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Yagi - Do they Work? FCC
7271 33 2020-6-3
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ABeardedItalian
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My Yagi's finally came, weather hasn't been so nice but I tried to get out and make a video. I've had a second chance to test off video and have had similar results and can conclude they do help but I wouldn't rush out to get them. I want to play with them a little longer, see if I can't make any improvements before I make any final review but I thought I would share my early findings.



2020-6-3
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Geebax
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Australia
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Anyone who is into amateur radio and/or building their own antennas will tell you those yagis are never going to produce miracle results, as antenna design is extemely precise, and the higher the frequency, the more precise they become. And you are adding them to an antenna on the RC that is probably designed to work very well on its own, not have spurious lumps of aluminium hung off it.
2020-6-3
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raven swe
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Your Right There Geebax,  SA4MDN
2020-6-3
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DAFlys
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Seems like a nice little improvement.
2020-6-4
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raven swe
Captain
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so does sending the drone higher, within the rules of course,
2020-6-4
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bjr981s
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Total waste of time. The controller end TX of the RF Link is not the issue. It's the backchannel in the drone. Drone Tx to Controller Rx.

Yagis are used for Transmitters. Ie TV towers. The lengths  have been custom cut to be precise for the TV channel frequency. I think normally 1 wavelength. And a number of them to handle the power output from the RF amplifiers.

They are "suboptimal" receivers.

There is available the dual convex range extenders. They do work. Not because they boost the TX signal but the convex shape acts as a lens to focus the RX signal back from the drone. They are also wavelength independent so fine for 2.4 and 5.8 ghz. Think of what a radar dish or satellite dish looks like.

Anyhow I would be cautious testing your Yagi array.

Cheers

   
2020-6-4
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Balooo
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Thank you.. you're the first one to test it on the same track and altitude (from what I've found).. great
2020-6-4
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Woe
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Thanks for sharing.
2020-6-4
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USS ENTERPRISE
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drone                        FCC
2020-6-4
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Hotrod in Daytona
lvl.3
United States
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Wondering whether modding the drone to extended the antenna through the body with a wire would improve the range.  Having a wire out the bottom of the drone would mean which way the drone is facing wouldn't matter to reception nor transmission.
Back in the day, taking speaker wire and attaching it to the rabbit ears and then running it to the windows improved reception.
2020-6-4
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itchyeyeballs
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bjr981s Posted at 6-4 03:52
Total waste of time. The controller end TX of the RF Link is not the issue. It's the backchannel in the drone. Drone Tx to Controller Rx.

Yagis are used for Transmitters. Ie TV towers. The lengths  have been custom cut to be precise for the TV channel frequency. I think normally 1 wavelength. And a number of them to handle the power output from the RF amplifiers.

I'm not an expert but there are some compelling videos on Youtube showing positive results.

Most seem to be precision 3d printed to match a specific frequency 5.8 & 2.4 look very different.

As for the Yagi not being a good receiver, almost every tv reception antenna I've ever seen seems to follow the same principle
2020-6-4
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120ccpm
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bjr981s Posted at 6-4 03:52
Total waste of time. The controller end TX of the RF Link is not the issue. It's the backchannel in the drone. Drone Tx to Controller Rx.

Yagis are used for Transmitters. Ie TV towers. The lengths  have been custom cut to be precise for the TV channel frequency. I think normally 1 wavelength. And a number of them to handle the power output from the RF amplifiers.

1. Where did you get the idea that Yagis are "sub-optimal" receivers?
2. The Yagi kit I ordered (still in transit) comes with two 5.8GHz antennas (which is what I need as the FCC version of the MM only uses 5.8GHz), but I think there are kits with one 2.4 and one 5.8 antenna, for those with CE models. In any case, you can manually set the CE version of the MM to operate on 5.8Ghz, and use two identical Yagis.
3. Yagis are not magic, they won't double your range, but the same goes for parabolic reflectors, they are not any better. Actually (and the reason why I bought the Yagis) there are some good videos around of people testing both, and Yagis seem to have an edge.
4. What do you mean by "I would be cautious testing your Yagi array"?
2020-6-4
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raven swe
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wasn't thinking straight
2020-6-4
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ABeardedItalian
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Jeez what happened here, okay let's see if we can't break this down.

