Mavic pro battery & antenna mod!!!!!!!!!!!!!!!

[CyberNate]

I'm getting this antenna as well! Thank you for testing it!

By the way, when you reached 5 miles out, what happened? The mavic should have a hard limit of 4.97 miles according to the parameter file I found.

In the PARM file the following limits among others can be found:

...
PARM file:
...
<68.918525>(2-9)write go_home_height(40.000000) by hash sender:0x02
<80.538451>(2-10)[write_cfg_item_value_by_hash]-var_addr-"g_config.flying_limit.12"
<80.538574>(2-11)write fly_limit_height(500.000000) by hash sender:0x02
<99.018366>(2-12)[write_cfg_item_value_by_hash]-var_addr-"g_config.flying_limit.10"
<99.018448>(2-13)write fly_limit_distance(8000.000000) by hash sender:0x02
...

Here you see the fly_limit_distance is 8000 meters, which is 4.97 miles.

 

[CactusJackSlade]

5-7 mins longer time,....install is not pleasant...

Kevin

Adding 35% (approx 250 grams) to the weight of my Mavic for 5-7 min longer, plus the hassle of charging up additional battery's with a different charger, now finding a place for said batteries etc... this would not be for me, however the antenna mod is always interesting, not for the distance but potentially better penetration when low to the ground or behind shrubbery/trees etc as well as generally improving the reliability of the signal is always worth considering.

 

[larkin]

I'm sold on the effectiveness of the antenna mod but unsure if it's worth the reduction in convenience of the slick stock setup.

p. s. How bouts a GPS mod [emoji3]

Sent from my XT1650 using MavicPilots mobile app

 

[CyberNate]

I guess by the same token then that you also don't see why television companies, microwave oven companies, car companies, bicycle companies, etc., etc., all list the basic technical information about their products.

If these "Range Extenders" really do what they are claimed to do, any company should be proud to show off their performance by displaying their radiation pattern graphs and other technical info. And, yes, even "non technical" customers can easily compare something like radiation pattern graphs by antennas of different manufacturers at least as easily as they can compare, say, audio amplifier specs such as total harmonic distortion.

Finally, SWR meters only give information about the total impedance mismatch between an RF circuit, or more precisely the transmission line, and an antenna. They don't give any information about the directionality or radiation pattern of the antenna, which is what this discussion is all about.

Real world results and corresponding high recommendations passed on are more valuable than any white papers with radiation patterns to 99.5% of consumers. People care about the final result. When enough people observe the same excellent results, it warrants merit.

 

[Robbyg]

Finally, SWR meters only give information about the total impedance mismatch between an RF circuit, or more precisely the transmission line, and an antenna. They don't give any information about the directionality or radiation pattern of the antenna, which is what this discussion is all about.

Hey, guys. Like I said here before it's your money. If you want to turn over your hard-earned cash for these "Range Extenders" which are accompanied by no technical information at all and show no evidence that they were designed by anyone who knows a thing about RF circuits or antennas, then that's fine with me. If you say that you think you get better range with these things, fine. I'll keep quiet. But if you start pushing some pseudo-scientific BS claims like saying that SWR meter readings show that these "Range Extenders" work then I'm going to call you out.

I am also a ham radio operator. It is interesting that the myth of low SWR is still being used as a measure of antenna performance. I would expect that every ham operator knows that a dummy load produces 1:1 SWR but radiates almost none of the signal. Every antenna sold should have gain figures and radiation patterns for the consumer to analyze and decide if the change in beam pattern is suited for their needs and if the optimum gain figures vs the stock antenna is worth the upgrade.

 

[AlanTheBeast]

That is exactly the case I'm talking about. You are flying under something and RTH occurs. You don't have to far away for this to happen. There is also the case where sun blocks the obstacle avoidance and then the craft hovers until the batteries die. In general having control is better than not having control.

Always better to have control to be sure. But also nice to have RTH even with its limitations.

I hadn't really thought about RTH into the sun with an obstacle stop and disabled RC.

