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Building a 2.4 GHz WiFi helical antenna
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- Опубликовано: 1 авг 2024
- Taking way too long to talk about helical antennas and then somehow trying to build one on camera.
This was supposed to be a part of the satellite reception series of videos, but I ended up not considering it one due to the topic being so broad and applicable in everyday scenarios, such as the WiFi antenna build you will see in this video.
Links:
My website and other social media - sgcderek.github.io/
Helical antenna calculator - sgcderek.github.io/tools/heli...
3D printed scaffold - github.com/sgcderek/dsgc-heli...
Timestamps:
00:00 - Introduction
01:48 - Antenna polarization
04:24 - Helix examples
07:03 - Needed materials
10:14 - Making the reflector
15:58 - Winding the helix
19:57 - Attaching the connector
20:54 - Matching strip
22:59 - Finished antenna
25:00 - Performance testing
27:41 - Conclusion
Music:
Cosmic Love - Bruno E.
Hanging Out - Bruno E.
Sunny Morning - Bruno E.
(can you tell that I didn't bother browsing the audio library that much?)
This is something Im going to try this weekend. Have a garage about 70meters away from house.
Edit: Holy smokes, antenna works as a charm, tested with my phone, and about 50 meters away its still full signal. speedtest also shows same result as if I was standing near the router.
I'm floored by the effort + attention to detail you've put into this. You tackle the most difficult types of DIY antennas with ease. You explain it well and don't get lost in the annoying math.
We built high gain antennas 20+ years ago trying to network our houses together, pringles cans, satelite dishes, flower pots. our ultimate problem was the ficus trees in our area acted as giant radio sponges. we were able to get up to 3/4 mile range in a straight shot.
Yeah shooting microwaves through trees is a losing battle. I'm hoping I can get my hands on some of the 900 MHz routers, that would be quite interesting to see how they compare to 2.4 or 5 GHz, it should be able to reach further and better penetrate obstacles, at lower data speeds
We, too, have the vegetation problem. But a part of me in interesting is seeing what it would take get "borrow" the WIFI from a McD's about a mile away.
Pringle cans.. the memories!
Great video. The humor peppered in cracked me up. You've had the best videos on antennas I've seen so far. I'd love a video showing a DIY double helix for wifi.
Thank you for not cutting out your mistakes when editing the video. This is what it's REALLY like making something of your own! It's good that you know which parameters matter and which don't.
I was glad that you expanded the hole for the center conductor of the type-N connector. I was telling the screen that the hole should be the same diameter as the dielectric in the connector.
It would be interesting to see what the VSWR curve looked like. Do you have a nanoVNA?
Yeah I do have a NanoVNA V2 which can measure these, but I didn't really want to add that information into the video to not make it even longer (and the point was to show that you dont need any special tools like that)
I do however plan on making a loose continuation of this topic where I will most likely do the full measurements as well as long range testing
@@dereksgc Cool. I would really like to see what bandwidth you ended up with.
Love your videos !! Way back, when I started the FCARC ham radio club. A fellow ham and I, set-up a temporary repeater on 444.250mhz. We didn't have an outdoor cabinet to mount the gear in. But we did have an old refrigerator ! So we used it to house the radio, controller, power supply and duplexer. We dubbed it the "Fridge -a- peter" !! It worked out very well and got some laughs too !
Keep up the great work !
I like the use of the old fridge. And the 3D print form for holding the helix.
Another excellent project, almost complete (don't forget the weatherproofing).
👍
Sometimes wrong is better - together we all learn. Perfection doesn’t teach anything, it just looks prettier. Thank you for being honest and real. - So we all learn. Too few channels delve into the realities, they just goo for pretty. Thank you. Subscribed 😊
I am impressed you used a spider as a drilling template for a hole
Great video. Very informative, would love a video on your ground station, and how/if you automate the collection of sat images.
Nice practical video as always, looking forward to more content like this...
Fantastic work, thanks for sharing and explaining all the antenna basics ahead of the built 👍
Greetings to the Czech Rep from Munich, Germany
Dude! I completely love your video style. I don't know anything about HF and antenna voodoo, but I just could not stop watching your video. Hope you get the money to resurrect your refrigerator soon. Thanks for teaching me a little. I wish I understood more about left vs right circular polarization, that hurts my brain a little.
I'm going to try to find a reason to use this in a video. I really love how you presented this. Very useful!
Keep doing videos please, this a gold mine.
