mavic mini yagi antenna (CE)

[Ronny St.]

Thanks. For practical reasons, those lengths may be too cumbersome, so could an exact fraction be used instead, e.g. ½ so 6.25 cm and 2.5862 cm respectively? It appears that’s what the yagi antennas you can buy online have done. Also, the one at the back appears to be longer for both 2.4 and 5.8?

Finally, what should the distances be between them?

Well, as I wrote before, it is more complicated as the basic equation if your really want to make an optimal Yagi. This equation goes only for one element, called a dipole. You must know that only one of the rods is the dipole antenna, the other rods are for reflecting and directing the waves generated by the dipole element.



More directors make a more complicated total wave pattern. I refer to some interesting websites with information on Yagi antennas and for online calculating the exact lenghts and spacings of the rods for a 3-element Yagi: 3-element Yagi calculator or yagi antenna or more info on Yagi. If you googlo on 'Yagi antenna' you will find numerous websites on the subject.
The spacing of the directors D3-D4 etc is usually the same as for D2-D3 since the effect will be less and less the further you go from the dipole element, but the first 3 have to be spaced at a different distance from each other. You see that making a Yagi is a lot more that just putting some rods together... And I have not mentionned skin effect of the thickness and the metal used etc. If you buy a Yagi you can only hope the manufacturer has done his homework properly.

I hope I did not make it too complicated but I think I have proved that antenna design is not an easy task

 

[mike.alexander]

I hope I did not make it too complicated but I think I have proved that antenna design is not an easy task

Thanks, I was hoping for a simple answer, but (like many things in life) it’s more complicated that you’d hope! I think I’ll just buy one online and, as you say, hope they’ve done their homework.

 

[GerdS]

Just look at ready-made designs such as available on Thingiverse.com, e.g. Mavic Mini Yagi antenna adapters (range booster) 2.4 & 5.8Ghz by cylllka. I have built these by myself and made good experience yet with both types of them.

 

[Ronny St.]

Just look at ready-made designs such as available on Thingiverse.com, e.g. Mavic Mini Yagi antenna adapters (range booster) 2.4 & 5.8Ghz by cylllka. I have built these by myself and made good experience yet with both types of them.

Well, that is a link I did not find before: thanks for submitting it! I am even now considering of building it for myself to do some experiments

 

[mike.alexander]

Just look at ready-made designs such as available on Thingiverse.com, e.g. Mavic Mini Yagi antenna adapters (range booster) 2.4 & 5.8Ghz by cylllka. I have built these by myself and made good experience yet with both types of them.

Yes, I’d seen these online previously. My daughter has a 3D printer, so I could ask her to make them for me. However, seeing [mention]Ronny St. [/mention]’s detailed knowledge, I wondered if the lengths given in the link you provided (the third and fourth photos) were 100% correct for each frequency.

[mention]GerdS [/mention] What material did you use? Aluminium or copper? I’ve read elsewhere that copper may be slightly better, but there’s no major advantage over aluminium.

 

[GerdS]

I don't think that the material of the rods has much influence. If I would have been able to get aluminium rods I would have taken these. But in my stock was a 1m brass rod with matching diameter, so I took this. Only disadvantage, the antenna is more heavy.

 

[PRO>KOMP.<]

I got with yagi max 4200m distance with CE version. I record it and I will upload on YT whole flight. Right now I test yagi vs reflectors vs stock antennas if someone what to look here is link

 

[Ronny St.]

Yes, I’d seen these online previously. My daughter has a 3D printer, so I could ask her to make them for me. However, seeing [mention]Ronny St. [/mention]’s detailed knowledge, I wondered if the lengths given in the link you provided (the third and fourth photos) were 100% correct for each frequency.

[mention]GerdS [/mention] What material did you use? Aluminium or copper? I’ve read elsewhere that copper may be slightly better, but there’s no major advantage over aluminium.

On youtube I found this video which concludes there was no difference between copper and aluminium : copper vs aluminium rods on a yagi for the MM

 

[GerdS]

On youtube I found this video which concludes there was no difference between copper and aluminium : copper vs aluminium rods on a yagi for the MM

The function of the antennas depend on conductivity of the rods, not of the material they are made of.

 

[Ronny St.]

The function of the antennas depend on conductivity of the rods, not of the material they are made of.

