Yagi antennas (adapters)

[niki]

Yes they did. Do you know that the patch antenna is not just some clip-on gismo but an actual wired connection. Why? Because that's how real antennas work.

Your arguments are siply not in place. Looks you don't have an idea how 3 element yagi uda antenna works. There is nothing wrong in that we all learn whole life.

Here is a short explanation if you or anyone that states this yagi uda adapter need to be connected to a wire. The adapter provides the "reflector" and "director" elements while the "dipole" element (the active one that's connected to a wire) is the RC's antenna itself. It's so simple for those who understand how does yagi and other type of antennas that use parasitic elements by design are working.

"The yagi antenna's basic design is a "resonant" fed dipole with one or more parasitic elements. These parasitic elements are called the "reflector" and the "director." A dipole will be "resonant" when its electrical length is 1/2 of the wavelength of the frequency applied to its feedpoint. The yagi-uda array can be summerised by its performance considering in three parts Reflector Feeder or dipole director The length and spacing of the reflector do affect the forward gain but have large effects on the backward gain (F/B ratio) and input impedance (Zin). Thus they can be used to control or optimize antenna parameters. The driven element is typically a λ/2 dipole or folded dipole and is the only member of the structure that is directly excited -electrically connected to the feedline. All the other elements are considered parasitic. The feeder length and radius has small effects on the forward gain but a large effect on the backward gain and input impedance. Its geometry is usually chosen to control the input impedance that most commonly is made real (resonant element)."

https://www.researchgate.net/figure/3-Element-yagi-uda-beam-antenna-The-yagi-antennas-basic-design-is-a-resonant-fed_fig1_280557075

So if one spent time reading this will realize that the adapter contains all "parasitic" elements while the dipole antenna comes from the RC. When they are combined the result is yagi uda antenna

 

[Dave Pitman]

Your arguments are siply not in place. Looks you don't have an idea how 3 element yagi uda antenna works. There is nothing wrong in that we all learn whole life.

Thanks for the link. It says that only one element of the yagi is driven (wired) which in this case is the stock dipole. By that it looks like it could work. Thanks for being persistent. I did learn something!

Yagi–Uda antenna - Wikipedia

en.wikipedia.org

 

[Dronelover]

Your arguments are siply not in place. Looks you don't have an idea how 3 element yagi uda antenna works. There is nothing wrong in that we all learn whole life.

Here is a short explanation if you or anyone that states this yagi uda adapter need to be connected to a wire. The adapter provides the "reflector" and "director" elements while the "dipole" element (the active one that's connected to a wire) is the RC's antenna itself. It's so simple for those who understand how does yagi and other type of antennas that use parasitic elements by design are working.

"The yagi antenna's basic design is a "resonant" fed dipole with one or more parasitic elements. These parasitic elements are called the "reflector" and the "director." A dipole will be "resonant" when its electrical length is 1/2 of the wavelength of the frequency applied to its feedpoint. The yagi-uda array can be summerised by its performance considering in three parts Reflector Feeder or dipole director The length and spacing of the reflector do affect the forward gain but have large effects on the backward gain (F/B ratio) and input impedance (Zin). Thus they can be used to control or optimize antenna parameters. The driven element is typically a λ/2 dipole or folded dipole and is the only member of the structure that is directly excited -electrically connected to the feedline. All the other elements are considered parasitic. The feeder length and radius has small effects on the forward gain but a large effect on the backward gain and input impedance. Its geometry is usually chosen to control the input impedance that most commonly is made real (resonant element)."

https://www.researchgate.net/figure/3-Element-yagi-uda-beam-antenna-The-yagi-antennas-basic-design-is-a-resonant-fed_fig1_280557075

So if one spent time reading this will realize that the adapter contains all "parasitic" elements while the dipole antenna comes from the RC. When they are combined the result is yagi uda antenna

 

[Dronelover]

Niki. After 40 years of ham radio and experimenting with yagi and phased arrays you are perfectly correct in your posts and statements.Now I just need to find a manufacturer of the Yagi for the Mavic pro for 2.4 ghz . Any suggestions?