Thank you very much for an awesome video with great attention to detail and recording of the results. Your proof of concept is valid. Here in the United States we have many bicycle races, running marathons, and other things where we have rather elaborate communication centers that are set up with data that must travel some distances. Using 100 ft Towers with 1 and 5/8 in heliacs to feed the antennas really gives it the range. I would really be interested in seeing how the helical would perform. I look forward to more from you in the future when you are able to establish stable tripods that can get you above the curve of the Earth.
Excellent video and I love the green fridge idea 🙂
Hey, thanks for your time and effort making this video!
You do a really nice job on your videos! Really enjoyed it.
I was watching one of your other videos and thinking "why has he got a fridge outside?" and thinking you must be crazy or something... now it makes perfect sense!
The 995MHz antenna showed at the begining looks rather like a marine (or currently a submarine) communication equipment not the satellite 😀 You've made my day, really.
You're the first person I've subscribed to and pressed the bell icon for. Thanks so much for your videos! Keep it up!
Great video and explanation 👍 Thank you and keep up the good work 😊
Yeh , great vid well done , easy to follow & simple test . keep up the great work.
I have been thinking about building 4 Helical antennas for, 1296MHz EME. 2 left hand and 2 right-hand polarization with one feed point for a 4.5 meter dish stacked very close together. Those printed coil supports look awesome.
Very nice video I just saw a reason for buying the arcdroid cnc cutter. Also you could a fibreglass radome to cover up the antenna so the frequency cannot be disclosed to the authorities. :-)
Biquad behaves better when there is no direct visibility to the helix. At the helix antenna, in addition to the drop in reception level from linear to circular by -3dB, the reflected signal has reversed polarization and is not received by the helix antenna. It is ideal to use helix antennas in both parts, installed in a place with direct, unobstructed visibility. You can also use a biquad or helix as the primary antenna for a parabolic antenna, which seems to be sitting next to the rack, unused.
Nice work, great instructional video! Some weatherproofing maybe but performance is quite nice.
Great job! Axial mode helicals are my favorite. Subbed
Then get ready to see it again very soon
neat. I built and use these starting in 2013 for my drone photo/video business(at the time). Before then, Soda cans for home wifi (like idk 2007?) Now, am an active amateur radio enthusiast and building all sorts of fun antennas. I don't think I heard it, but your method to attach the center conductor is perfect, but really ought to be measured and kept at a distance that maintains a 50ohm insulation gap, which the hole in the reflector perfectly accommodates. Where it seems it might be too close is that 3d print might be dipping down before spiraling up. But that's just nit picking, and your results clearly are good. Great video!
the fridge server is genius actually!!
Thanks for keep making videos
Thanks for this video. I definitely want to try this with my Internet connection which is cellular based. One recommendation on testing. You should give iperf a try. You could setup the server on a workstation in your house and then run the client side on the laptop in the fridge. That would tell you the true bandwidth between your house and the fridge for the two different antennas. Who knows, maybe the helical antenna is ever better than 4 times.
Drill hole pattern reminds me of the Orion constellation. Could make a stencil for getting the hole positions.
Thanks for you video,super keen to print and build one of these to be able to tap into my household wifi from my workshop which is about 40 m away. I'm not much of a tech head and was wondering what i require after the antenna to have wifi to multiple devices in the workshop.
Great video. Thanks for sharing.
Fascinating!!! Thanks. I’m following
Thank you) Very useful tutorial
great work.
Great project.
you should add some weather stauion stuff just for fun and you you have the space. the fridge is sweet. thank for uploading.
Hi,
Amazing results and great effort in your design. Excellent work. You make the black art of RF antenna design look so easy.
Can you also shed some light on how to calculate the Gain of the antenna ?
You can go to my website helical calculator, which gives you a gain estimation sgcderek.github.io/tools/helix-calc.html
The formula taken from the literature that is quoted there
You might get a step drill for working on the sheet metal...they leave a bit of a chamfered edge, and don't "grab" when they go through, and you just drill to the hole size you need... Safer, and 'cleaner' !
Wow, the print quality on those 3D prints are amazing! What printer are you using?
Niceeee ideaaa. Using old frigde as panel and its watertight, excellent 😂😂
I wonder if you use a wifi 6 AP and wifi 6 device would you get better bandwidth on the same 2.4ghz band?
what is the diameter and of the Helix and what's the space between them. you said this antenna is alittle forgiving on these details how much offset does it take to make it not function just inquiring. thanks
Very pleased to see directional instructions for a russian military ship.😂 That's a great bonus to awesome content! ❤
fridge
Love the print on 1 GHz antenna, havent expected to see it at all. Hello from Ukraine my friend :))
What does it say?
