Mavic Range Extenders

Discussion in 'General Discussions' started by ntpd, Dec 28, 2016.

  1. ntpd

    ntpd Member

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  2. jointeffort

    jointeffort Well-Known Member

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    Just bought those and got them delivered today. Still waiting for Mavic. I used something similar on P3S and had good results.


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  3. ntpd

    ntpd Member

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    Thanks. The physics of it makes sense. Just wanted to make sure it wasn't snake oil.


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  4. msinger

    msinger Well-Known Member
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    They have no reviews yet, but you can also pick up that range booster for $5 here on Amazon.
     
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  5. mikecorn.1

    mikecorn.1 Member

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    I have some for my P3A. They do help out. Don't know if they will be needed with the newer technology on the Mavic. You can only go so far on the stock batteries anyways.
    Still might order some for when I fly out from my house


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  6. frankiez

    frankiez Well-Known Member

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    Just ordered a pair. Maybe I am just being paranoid but anything that can help me maintain a strong signal to my Mavic will give me peace of mind. Especially when they are so inexpensive.
     
  7. Geo

    Geo Active Member

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    Yea I used them on my P3P. I would say about a 30% increase in distance at best. But for $5 they are sure worth a try. The science does work.
     
  8. frankiez

    frankiez Well-Known Member

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    I saw a youtube video of a guy who was testing them out on a Mavic. He did a side by side comparison with and without them. Actually seemed to be worse with them.
     
  9. skypros

    skypros Well-Known Member

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    Allot of this stuff is just more Cr@p that we think (want) to work when in reality it is just more junk that we pay a few bucks for and think that it actually helps...... Then It will just take up room in our storage cases.

    It is just like washing our cars...... and then we think the car "drives/rides" better.....
     
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  10. CAlexio

    CAlexio Member

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    i was in south africa on a yacht offshore, and i flew my mavic to shore and dropped into the world cup stadium in capetown. Once I got into the stadium i was losing signal so I had to fly home. would a range extender have helped in this situation?
     
  11. Davidss

    Davidss Well-Known Member

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    All the items linked to are specified for the Phantoms.
    I'm interested in the Mavic; is the antenna spacing on the Mavic Controller the same as on the Phantom 3 Pro & 4 controllers, or does a single extender, designed to fit both antennas at once, have to be specific to the Mavic?

    Thanks.
     
  12. msinger

    msinger Well-Known Member
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    No. You should only buy products that are designed for the Mavic remote controller.
     
  13. Wombat55

    Wombat55 Well-Known Member

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    I don't know, guys. Look, I don't claim to be an expert in RF antennas but I do have degrees in physics (Ph.D. Cornell, B.A. Berkeley) and have heard a lot of snake oil salesmen over the years who have claimed great (but completely nonsensical and unphysical) performance of "scientifically engineered" gizmos of everything from audio cables to gasoline additives. Here's what bothers me about the Range Extender shown in the link: if I were a huckster and wanted to come up with some fake "range extenders" to separate people from their money, the thing shown in the link is probably pretty close to what I would come up with. Two shiny, mirrored reflectors shaped in a concave shape as IF the task of reflecting RF waves emanating from the antennas were exactly analogous to reflecting light waves emanating from the antennas. Of course, RF waves have much, much longer wavelengths than light waves and engineering RF wave reflectors is much, much different from engineering light reflectors. Take a look at a Yagi antenna and try to use your intuition and familiarity with light wave reflectors to try to figure out how the Yagi antenna works. You almost certainly can't. Your intuition fails.

    Again, I'm not an expert on RF antennas, but my gut feeling from looking at the picture of the Range Extender is that it probably doesn't work and was something that was haphazardly designed by someone who knows nothing about RF engineering.
     
  14. c hardy

    c hardy Active Member

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    You are probably correct. But I've already bought a set. LOL Darn Snake oil...
     
  15. Davidss

    Davidss Well-Known Member

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    Thankyou.
     
  16. Oyibo VFX

    Oyibo VFX Well-Known Member

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    Ordered on AliExpress, waiting to arrive


    Adventure is just bad planning
     
  17. HK!

    HK! Well-Known Member

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    Lol, I was going to say they are so ugly/impractical that they must work. I feel stupid enough wearing VR headset. I dont need gold Solar panels on my sexy controller.

