they say in the antenna world, "Everything affects everything"! Metal structures both shield and reflect radio signals. Placement of your antenna (regardless of type/frequency) is critical!

[@andrewmcneil]

Agreed, but most people see it as a performance factor when choosing an antenna for cellular or wifi and sellers take advantage of this.

[@elmushi]

the one you are showing is the fake one, however after watching your video, i disassembled the same antenna that i have , and it have bigger board and different than yours. so seems like there are fake copies of the better ones maybe. thankyou

[@gregorygorham9793]

Hello Andrew. I was curious if you have compared any of the different models of ALFA cards. The one you feature is one of thier cheapest and i was interested to know if that was because the modified antennas you create make the model of card irrelevant or if there truly is a benifit or noticable differenc to some of the other ALFA card models. Especially since the prices seem slightly misleading or fail to correlate with listed features or performance capabilities.

[@MrZerohour1967]

Agreed, there is no way that antennas was going to be 18dBi no matter what was inside it. But testing antennas inside like that really doesn't prove anything. So many reflection, and testing the antenna ability to pick up random sources is hardly a way to verify gain. I'd rather see you measure the return loss in fee space, then check the gain on a remote source in fee space, then you might start getting results that have some validity.

[@Rtkc3381]

Exactly. I am desinging my 315mhz dipole antenna. But near my home, some seller were introduced some the china antenna type have 15, 18, 30, 35 dbi. This is awful. I don't understand how they can achieve such a high gain when not in use yagi-uda or reflective dipole array antenna

[@ITech2005]

A China antenna? Lol They lie about their products. Easy answer.

[@PedroDavidMoran]

Hi Andrew! That 18dBi antenna looks a lot like a HD tv antenna......Hum...That just gave me a "reverse" idea just to see what happens... : D Cheers. See you around.///////// Ooops. sorry: Great Video as always!!!

[@andrewmcneil]

Thanks Pedro and yes it could well be

[@rocketman221projects]

It's clearly an 18dBdl antenna (dB dummy load) not 18dBi. It would take a good sized yagi to get 18dBi.

[@MrDinakdakan]

thank you

[@iyeetsecurity922]

I recently purchased a 2 pack of "12dbi" antennas that look just like that fin one for $4.99. How can you test it to know for certain the legit dbi on an antenna?

[@ibrahimbakhtiyar3201]

Which antenna should we buy

[@titopalmira399]

n the 18 decibel white antenna that you opened as the element that unites the lead-colored coils is called could you instruct me what is its function and excuse my english i'm learning it

[@HyukjoonKwak]

thanks for test.

[@carlosdavila4164]

buen trabajo saludos desde colombia

[@juliasanchez9055]

I don't fully understand why you stated you were receiving underwhelming data because the card doesn't have much output. If you are receiving why would you need to have a 1 watt amplifier? Neither the black nor white antennas are 18dbi obviously, for an omnidirectional antenna to achieve that it would have to be fairly large. If you are just receiving signal, the output doesn't matter because you aren't really outputting anything in those tests. Looks like you tested a cheap 5ish dbi antenna against a cheap 6ish and a cheap 8dbi antenna, or something similar; wouldn't be surprised if they are all 6dbi The vast majority of people selling these antennas without an actual company name and such behind it just lie because they know most people buy the highest number. It's like buying a 900lb smart car and being surprised when it doesn't actually go 0-60 in .6 seconds Love your channel, best wishes

[@leonardoalmeida990]

Do u know where can I buy good ones?

[@midnitelitecompany]

Andrew I have an elementary level question that I hope you will oblige in answering. I am attemping to make my own bi quad antenna, do I solder the top to the driven element, and the bottom of the copper to the ground? Is that correct? Can anyone clarify this rookie level question for me? Thanks!

[@jorenvangoethem343]

how could you increase the 300mW and how would much that help

[@NoilsonCaio]

Well done

[@big5astra]

Hi Andrew, could you please comment on how these 3 antennas may be useful to use - or not - for a 2.4ghz radio on radio control model planes. Thanks

[@Wheelabarraback]

It probably would give you greater range.

[@tedfix3940]

show me how to connect it with my phone

[@ThaVoodoo1]

Would be nice if you had an antenna vector analyzer (cheap Ebay ones) too test these with.

[@andrewmcneil]

I have a scalar network analyzer hp 8757d not worth going through the calibration setup for this antenna as it clearly is not 2.4

[@Manishkumar-dj6kl]

@@andrewmcneil sir can we use power y cable with alfa wifi card?

[@bananenrepublikdeutschland9043]

no pain no gain!

[@monkunderground4244]

На 9.22 я чуть со стула не упал от смеха. :) В моём роутере "Mikrotik Chateau" встроенные антенны и то гораздо больше чем этот ужас на зелёной плате.

[@mae5637]

for short answers, its a fake and weaker than 5dbi, its a 5dbi but its 1.8g not 2.4g =, ITS FAKE! DONT WASTE UR MONEY!

[@catalinalb1722]

Would be nice to know for what frequency it is. Anyway thank you for the video.

[@midnitelitecompany]

I think that he assumes we (those of us into RC) would know it’s 2.4

[@dhonzlimlingan0118]

Can i ask private message?

[@VaibhavKurde]

Hi, You just said, these are just antennas and not an amplifier. You will need amplifier to utilize higher gain antennas. Do you have any circuit diagrams for good wifi amplifier? Plz help.

[@kmom777]

nice video 100 points

[@DavidLopez-bz4rj]

No

[@andrewmcneil]

You got that right David :-D

[@DavidLopez-bz4rj]

@@andrewmcneil I always thought about making a rhombic antenna for 2.4GHz, maybe you could experiment with them. I like making copper circular waveguides with chicken coop mesh as a horn, 18dbi is easy to get, but less gain horns are great for wide coverage. By the way, I dont use connector on the antenna side, but tin soldered brass tubes that fit snugly against each other to strap the braid.

[@andrewmcneil]

Yes I was looking at that antenna a couple of years ago. I jotted down a few ideas but never built a prototype.

[@DavidLopez-bz4rj]

@@andrewmcneil Its a beautiful antenna, and here at 2.4GHz, it can be made many wavelengths long, like 100 lambda or so each side of the antenna. It can be rotated to vertical polarization, unlike HF. Impedance matching is the biggest issue I can see, it needs a balun to balance the antenna and match 300-600 ohm, depending on the value of the resistor, although I made some modelings of non terminated rhombics near 50 ohms. There is an old 1296mhz design online of the Laport Double Rhombic, just needs resizing to half.

[@Janom66]

🤔👍👍👍👍👍

[@ninjapcmaster7005]

make 18dbi pcb antenna !!!!!!!!!!!

[@8sport]

Can you make 18dbi antenna wifi 2.4ghz.

[@PedroDavidMoran]

Sure He can. Blindfolded. and more!

[@VaibhavKurde]

Made already or not?? Source please..

[@kltang_gala6709]

It's really really fake antenna

[@fahadwish4795]

gd

[@8sport]

😆😆😆😂😂😂😂😂