How to build your own DIY Dipole 868 Mhz (LORA - Meshtastic)
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- Опубліковано 30 січ 2024
- How to build your own DIY Dipole 868 Mhz (LORA - Meshtastic)
This video is a DIY tutorial to build your own 868 Mhz dipole antenna with excellent VSWR, to use for your Meshtastic nodes and/or LORA devices.
Link to download the 3D case stl file : go to printables and search for "749479-dipole-antenna-support-case" (youtube does not allow to paste a link)
Just build this dipole antenna, and tuned it with my NanoVNA, getting a SWR 1.4. And holy crap, that improved things.. Using a T-Echo and that factory antenna is for the bin now.. Can see a node 600m away, and that improved from RSSI -115 to -94, and in indoor bad inviroment.. So i need need to make another now, and run more tests.. I'm hooked :-) Thanks
Great !
Hello, I have really enjoyed these videos as I am very new to Meshtastic operations and I am preparing to build some of these dipoles. These are good videos as they are direct and to the point. Thank you.
Remerciements pour ce video. Just what I was looking for.
That's nicely done, TY!!!!!
Brilliant tutorial, thanks so much :)
Great video!
Excellent, thank you for sharing :)
thx
Excellent video
Merci! Tres bien! Very good info!
To straighten the wire, grip in the vice and pull with pliers until you feel it yield. No need to spin it, and the wire becomes perfectly straight.
can work too but more difficult to have enough strength to pull straight. Using the rotating power of the drill is no effort.
@@PoweredMeshtasticEurope True. I can pull up to 16SWG, but that's my limit.
@@PoweredMeshtasticEurope First of all, great video, thank you for posting. I do have a question, is there some way to "strengthen" the antenna, maybe some sort of PVC tubing etc just to make it more weather/wind proof?
For waterproofing liquid rubber works great. It ist not as viscos as silicone and it it is easier to remove
Merci
Great ½ wave antenna.
Great video well done 👍🏽 73
Thanks for the tutorial. I'm fed up paying good money for bad antennas.
I'm sure you know already but you can up the resolution on the nano by going.
Stimulus, cfg sweep, sweep points.
I think that model can do 1000.
Thanks I'll try !
Excellent video. Im off to go make a couple for mine. You dont have to strip the entire wire, i would cover the exposed ends with some silicone to keep the wire water tight. Thank you. Subscribed
73s VE6RFL
Thanks for this video.
Can you do a test field compare with other antenas like the original that cames with eltec lira v3?
I keep your suggestion in mind for an eventual future video. Thanks
Thank you very much for this video, it is very helpful. I ordered the cable to make the antenna as you described. And, I also ordered the antenna diagnostic (NanoVNA-H 4). I can see you are an expert. Could you please prepare a short tutorial on using the NanoVNA device. For people like me, who are new to the field, to me, it is not clear what the numbers you mentioned means and where are they located on the screen device, and what sort of graph to look at. Thanks in advance. Have a nice day!
Nice of you. I'll see if I have time to make a tutorial on using Nano VNA but you can already find lots of these tutorials from others on youtube. This is how I learned myself...
A very useful video. Isn't a dipole 75 ohms when resonant, so 1.5 SWR is about right.
a resonant dipole presents 50 ohms of impedance
Nice video. I purchased 2 Heltec ESP32 v3 today which use the ipex connector. So for these you would cut off the sma instead.
Thanks for your comment. The pigtail which is delivered with the Heltec V3 is not a very high quality coax. I would suggest using a pigtail such as shown in my video instead. But technically you could do what your saying.
Any Recommendations how to tune it as NanoVNA comes with SMA i.e. is there suitable ipex-SMA adaptor that would allow tuning antenna that has ipex connector at the transmitter end?
Very good and informative video! I am going to build some an see if I can increase my range. I have bean looking at pigtails for this and I have two options for coax RG178 and Rg400 woud the RG400 be stiffer? Is it ok to use it? Or might I be better off using a tube on the outside of the coax to stiffen the antenna? (we have a lot of winter in my area and I am afraid the coax might be damaged over time with the constant bending)
I have personally stiffened the coax with a simple piece of electric wire (taped).
3:00 I just use two pairs of pliers, a little tug and a twist
I would only tune the antenna after installing it on its final location.
Anything in close proximity around it affects the tuning, even the mount, where you secure the 3D printed part will.
The heat shrink tubing is a way to UNDO too much cutting 😂
could be done but would require to move the Nano VNA on site
Or at least have the antenna in "free space" and not lying on the table. The proximity to whatever that material is in the near field will have an effect.
Also the wire cutters you have appear to be rated for 1mm max cable or so it appears. If you keep using them for larger stuff they are likely to break and take your eye out. Its happened to me twice now, thats why im replying to you on my braille touch screen tablet which works wonders.
I'm assuming ive typed this in the right place?
sorry to hear what happened to you. Thanks for the advice.