@GeeBax
"Anyone who is into amateur radio and/or building their own antennas will tell you those yagis are never going to produce miracle results, as antenna design is extremely precise, and the higher the frequency, the more precise they become. And you are adding them to an antenna on the RC that is probably designed to work very well on its own, not have spurious lumps of aluminum hung off it."

Thank you for your feedback, while I'm aware these aren't going to produce miracles I was curious what if any real world effect they would have. I have a set of para-bolic boosters that came with my drone, I think the only practical thing they're useful for is to keep the antenna's aligned. I've seen some videos that suggest the Yagi's Do something, is it the 1000+ meters the videos often portray? No, but does it do anything? Yes it actually does, but does it have it's own set of downfalls I'll be bringing up in my later video.

@bjr981s
"Total waste of time. The controller end TX of the RF Link is not the issue. It's the back channel in the drone. Drone Tx to Controller Rx.

Yagis are used for Transmitters. Ie TV towers. The lengths  have been custom cut to be precise for the TV channel frequency. I think normally 1 wavelength. And a number of them to handle the power output from the RF amplifiers.

They are "sub optimal" receivers.

There is available the dual convex range extenders. They do work. Not because they boost the TX signal but the convex shape acts as a lens to focus the RX signal back from the drone. They are also wavelength independent so fine for 2.4 and 5.8 ghz. Think of what a radar dish or satellite dish looks like.

Anyhow I would be cautious testing your Yagi array.

Cheers
"

I would like to know how testing these "Boosters" are going to effect my flight negatively? If the remote loses connection It's set to RTH, losing connection could be considered a negative in the correct context. I've experienced signal drop out on initial installation, not every time but sometimes. There's a procedure for these to be used and I was definitely not displaying it in my video but which I'll correct in future tests. There has been discussion on this forum in this section that I posted in talking about Yagi's and various videos and "Tests" to show they work but a lot of things de-validate those videos. A lot of people raise height which defeats the purpose of having the booster in the first place, the second a lot of people don't re-test in the same location/path that I have done in my video. I'm not expecting miracles as I said above but I wanted to demonstrate if any difference they make in this form and you can see it for yourself I had a little bit of an improvement. Is it life changing? No, in fact It makes things worse unless all you plan to do is fly away from yourself. I'll be covering this in the follow up video but It's about taking what you read and actually seeing the results for yourself, or in my case myself.

@Balooo
"Thank you.. you're the first one to test it on the same track and altitude (from what I've found).. great"

Thank you, I was trying to do a formal demonstration unlike a lot of the videos that are going around. I have more things to show in a follow up video because they aren't perfect and I prefer to fly without them at the moment but I still have some testing to finish.

These are the threads that I was referencing Yagi-Uda antenna range boosters on Ax @m80116 Oscilloscope assessment of various Signal Boosters @PhasedSpaces

I don't know why people are so quick to say I'm wasting my time or that this stupid because X reason. If in your Opinion this is a waste of time then why post? I already made the video so telling me it's a waste of time defeats the purpose no? If you seen a video on something and thought huh, I wonder if that actually works. You see a video using an oscilloscope like the above thread and you can really measure the changes in frequency if any they make. I'm allowed to question what I'm being presented with in this video, I still have doubts knowing they're trying to sell something and to me these "Results" are numbers on a whiteboard, basically it means nothing to me unless I can actually see what if any change they make. So I purchased a set with My Own Money, and used My Time to test and see if what I seen in that video was representative of "Real Life" circumstances and see if they do anything. I'm happy to see they actually can be useful, are they life changing? No, but does it actually translate into somethings psychical? Yes!