My phone has weak signals I am thinking of making this antenna for a mobile phone, will see if it works 😂
You only can gain so much improvement until the bandwidth needed needs a transmit frequency higher than 2.4ghz
Problem is propagation, you want as low as takeoff angle to have dem waves travel as close to the horizon before they fly out in to space, also one that won't be affected by water vapor, trees, or a building
It's also quite helpful for the wifi access point be at the highest elevation relative to area and devices connected
Then use a 2.4ghz repeater to allow a slower network to fill gaps
Has one here. It just works.
F a n t a s t i c
Really goog Thanks for sharing
the fridge was a visual flashbang haha. Love it
Awesome video! I have been looking for a solution for having an outdoor base station like that. How weather proof is the fridge? Seems like a great solution if you can prevent water ingress.
Been about a year and nothing got inside. Just could use a bit of an extended roof so rain doesn't get stuck on the door
what should the thickness of the helix conductor be??
Have you ever considered trying to build a DIY troposcatter system using cheap C Band LNBs and SDRs?
Do helical antennae couple to the electric or the magnetic part of the field?
What color/ paint is the Fridge station server box ? Looks very "'official"'.
Greetings: I looked in the description 4 the External antenna mod on the router. I could not find by title. Which is it?
*when you finally get tired of losing coverage in your room*
lol
nice build btw
Do you have the stl for the LNB mount? You can see the grey one @3:38 I tried finding on your thingiverse but didnt see it
This is great, and the antenna calculator is really nice! Thank you so much!
I just don't understand how does this relate to the dish. I know how to make a helical antenna, but where do I place it in the dish, how do I calculate the position, number of turns in the antenna, etc. given a dish I have.
you place it with the first (bottom) turn roughly where the entrance of the LNB would be, for standard offset dishes you want around 60-70 degrees beamwidth, for prime focus dishes helical antennas aren't ideal but if you want to use one you need a wider beam such as 90-100
@@dereksgc Thank you so much I understand now. I will get images from the Metop satellite even if is the last thing I do!
Another nice vid with good data thanks again
Super informative video. What kind of cable would you use for connecting the router to the antenna?
I forget the cable type atm but it's that small clearish tan stuff you use with sma / rpsma fittings, also since consumer wifi devices are not powerful you definitely want the cable run to be 50 ohm impedance, as short as possible with no tight bends, kinks or adapters and NO loops.
The BEST option for a good wifi antenna is actually not an antenna but a wireless bridge radio set in client / station mode and used as an external high gain high power wifi adapter on your PC laptop. literally all it uses is a set of ethernet cables to interface it's PoE injector (power supply) inline to the radio and from your PC / laptop. Plant it on a tripod outside facing the direction your desired wifi signal is in and the rest is web based setup and connecting.
this is great, please show us the 5 Ghz version!
Hey Derek I’ve been trying to design a helical for some time but I’m struggling with it. I know you said you eyeballed it and don’t care but how did you come up for the dimensions of the matching strip? I can’t find details of this online:( thanks
Should try an iperf test to check it's try throughput
So how did you measure the VSWR and what was it?
a really nice one! RSN PZD!
awesome work bro. just inquiring incase we have two helical antennas for example lets say using this very one for 2.4 ghz, and we have them said by side but have them connected to the same cable feeding to the adapter will it improve on the reception stregthen or will it degrade instead
You would have to use a proper phasing network to make sure the two antennas actually work together instead of against each other. It can be done but it is much more difficult than just making a single helix a bit longer
Now what's the 5 ghz WiFi helical antenna construction look like?
At what cable length do you use, you lose at least -3 dB. It is ideal to use a thicker and shorter cable. 1dB maximum loss with LCF1/2, but the disadvantage is that it is rigid and the plugs cost more. But you can use longer lengths, compared to thin cables. I use at least LMR400, 1/2 and for longer cable lengths type 7/8...
Fuck! Now I want an Antenna Fridge too!... But first I need a garden :-/.
Also I love this DIY video with the simple but very complete explanations and considerations.
Btw, what kind of antenna is on the other side? a normal wifi router or an other helical antenna in the same turning direction?
I guess corrosion might be a problem, because it no aluminum (some epoxy for the copper might help).