@@PoweredMeshtasticEurope Hah, while funny, he is right to some degree. I don't think your wire will cause it to break, but they can and DO, especially if you try to cut harder wire than copper, or larger diameter. They are little electronics nippers meant for .5mm and smaller. Trying to cut some like 6awg stranded wire might work, might break them. That's how I broke a set of my xcelite cutters. And when they DO break, it might be just the tip, might be a whole jaw! All that force goes somewhere, which ends up being turned directly into kinetic energy imparted on the part that breaks off. Which can make it move quite quickly, easily more than enough to pierce skin, or take an eye out.
That's the same reason why it's extremely important to constantly 'dress' your punches and chisels. The end you hit with a hammer mushrooms out, and eventually a fragment WILL break off, and the entire force of the hammer hit shoots them out like a bullet! Same thing applies to these little cutters!
I am just making up one of these, and appreciate the video. However i wanted to check, the antenna is always shown with the radiant element horizontal. Should these not be vertical or the pattern will be emitting its longest range and strength vertically instead of horizontally? Just thought this might be good to mention. I tried putting a bend in my Very heavy Pigtail to change the axis and its throws the VSWR off by a full point. Really amazed at home much difference having it sitting anywhere another object makes. Antennas really are an art form almost as much as a science.
Yes, the dipole emits as a flattened donut shape around the radiating elements, so you have to have the feeding cable horizontal and the radiating part vertical. Any addition of a capacitive or reactive objects to the antenna will modify its characteristics. Any addition of connectors will also increase the losses (I believe +3dB loss per additional connector)
Thanks for the confirmation. Got mine to 1.4svwr at 48ohm. Tried a couple of times to get below 1.4 but couldn’t seem to quite get there before it started going back up.
@@mostlysane77 That is pretty good and will already be a huge improvement over off the shelves antennas
is the length of the vertical wire not part of the total length or should we consider the coax non receiving
?
The coax does not "receive" (but is part of the circuit). Ideally the coax part should be 1 wavelength (1/2 wavelength is also ok. Other multiples will generate reflections). In practice it is difficult to have it tuned perfectly (there are so many factors : quality of the dielectric, thickness of it, impedance, reactance, etc).
Great video, STL file has only one side/panel ? "749479-dipole-antenna-support-case". Did I miss something?
print two
Omg really 😂
Can I ask, is there a reason you strip the wire and then cover in heat shrink? Just wondering if it performs better than with the original insulation.
Yes ! The stripping i required to straighten the wire. Then The heatshrink will protect (against oxydation) and stiffen the wire.
@@PoweredMeshtasticEurope Thank you for replying - that makes complete sense👍
Can copper welding rods be used instead of wire?
sure. But thickness will have an impact. In fact the thicker, the broader the bottom of the VSWR curve but not as deep. So you can choose to have a broader range antenna but not as good VSWR or a better VSWR with narrower bandwidth.
Hi, great video. I would like to make one of this for 915MHz antenna LoRa. Should I use the same method? Thank you very much.
Yes sure, except you have to adapt the length of the two radiating elements in function of that 915Mhz frequency range (rule of 3 will work)
@@PoweredMeshtasticEurope And I should reduce the size of the coax wire a little bit. Thank you very much.
@@anlpereira the coax wire's length is not so important.
@@PoweredMeshtasticEurope thank you very much.
Could you build a helical directional yagi for band?
I would have to research these antennas a bit
That would be great
Do you have a link to the 3D print file for the dipole centre?
I have updated teh description with the link to printables to download the stl file.
Thank you!@@PoweredMeshtasticEurope
Can you show good 2.4Ghz antenna design?
If I find the time for it. But basically , divide all lengths by 2.76 (ratio between 2.4Ghz and 868 Mhz)
You are going from unbalanced line (coax) to balanced (dipole). Isnt balun required? Also 50 to 75 ohm is not the best match, as shown on vna
You're right. Ideally you should have a balun to get a perfect impedance match, without any reactance (capacitance or inductance). But this is out of reach of the common tinkerers and it works weel enough with that simpler approach.
Execuse me do you have pang ing problems?
Not sure what you mean ?
Does anyone sell these ready made that are correctly tuned for 868?
I do not know of anyone. But really you could build it yourself, you're capable !
Use the base of the useless Antenna that comes with the device, just cut off the centre conductor... and add your design
Yes, any coaxial feeding line does the job indeed (coax needs to be thick enough though for minimum losses)
SWR 1.0 doesnt mean "all energy is emmited". No!
What's your definition ?
@@PoweredMeshtasticEuropeHard to descibe without some background in physics. Pure resistor 50 Ohm has SWR 1.0, emits RF energy zero (but heat)
@@PoweredMeshtasticEuropeen.wikipedia.org/wiki/Standing_wave_ratio
Oh my. Antennas are rarely a simple 50 ohm resistor.
Very good share for DIY , thank you. VY73 de BD7PA