 

[Dronelover]

How do yo explain the gain in distance that the people are getting with those?

 

[Dronelover]

Thanks for the link. It says that only one element of the yagi is driven (wired) which in this case is the stock dipole. By that it looks like it could work. Thanks for being persistent. I did learn something!

Yagi–Uda antenna - Wikipedia

en.wikipedia.org

 

[Dronelover]

The reason the distance is improved is because they work like any other Yagi and the driven element (which is what's known as a dipole and a 1/2 wavelength long) is the only element of the Yagi that needs to be hardwired into the control unit. The remaining elements use their length and spacing on the Yagi to either reflect or direct the signal and are what is known as phased elements. Obviously the more elements on a Yagi the more directional it will become. My experience in the past has been with antennas for 3.9 MHz where the driven element would be over 120 foot long at 1/2 wave and over 50 feet long at 1/4 wave and I was able to use an oscilloscope to measure the phase difference between the different elements on the antenna and subsequently optimise them for maximum performance using a home brew phase unit that adjusted the phase angle using adjustable capacitors and inductors to obtain the correct phase angle which is done on a Yagi antenna by adjusting the element lengths and spacings. Comparing a Yagi with a parabolic style antenna then the parabolic antenna will only act as a reflector and not a director therefore the Yagi should score way above as it not only contains a reflector ( the element behind the driven element) but directors also that are placed in front of the driven element.

 

[Dronelover]

Oh, never seen those before. But a Yagi is an antenna, in order to work it has to be wired to the antenna emission output. Just sliding those on is pretty much useless.

Wrong The Elements of a YAGI do NOT have to be wired to any part of the antenna or control unit and will produce gain not seen on anything out there on the market so far as a Yagi not only has a reflector same as the parabolic range extenders do but also directors that narrow the pattern of the Yagi in one direction and increase the gain of the antenna in one direction.

 

[niki]

Wrong The Elements of a YAGI do NOT have to be wired to any part of the antenna or control unit and will produce gain not seen on anything out there on the market so far as a Yagi not only has a reflector same as the parabolic range extenders do but also directors that narrow the pattern of the Yagi in one direction and increase the gain of the antenna in one direction.

Thanks for your comments!
I was hoping to get some constructive discussion here about those antennas but it looks this forum with its curent active members don't have the capacity of making a such or at least the most active members act like this. It's so dissapointing to see peoples ignorance and willing to say a statement on matter they do not fully understand. This simply lowers the authority level of the forum. People should stay open minded for stuff they dont fully understand otherwise they will never learn it. This realy adds confusion, noise and even disinformation toward that specific matter as well many other threads in this forum. There is so much more information about yagi uda antennas and adapters on the other forums like mavicpilots and rcgroups.

 

[Dave Pitman]

I was hoping to get some constructive discussion here about those antennas but it looks this forum with its curent active members don't have the capacity of making a such or at least the most active members act like this. It's so dissapointing to see peoples ignorance and willing to say a statement on matter they do not fully understand. This simply lowers the authority level of the forum. People should stay open minded for stuff they dont fully understand otherwise they will never learn it.

Speaking for one of the skeptics that I assume you are referring to, you did notice that I acknowledged my misunderstanding of the Uda-Yagi design. This was of course after you posted links to the concept of the Yagi and not just anecdotal evidence of performance gain, big difference.

Just because the others that were skeptical didn't chime in, that doesn't mean that they are closed minded.

So, for discussion, a yagi antenna is very directional and as such is not a great candidate for long range uas operations unless the operator can know for a certainty the direction of the uav. While providing increased range, it also lowers the range unless the antenna is strictly aligned to the craft at distance which can be a challenge. They are so directional, that they are often used in wildlife tracking because they are so easy to get OFF of target and thereby give a more clear direction to the transmitter when ON target.

I guess it's use could help out when flying in high interference environments, if you have that problem, where you can actually see the aircraft (you know, like you're supposed to) and therefore easily point the antenna at it.