Maybe next time you wanna try a quadrifilar helicoidal antenna ;-)
If I wrap the copper wire in helix, around a 3D printed PLA tube, which has a pre defined grove in helical form, and super glue them together and keep that tube attached to the dish. Will that effect the gain of the antenna.
It is probably going to work, that is how I made my very first helix as well, but I can't say how different types of PLA may affect the helix
@@dereksgc put a sample in a microwave oven (and a cup of water). the hotter the sample gets the worse it is for RF use
Is stripping the plastic off the wires necessary if there's no shielding to get in the way? Might improve the outdoors longevity
It most likely would be fine, but it removes one uncertainty factor. Each insulation may have different dielectric properties and a different effect on the antenna, but as I've demonstrated in the video helical antennas are so forgiving when it comes to design changes it probably would still work
Hey can you use this Helix with the dish? And what distance are you covering and lastly is it line of site? Will trees cause a lot of interference?
A dish feed should probably have fewer turns. I have several other helical antennas like this for various frequencies as dish feeds. 2.4 GHz WiFi will always be heavily affected by obstacles. In my case I'm only covering about 100 meters, but with trees and walls in the way. If you had a perfectly clean line of sight I'm confident you could achieve many km/miles of range
Quick Question: I really don't have any scrap yards near me and I'd need to buy one online. Would a copper sheet or aluminum sheet be suitable for such use? And if not, what would I need to search after? And what would be the measurements for a 1.7 GHz Antenna (diameter, thickness)? Thanks!
You can use this calculator to give you the dimensions based on frequency, you can also scroll down to read about some of the values and design choices: sgcderek.github.io/tools/helix-calc.html
If you can't get a sheet of metal, you can use any flat square/circular metal object, for example some of my antennas use the bottom of a large tin can cut out. A more unusual but still perfectly valid solution would be getting a metal dog/cat bowl, as long as the center is flat enough and large enough
That looks like a lot of copper for 2.4 GHz. In a tank circuit, that would most likely be under 30 MHz somewhere. Have you connected this to a spectrum analyzer to see where it's peak is? Maybe I missed something?
not this exact one, but similar antennas I've made did have a resonant peak around 2.4 GHz, sometimes slightly higher or lower but they are wideband enough for that not to be too much of an issue
Helices actually have two radiation patterns, depending on the dimensions you choose.
If the circumference is much smaller than a wavelength and the pitch is much smaller than 1/4 wavelength, then they do act like a dipole, with an omnidirectional "radial" pattern, perpendicular to the axis of the helix.
But in this case, it's a directional ("axial") helix antenna, where instead the _circumference_ of the helix is proportional to the wavelength, and the number of turns affects the directional gain. Then, the maximum gain is in the same direction of the axis of the helix.
The Wikipedia for "helical antenna" goes into more detail about those two modes.
amazing video! i was comparing my results with your calculator and i think there is an error in the Half power beam width, the First null beam width and the Gain. Bhp = 52/[ (C/lambda) * sqrt( n * (S/lambda) ) ] , Bfn = 115 / [ (C/lambda) * sqrt( n * (S/lambda) ) ] , G = 11,8 + 10 log [ (C/lambda)^2 * n * (S/lambda)]
thanks for the heads-up, theres already one issue been opened on github about this, i've been putting off a complete overhaul of the website so i will try to get this fixed up during that
great video man
so i need 1700L or 1700R with dish reflector for NOAA HRPT?
HRPT is RHCP, but dish inverts polarization, so you need LHCP
The file you linked to doesn’t have the same base that attaches to the reflector, could you please post the exact one you showed on your video?
Solved by changing the paameters around n the code, sorryabout that this is the first parametric (?) design I've encountered!
If you have a multi antenna router to connect these ones to, would it make sense to make 1 left polarized and 1 right polarized?
Probably, that way the router can work with the inverted polarization reflections. Left vs right hand polarization is for circular antennas more or less the same thing as vertical vs horizontal for linear, which is what MIMO antennas tend to use anyway
@@dereksgc all that destroys the function of MIMO, it's about getting the relative time-of-arrival of a valid signal and filtering out signals with a different time signature. the best information i can find for this is that the two antennas need to be a half-wave apart
Bro what is the name of the tool you are using in this video to cut the metal sheet? I never seen it before
it's just a normal manual sheet metal cutter
I think that a metal lid for a 1 gallon paint can would work fine for the reflector.
yep
Is there a video where you show how you modified the router?