Need to add that to the checklist: if I fly out far, make sure the sun will be placed so it's not likely to cause an obstacle stop if I don't have RC control over the drone.

Add to that: have a bug out location where RC control can be recovered so one can get the drone onto the ground.

The above is not easy!

 

[AlanTheBeast]

Thanks for the basic lesson on linear versus circular polarization, jk. Yes, using a circularly polarized antenna transmitter (or receiver) may make sense of communication with an RC fixed-wing aircraft since those can do barrel-rolls, split-S maneuvers, and all sorts of other maneuvers so that the relative angular orientation of the aircraft with respect to the transmitter can vary all over the place. However, that argument doesn't really apply to controlling a Mavic or other quadcopter, does it?

Still waiting for you to provide some technical info for some of these "Range Extender" antennas. BTW, don't you find it curious and interesting that these "Range Extender" antennas come is so many very different designs even though they're supposed to be optimized for the same frequency?

Most of these range extenders share one simple characteristic regardless of their configuration: they are larger than the stock antenna which is simple and cheap gain.

Further, depending on their configuration, some are directional. Energy is not wasted in directions where the drone isn't but concentrated in the direction where the drone actually is.

Different configurations is not a bugaboo. It just reflects the designers preferred implementation. Each will have its advantages and disadvantages (performance, cost, reliability, ease of use, installation and so on).

In the end, people are getting extended ranges and better signal at long range than with the stock antennas. That's really all that counts. The trick is to make sure one gets the product that actually does work.

 

[AlanTheBeast]

I am also a ham radio operator. It is interesting that the myth of low SWR is still being used as a measure of antenna performance. I would expect that every ham operator knows that a dummy load produces 1:1 SWR but radiates almost none of the signal. Every antenna sold should have gain figures and radiation patterns for the consumer to analyze and decide if the change in beam pattern is suited for their needs and if the optimum gain figures vs the stock antenna is worth the upgrade.

Agree - I suspect the range extender makers don't like giving away too much technical information due to competitive reasons. I also believe this to be against their best interests, not just the consumers.

 

[Wombat55]

Most of these range extenders share one simple characteristic regardless of their configuration: they are larger than the stock antenna which is simple and cheap gain.

But even the simple "intuitive" feeling that "a larger antenna must be better" isn't necessarily true. Look up some basic information on the design of simple antennas. The length of a simple monopole or dipole antenna really isn't a matter of random or personal choice. Bigger isn't better. A simple monopole antenna should be 1/4 of the wavelength of the RF signal in length for maximum efficiency. A dipole antenna should be 1/2 of the wavelength long for maximum efficiency. (Look at and measure the Mavic controller's antennas and note the RF operating frequency and wavelength. You'll probably see that the length of the antennas was not haphazardly chosen.) Now you see how some rube coming up with this own "Range Extender" antenna can go off the tracks. He looks at the stubby little 1/4 wavelength monopole antennas and says "Har! Har! Look at those little tiny midget antennas! I bet I can make them a LOT BETTER by turning them into BIG antennas! Har! Har!". Of course, once the monopole antennas start being extended past 1/4 wavelength, they are no longer at their optimum length and performance is actually degraded. Such are the hazards of practicing medicine without a degree.

 

[Rnl]

People like crying is what is happening to drones

Sent from my VS986 using MavicPilots mobile app

 

[Wombat55]

Agree - I suspect the range extender makers don't like giving away too much technical information due to competitive reasons. I also believe this to be against their best interests, not just the consumers.

It's really not giving anything away to state the performance characteristics of their "Range Extenders" such as giving a radiation pattern plot, is it? Here's an alternative explanation for why they don't give out the performance characteristics: The Range Extenders don't actually work as well as people would like to think and these companies don't want to reveal that or open themselves up to possible legal action by putting out fake radiation pattern plots. Best to remain silent. If someone eventually shows through rigorous testing that the "Range Extenders" don't work, the companies are clean. They can simply shrug their shoulders and say that they never made any claims at all about the performance of the products.