I agree replacing the original antenna is the best way of increasing range but this was a simple fun thing to play around with, something most people who has printers can make easily, I don't understand why it's so complexing that I wanted to see what would happen for the fun of it and share the results with what I thought was a nicer community of pilots.
2020-6-4
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22340179
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raven swe Posted at 6-4 09:13
On a proper yagi antenna system you have a physical connection between the driven element of the antenna and feed line from the transmitter, on these you do not.

I tend to agree. They don't look like they would do much in their design. It's easy to test though. Range test with and without, case closed. Post the results here.

I have the parabolic mirror ones and they work. I've lost video feed and throw them on and I get it back and can continue flying out. That said, yesterday I was out some distance and lost video signal and I still had connection and flew towards me with the extenders on pointed in it's direction. Still no video for some seconds. So I took the extenders off and the video came back. So even I have had mixed results with them but overall they seem to work.
2020-6-4
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120ccpm
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raven swe Posted at 6-4 09:13
On a proper yagi antenna system you have a physical connection between the driven element of the antenna and feed line from the transmitter, on these you do not.

Uh? Not really my field, but to my knowledge Yagis have a single driven element, with reflector and directors being parasitic (i.e. not actually connected to the transmitter/receiver). These MM Yagi "boosters" use the original antenna as the driven element, with 1 reflector behind it and 5 directors in front. In other words, while they are certainly not optimized, they are indeed proper Yagis.
2020-6-4
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120ccpm
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ABeardedItalian Posted at 6-4 11:40
Jeez what happened here, okay let's see if we can't break this down.

@GeeBax

[...] I don't understand why it's so complexing that I wanted to see what would happen for the fun of it and share the results with what I thought was a nicer community of pilots.

Completely agree. You did your experiment and shared your findings. I don't remember you saying that everybody should switch to Yagis right away, and those who don't are idiots.
Yet some people - for whatever reason - take these posts that way. And so far I have not seen a single post by someone who actually tried them, and has some direct experience to share.
2020-6-4
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120ccpm
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22340179 Posted at 6-4 13:20
I tend to agree. They don't look like they would do much in their design. It's easy to test though. Range test with and without, case closed. Post the results here.

I have the parabolic mirror ones and they work. I've lost video feed and throw them on and I get it back and can continue flying out. That said, yesterday I was out some distance and lost video signal and I still had connection and flew towards me with the extenders on pointed in it's direction. Still no video for some seconds. So I took the extenders off and the video came back. So even I have had mixed results with them but overall they seem to work.

It's easy to test though. Range test with and without, case closed. Post the results here.

Isn't this what the OP actually did???

As for parabolic reflectors, I agree with you, I tried them on my P3S with very similar results: marginal improvement (although in some situations, still very welcomed), and the occasional odd behavior especially when trying to re-gain signal. All in all, for the price and ease of use, still worth it.
2020-6-4
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Geebax
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120ccpm Posted at 6-4 08:54
1. Where did you get the idea that Yagis are "sub-optimal" receivers?
2. The Yagi kit I ordered (still in transit) comes with two 5.8GHz antennas (which is what I need as the FCC version of the MM only uses 5.8GHz), but I think there are kits with one 2.4 and one 5.8 antenna, for those with CE models. In any case, you can manually set the CE version of the MM to operate on 5.8Ghz, and use two identical Yagis.
3. Yagis are not magic, they won't double your range, but the same goes for parabolic reflectors, they are not any better. Actually (and the reason why I bought the Yagis) there are some good videos around of people testing both, and Yagis seem to have an edge.

'4. What do you mean by "I would be cautious testing your Yagi array"?'