Indeed, but the conductivity if aluminium is 0,4 megamho/cm and that of copper is 0,6 megamho/cm where mho stands for 1/ohm. It has, however no or little effect on the rods in a Yagi-antenna of the size we are talking about here.

 

[tmse]

how about the CE types?
Do the need one 2.4 GHz and one 5.8 GHz?
And on witch one, 2.4 on the left en 5.8 on the right or twisted?
And don't forget the velocity factor of the material!
And how about the original antennas, is the impedance still 50 Ohms?

 

[slup]

how about the CE types?
Do the need one 2.4 GHz and one 5.8 GHz?
And on witch one, 2.4 on the left en 5.8 on the right or twisted?

Always useful to read through a thread from the beginning ... see post #3

 

[tmse]

I understand that the controller sends 2.4 GHz and the drone sends 5.8 GHz.
Or am i wrong?
So i need 2 antennas one 2.4 and one 5.8 GHz!

 

[RogerDH]

Indeed, but the conductivity if aluminium is 0,4 megamho/cm and that of copper is 0,6 megamho/cm where mho stands for 1/ohm. It has, however no or little effect on the rods in a Yagi-antenna of the size we are talking about here.

Also, oxides forming on the elements' surfaces will reduce their conductivity, and aluminum oxide is more conductive than copper oxide, so any advantage copper elements might initially have won't last long.

 

[Droning on and on...]

I bought some 2.4ghz yagi antenna's from ebay. The quality clearly isn't very good as you can see from these two pictures where I rotate one of the yagi antennas
Yagi2 Sticker GIF | Gfycat

I had read somewhere that the yagi antenna's should be mounted approximately 28 millimeters below the tip of the antenna's.
With these poor quality antenna's I bought, the middle of the metal rods is located only 24.3 millimeters from the tip of the antennas.
Is it correct that it should be 28mm?

 

[GerdS]

I bought some 2.4ghz yagi antenna's from ebay. The quality clearly isn't very good as you can see from these two pictures where I rotate one of the yagi antennas

I guess the frame has been 3D-printed with PLA and PLA does not tolerate temperatures above about 50°C and will deform quickly. Maybe that has happened during transport. It can also happen in summertime when leaving them within a car for a while.
For avoiding this, I have 3D-printed my sets out of PETG, which is much more resistant against higher temperatures.

Maybe you can fix it by using a hair dryer for heating up a bit and then bending back.

 

[Droning on and on...]

Maybe you can fix it by using a hair dryer for heating up a bit and then bending back.

I did a test and got to 3668 meters (CE model obviously), so I guess I won't mess around with bending the antenna's as the results are good. With the 5.8ghz yagi's I can't get further than 2200 meters. Although I'm not sure how high I should mount these 5.8ghz yagi's from the top of the antenna (they are the fancy silicone type that you can mount at any hight)

 

[fificap]

The function of the antennas depend on conductivity of the rods, not of the material they are made of.

Hi,
Do you think i can use copper rod made for soldering?

 

[Pushkur]

I got with yagi max 4200m distance with CE version. I record it and I will upload on YT whole flight. Right now I test yagi vs reflectors vs stock antennas if someone what to look here is link

Out of curiosity I tried a flight in 5.8 using the 5.8 silicon yagi's with a set of parabolics also attached?
Flying over a semi rural terrain,that most definatly has WiFi interference,my previous max distance was 3,600 meters,using just the yagi's.
Today adding the parabolic to the mix I reached 4,000 meter.
Mini is CE, but I fly it hacked in FCC mode.
Need a few more try's over same flight path, before I can confirm they work well together.
Be interesting to see what can be achieved trying this far from any interference,both in 2.4 and 5.8.
Anyone else tried this mix,can't see any on You tube,only comparisons.

 

[fificap]

Out of curiosity I tried a flight in 5.8 using the 5.8 silicon yagi's with a set of parabolics also attached?
Flying over a semi rural terrain,that most definatly has WiFi interference,my previous max distance was 3,600 meters,using just the yagi's.
Today adding the parabolic to the mix I reached 4,000 meter.
Mini is CE, but I fly it hacked in FCC mode.
Need a few more try's over same flight path, before I can confirm they work well together.
Be interesting to see what can be achieved trying this far from any interference,both in 2.4 and 5.8.
Anyone else tried this mix,can't see any on You tube,only comparisons.

See that: combinaison of parabolic & yagi