 

[Mark6]

But even the simple "intuitive" feeling that "a larger antenna must be better" isn't necessarily true. Look up some basic information on the design of simple antennas. The length of a simple monopole or dipole antenna really isn't a matter of random or personal choice. Bigger isn't better. A simple monopole antenna should be 1/4 of the wavelength of the RF signal in length for maximum efficiency. A dipole antenna should be 1/2 of the wavelength long for maximum efficiency. (Look at and measure the Mavic controller's antennas and note the RF operating frequency and wavelength. You'll probably see that the length of the antennas was not haphazardly chosen.) Now you see how some rube coming up with this own "Range Extender" antenna can go off the tracks. He looks at the stubby little 1/4 wavelength monopole antennas and says "Har! Har! Look at those little tiny midget antennas! I bet I can make them a LOT BETTER by turning them into BIG antennas! Har! Har!". Of course, once the monopole antennas start being extended past 1/4 wavelength, they are no longer at their optimum length and performance is actually degraded. Such are the hazards of practicing medicine without a degree.

Just reading through this thread and can't help but get annoyed by Womble55's insistence on seeing some peer reviewed proven scientific paper to back up that these aerials work. THERE ISN'T ANY!!

BUT what it seems is that there are people who have tried this MOD and that it does work. How does it work? Who knows how they came up with this particular type of aerial? Maybe by trial and error? Maybe by experimentation on different sized aerials?(Though without the equipment to "measure" the scientific results)

All I can say is that by the amount of people saying that THEY have seen a difference in performance by real life use then that seems like unproven proof to me that they work.

Listening to Womble55 with his "Alternative explanation" for why they don't give out the performance characteristics blah blah blah.

All I can say is to "Womble55".... Where is your Scientific proof on your "alternative explanation"? And I quote from you "that the range extenders don't actually work as well as people would like to think"? Oh wait a second...you don't have any. So you are now trying to disprove that these aerials work without any proof whatsoever. Yet many people on here seem to have proof that they do work. This is from real life "experimentation" of trying a standard aerial against one of these modified aerials.

That's all from me. I'll just carry on waiting for Womble55 to comment again to see if he can post something worthy of his PHD.

I'm out.

 

[Wombat55]

Yeah, there are a lot of people who claim that these "Radar Extenders" work. There are also a lot of people who claim that numerology, astrology, and homeopathy work, too. People have believed in lots of things throughout history, many of which we recognize today as being hilariously wrong ( Methods of divination - Wikipedia ).

Some scientists are not totally immune to wishful thinking, either. I remember that during the Pons and Fleischmann big "Cold Fusion" discovery days that many experimentalists were reporting that they had repeated the "Cold Fusion" tests of Pons and Fleischmann and to their amazement they were finding cold fusion! Of course, later, more careful testing found that that was not true. Many people were simply carried away by their desire to see evidence of cold fusion and it was affecting their judgement.

In the case of Mavic "Range Extender" antennas, some people on these forums have really gotten carried away. One person was even claiming an 8-fold increase in range from his friend's 1/2 mile range to his own "Range Extender" limit of 4 miles in a noisy environment. What makes a claim like that a bit unbelievable is that the intensity of electromagnetic radiation (including RF waves) drops off as the square of the distance from the source. So essentially the person was claiming that his "Range Extender" antenna was concentrating not 8, but 64-times more RF intensity in the forward direction than a standard Mavic controller. Pretty unbelievable.

I'm sure that it is physically possible to come up with an antenna system that concentrates more RF energy in the forward direction and that DJI chose to design the Mavic controller's antennas the way it did as a compromise between antenna efficiency and compactness/portability. I think that we can all agree that DJI must have some pretty good engineers in order to design something as good as the Mavic, and if DJI itself someday comes up with a "Range Extender" antenna of its own, I would be a possible customer. But note this: If DJI ever does come up with and sells its own Range Extender antenna you can be sure of one thing: Unlike the current "Range Extender" companies, if DJI ever sells its own Range Extender they will provide complete performance specs.