    If there was a device that gelled with, pimped the look of the controller to get extra range, even if it made %5 difference your probably going to buy it.
     
  18. Wombat55

    Wombat55 Well-Known Member

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    Again, just my suspicions. From a physics standpoint the issue is this: The wavelength of visible light is in the range of 0.0001 cm. I believe that the Mavic controller operates at around 2.5 GHz, which corresponds to a wavelength of a bit over 10 cm. Now the "Range Extender" appears to place its reflectors only about a cm or so away from the RF controller's antennas. Since that distance is less than the wavelength of the RF waves, the interaction and coupling of those concave "reflector-like" metal surfaces of the "Range Extender" with the antennas is likely to be quite complicated. It's not at all like the optical reflector in a flashlight, where the distance between the reflector and the light bulb is much, much greater than the wavelength of light. In fact, you may even find that you get better performance with the "Range Extenders" if you install them "backwards" on your controller, with the shiny, concave metal surfaces facing towards you instead of away from you, although I suspect that not using them at all would probably give the best performance.

    But these are just my opinions based on educated guesses. The real proof of the pudding is how these "Range Extenders" actually work in real life tests. Hope that anyone who is using these reports back on these forums with some rigorous test results about how well they perform by comparing the performance both with and without the "Range Extenders" on controller, as well as installing the Range Extender both "correctly" as well as "backwards". Would be interesting to see the results.

    (P.S.: Putting the Range Extenders on backwards may actually be a good first test. If the idea behind them is that they are supposed to "reflect" the "wasted" backwards-travelling RF waves into the forward direction, then you should see a large degradation in the effective range of the Mavic controller if the Range Extenders are put onto the antennas backwards.)
     
    #18 Wombat55, Feb 14, 2017
    Last edited: Feb 14, 2017
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  19. Davidss

    Davidss Well-Known Member

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    If you want to see results of tests, although not all the variations you have thought of, you can do little worse that looking at those done by the chap who (indirectly) is being accused of selling expensive snake oil.
    Drone Valley (I think his name is Rick, but I can't really handle the accent very well).
    His tests are on the Phantom, not the Mavic, but the frequency will be the same.

    If you want 'independent' tests, with apparently nothing to sell, try this Australian actual flight test. Again a Phantom.

    Another Phantom based flying test, defying the 'science'. Although he doesn't show the screen, merely quotes the numbers. What is interesting is that for his final test he flew in a 'poor' signal / range area, and got a much increased range. This tends, in my view, to reinforce what the Drone Valley man asserts, the range extenders don't JUST give you a longer range, but by punching a stronger signal ensure the drone works better in a hostile environment.

    What we need now is some Mavic owners to do similar tests.
    OF COURSE I'd try this on my Mavic, if only DJI would ship me the one I've paid for :)

    Regards.
     
  20. Wombat55

    Wombat55 Well-Known Member

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    OK, first of all I'm going to have to come down a little hard on "Rick" of the Drone Valley video and his "scientifically proven" claim. RF transmission patterns from an antenna have both a "near-field" region and a "far-field" region. The "near-field" region is the region at distances comparable to the wavelength of the RF wave, which is around 12 cm (about 5 inches) for the transmission frequencies of these drones. "Rick", who by his own admission is not a scientist and probably doesn't know the distinction between "near-field" and "far-field" antenna regions, placed his detector nearby the RF controller on the same table in the vicinity of the antenna's near-field region. That not the proper way to do the test, since obviously when we are flying drones the drone is always in the "far-field" region of our controller's antenna.

    Also, despite talking at length about how his Range Extender concentrated the RF signal in the forward direction, Rick didn't do a very simple test: Show us how the signal amplitude at the detector varied as he moved it in a 360-degree circle all around the RF controller. If the Range Extender were really concentrating RF power in the forward direction, then we should see a drop-off in signal as the detector moved to the sides and rear of the controller, and then the signal increase in strength again as the detector moved in front of the RF controller again. (And, again, all these measurements should really be done with the detector much, much further away from the RF controller so that the detector is always in the RF controller's antenna's far-field.).

    As for the Australian flight test, there simply isn't enough information presented to judge the accuracy/truthfulness of the video and whether it was a properly conducted scientific test. That's why we physicists write up long, detailed papers which tediously list and describe all of our experimental conditions and parameters and procedures, and why we don't simply make quick 5-minute YouTube videos in order to establish scientific claims.
     
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