No, that happened before I was really making videos. But it looks like I'll have to do that again once I get a dual band router to test 5 GHz so I'll probably record that
I have question for this video, in sessions performance setting, you made antenna helix for transmitter or receiver? I need answer from u, sorry for question 🙏
In the video when I was testing the speed, the helix was aimed at a router with a standard whip antenna, so you could say the helix was at the "receiver". Router with helix was getting internet connection from a router with normal antenna far away
@@dereksgc okey thanks for answer, Do you think this antenna could be possible for transmitter communication WiFi?
@@MONEYCONCEPT27 it could but it is not omnidirectional, only works well when pointed at things directly, and may violate EIRP power limits depending on your country
@@dereksgc I plan to design an antenna for WiFi communication as a transmitter, do you think a helix antenna or a microstrip antenna is better? I ask for your advice
You should use something like iperf so you remove the internet as an issue. You can run a server at the base location and a client on your laptop
How does it affect signal of your neighborhood?
It doesn't
Change patch antenna to biquad antenna, higher gain but also better directivity. Then compare with the helix antenna...
Hi Derek, I noticed the helix_v5 models' default is 1700L, and not the 2450R that is in this video. Is it possible to have the values you used in the video posted in the description so we can use your calculator to edit the values in OpenSCAD? A thousand thanks! :)
After using a larger display, I could see that you included the proper values in the video (I just needed to look closely at a screenshot). Thank you! 🏆
On a side note: it looks like the bottom strut offset is placed at a value of 25 instead of 0 as shown in the video. Everything else looks correct, I think.
You can use the offset to lift the bottom strut if if gets in the way of the connector or anything else, besides the frequency+polarization, number of turns, and turn spacing, most other values don't actually impact the performance of the antenna itself
question, for this setup do you use both helix antenna on each end? i mean from that station to your house?
no, other end is just a normal router behind a couple walls, this one helix is having to do all the work on its own
I was under the impression that helical could receive linear just as good as a linear antenna would. It would just pick both H and V at the same time.
linear will receive a circular polarized signal just fine, this is how many FM broadcast stations are set up so your stereos linear vertical whip / telescopic or horizontal dipole wire works.
The thing with circular polarization is they work best in systems with "moving parts" like FM broadcast transmitter is static but your vehicle is not or an orbiting satellite is moving (tumbling) or not in geo where you may be static or moving around via car, boat, plane.
hello say i needed to make one for digital TV to mount on a dish what wave length is that
This will not work well for TV, the wavelengths are too large, you will have to look up your local channel frequencies but they tend to be between 500 and 1000 MHz, a helix would not be practical. If you have a very large dish antenna (2m or more) you can use a yagi antenna in the focal point, otherwise you are better off just building and using a normal yagi
Thanks for this it has cleared the confusion so for the tv channels the Yagi antenna will best option i wll give that short i have made some yagi before. @@dereksgc
So for the point to point you only have the one helix at the ground station? Or is there a second antenna pointed at your fridge setup from the house router?
I only have one helix because the other router needs an omni antenna to cover the entire house, which means the performance is much worse than what it would have been with two helicals aimed at each other
I'm impressed it got such decent performance and that's good to know. The video was very well made btw good job
If you have two of these with different chirality can you do MIMO? Is there something like a disk-yagi that would get you radial polarization so you could get 3 streams going?
Not sure how well MIMO would work with a directional antenna. If a circular signal reflects off something it inverts its polarity, so having both LHCP and RHCP could interfere with itself.
@@dereksgc if you used wifi5/6/7 with 2x2 mimo, with matching polarization on the 2 sockets, the router would be able to better ignore other signals/noise on the band increasing it's effective range much further. there are extra options not enabled by default in openWRT regarding this. obviously this would involve two dishes at each end, but plain helicals + mimo is awesome for point to point
@@timothius9000 Yeah absolutely, LHCP/RHCP MIMO would be the ideal solution, I just wanted a straight test of one antenna vs the other considering that they both promised more or less the same gain. One issue that comes to mind is dual-band operation on 2.4 and 5 GHz, the helix might not be very suitable for that, though there are dual-band helical antenna designs that have been proposed
you'd be better with devices that have 4 antenna sockets, 2 x (2x2) mimo (and 4 helical antennas looking like an array)
is this antenna bi-directional ? if not, whats thue use ?
It is, antennas receive the same way they transmit, as long as they can handle the transmit power (which in case of 2.4 GHz WiFi hardware is basically nothing)