 

[dsd317]

Here are my thoughts on this situation.....





....Now, I hope I didn't offend anyone here.

 

[Robbyg]

As someone who has been studying and building antennas for 30+ years, with many of those being made for HF, VHF, C & Ka bands I am not going to say that these Mavic antennas do not work, I think the preponderance of videos and user reports do support the fact that they do indeed work.

The problem I have is how well do they work and in what orientation do they work and it which orientations do they fail. Because folks there is no free lunch with Antennas. If it works really well in one direction it also works really bad in several other directions. For this kind of antenna beam width is key, if it is too narrow then you face the possibility that at extreme distances you may be flying in 100% signal and then move 10 degrees to the left and have Zero signal.

The question of how well does an antenna work is something that is of huge importance to Amateur Radio operators. You can spend $500,000 on an antenna and find out that it really only delivers a bit more performance than a $5000 Antenna and most of that is due to the flawed logic of the designer.

Case in Point: http://www.kkn.net/dayton2006/K9LTN.pdf

The lack of information on the amount of gain for this drone antenna kit is the real deal breaker for me. It's really so simple to get a spectrum analyzer and run tests like these and create charts and all the information that is needed. I have this stuff at home and use it every time I put up a new antenna. Why would a company that sells this stuff not have this kind of equipment?

I say gain is important because with a 1/2 Watt of power on a good antenna I have talked to people 5000 miles away, but that's mostly due to a property that is unique to HF band. At the much higher 2.4Ghz frequency range of drones like the Mavic you need line of sight but when line of sight is achieved you can go a long way on a tiny amount of signal power. Going an extra 30% can be achieved by just several milliwatts of additional power or a slight orientation changes in the antenna. Without a charts to compare the stock antenna versus the upgraded antenna system I have no idea if the amount of work and money needed is justified. I have seen many YouTube videos of guys going out to the extreme edges of the Mavics range with stock antennas. Given that line of sight is maintained the limiting factor seems to be the batteries and not the antenna system.
Now some will point to penetration but to make that leap one needs data because it's not as simple to compare as line of sight. You can pass one concrete building and loose the signal then put on upgraded antennas and go in the same direction but not be blocked because the concrete building was not exactly in the line of sight like before, so now you assume the new antenna is working great. As I said I have seen guys go out so far with stock Mavics that they returned on less than 10% battery power during a controlled RTH that they could not override. If you can do that and yet have no interest in mounting external batteries the whole point of this seems to be academic in nature.

 

[lacion]

@Robbyg, @Shannon-

OK, guys, I respect your views. Sounds like you're at least going in with eyes wide open. As for me, I'll hold back on getting any antenna "Range Extender" until I see actual technical specs, preferably from a company I already know and respect like DJI itself.

You make a good point that there's no free lunch and that in order to direct more RF power forward an antenna would have to effectively "steal" radiated power from other directions. So a simple first test to try would be to see how far the drone could be flown if one turns one's back on the drone as it flies away in order to test how much radiated power is going in a backwards direction. If these "Range Extenders" really work as intended, then contact with the drone should be quickly lost at a relatively short distance if one is oriented at any other direction than directly facing the drone. It's interesting that with all of the claims about the superb performance of these "Range Extenders", I haven't even seen even a single report of anyone doing this very simple, basic test.

i had to respond to this because simply your use of "range extenders" is hilarious. the pcb antennas on the mavic remote are very crappy (even for a company you know and respect like DJI) their cheap antennas, by simple using other antenna geometries and make the beam more directional you not only gain range but you also gain penetration and fight ghosting.

is a site like Max my range which is aimed to RC hobbiest you can select different antennas geometries with different frequencies and see a (best condition situation range.)

when i changed the pcb antenna on my Inspire 1 to the Patch antenna kit it was day and night. penetration improved so much i could fly behind lots of trees with 0 problems on image. the catch is that you need to point your antenna to your AC or you will loose signal.