One good example would be if the yagi caused a standing wave conditional in the driven element, reflecting power back into the final amplifier stage.
2020-6-4
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raven swe
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yep there is that possibility to
2020-6-4
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DJI Stephen
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Hello there ABeardedItalian. Thank you for reaching out and for sharing these information and this video with us. Just a reminder, that DJI don't recommend using third-party accessories such as the range extender or Yagi antennas to our DJI Products as we can not guarantee the outcome of using it. Thank you for your understanding.
2020-6-9
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Renato61
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Dji does not guarantee the prompt resolution of the problems, of course that responsibility is discharged, which no one claims, on the use of third party accessories
2020-6-9
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werdschowern
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In germany per law the allowed radiant power is measured up at the antenna and not at the output of the transmitter electronic. Yagi antennas work with a profit. We can argue about the law, but in germany the use of yagi on the mm transmitter is to break the law.
2020-6-9
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Alevpi
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The Russian speaking community has been using the attachment that turns a regular antenna into a wave channel type antenna for about six months!
Yagi has shown its effectiveness for relatively small monetary investments!
There are files for 3D printers to print antennas, two types one for the 2.4 G range the other for the 5.8 g range.
As vibrators, you can use either welding electrodes or a copper core of an electric wire, various materials of vibrators have been tested, the difference in flight range is at the level of error.
2020-6-10
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RampL Aerial photography
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I don’t know about YAGI but if you want maximum range boost on the mavic mini go to Drone-hacks.com
2020-6-10
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Alevpi
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Yagi for 3D printing
2020-6-10
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ABeardedItalian
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RampL Aerial photography Posted at 6-10 01:39
I don’t know about YAGI but if you want maximum range boost on the mavic mini go to Drone-hacks.com

I took a look at that site and I don't see anything of gain, I've already made a thread on how to modify your mini here: Increase Pitch What flight controller is available to be flashed, what does it allow over DJI's stock one?

The lack of information and the fact you can do this without paying for software is a bit ambiguous to me, I understand not everyone is tech savy and with DJI's own assistant tool being outdated, but what else is being done here? I checked the FAQ and no mention of "Custom Flight Controller" was listed.

Also, if you look at mavic pilots you will see that in FW 1.05 DJI has removed the ability to MODIFY Parameters so I assume that's why 1.04 is set to recommended because you can't modify it any longer in 1.05.
2020-6-10
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RampL Aerial photography
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ABeardedItalian Posted at 6-10 09:24
I took a look at that site and I don't see anything of gain, I've already made a thread on how to modify your mini here: Increase Pitch What flight controller is available to be flashed, what does it allow over DJI's stock one?

The lack of information and the fact you can do this without paying for software is a bit ambiguous to me, I understand not everyone is tech savy and with DJI's own assistant tool being outdated, but what else is being done here? I checked the FAQ and no mention of "Custom Flight Controller" was listed.

The big thing is the range boost..
2020-6-10
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m80116
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Can I open a little insight into the origin of the name ?

According to available information it was Shintaro Uda of Tohoku Imperial University that invented this kind of antenna in 1926 with a lesser role played by his colleague Hidetsugu Yagi. Read more on https://en.wikipedia.org/wiki/Yagi–Uda_antenna

Because of this historical fact I think we should never omit the name Uda which is the chief father inventor of the Yagi/Uda antenna.

2020-6-10
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Daniella3d
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Canada
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so which one is the best yagi to get for the mavic mini 5.8g range?
2020-6-10
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m80116
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I opened a thread here https://forum.dji.com/forum.php?mod=viewthread&tid=214412
2020-6-10
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RJn
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For my part, having both, I first use the antenna reflectors and I go over 1500m without loss of signal. I have not tried the yagi in extreme conditions.
Remember that even a small tree branch between remote control and drone can cut the signal. Indeed, we can consider that 5.8GHz is like light.
2020-6-11
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Montfrooij
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Netherlands
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No need for my usage.
Thanks for sharing.
2020-6-23
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Montfrooij
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Flight distance : 2164990 ft
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USS ENTERPRISE Posted at 6-4 06:26
drone       https://youtu.be/j16DQ6iZk_c                 FCC

Are you really posting this video on so many threads?
2020-6-23
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