 

[Wombat55]

i had to respond to this because simply your use of "range extenders" is hilarious. the pcb antennas on the mavic remote are very crappy (even for a company you know and respect like DJI) their cheap antennas, by simple using other antenna geometries and make the beam more directional you not only gain range but you also gain penetration and fight ghosting.

is a site like Max my range which is aimed to RC hobbiest you can select different antennas geometries with different frequencies and see a (best condition situation range.)

when i changed the pcb antenna on my Inspire 1 to the Patch antenna kit it was day and night. penetration improved so much i could fly behind lots of trees with 0 problems on image. the catch is that you need to point your antenna to your AC or you will loose signal.

Well, if you think that your Range Extender antenna really works, then why don't you try seeing how far out you can control your drone when your controller is oriented at various angles with respect to the drone so as to generate at least a crude radiation pattern plot for your Range Extender antenna? I'm sure a lot of people would be very curious to see it. In truth, as I've been saying all along here, that's basic information that the antenna company itself should have provided to everyone, but maybe at least the user community can start providing some radiation pattern information rather than everyone simply reporting their claims of how far they could fly.

 

[lacion]

Well, if you think that your Range Extender antenna really works, then why don't you try seeing how far out you can control your drone when your controller is oriented at various angles with respect to the drone so as to generate at least a crude radiation pattern plot for your Range Extender antenna? I'm sure a lot of people would be very curious to see it. In truth, as I've been saying all along here, that's basic information that the antenna company itself should have provided to everyone, but maybe at least the user community can start providing some radiation pattern information rather than everyone simply reporting their claims of how far they could fly.

no one here is making new antenna geometries, there is plenty of of information on the internet about how different patterns radiate RF.

you can make antennas at home that will be as close as 95-99% close to anything produced in a lap by just following the right geometry.

theres people with RC planes doing 10km with antennas made at home by them, there 3 os such people in my rc fly club. i used to make my own circular polarized antennas using a simple 3d printed gig, that is still working on my 250 racer.

 

[AlanTheBeast]

Very well said,.....but Mr. PHD still won't get it!!

But even the simple "intuitive" feeling that "a larger antenna must be better" isn't necessarily true. Look up some basic information on the design of simple antennas. The length of a simple monopole or dipole antenna really isn't a matter of random or personal choice. Bigger isn't better. A simple monopole antenna should be 1/4 of the wavelength of the RF signal in length for maximum efficiency. A dipole antenna should be 1/2 of the wavelength long for maximum efficiency. (Look at and measure the Mavic controller's antennas and note the RF operating frequency and wavelength. You'll probably see that the length of the antennas was not haphazardly chosen.) Now you see how some rube coming up with this own "Range Extender" antenna can go off the tracks. He looks at the stubby little 1/4 wavelength monopole antennas and says "Har! Har! Look at those little tiny midget antennas! I bet I can make them a LOT BETTER by turning them into BIG antennas! Har! Har!". Of course, once the monopole antennas start being extended past 1/4 wavelength, they are no longer at their optimum length and performance is actually degraded. Such are the hazards of practicing medicine without a degree.

I won't argue that at all. OTOH, size isn't just length. Area (multiple elements) = more gain and directionality. The fly in this ointment is that the dipoles would have to be stacked vertically - to effect gain and directionality - not what I've seen in these antennas.

One of the antennas offered looks a lot like it contains two flat panels ...

One has this "jungle gym" configurations that I don't get at all...

 

[F6Rider]

I've said it before: If all these Range Extender antennas are legit, how come none of the companies give and technical engineering specs or radiation patttern graphs or give any indication that the people who designed them have any background in RF engineering or RF antenna design?

BTW, this week only I'm having a Special Sale! My unique, customized Range Extender Tinfoil Hats! 50% off! Hurry while they last! Check out the other great deals, too, at "Honest Wommie's" website!

I too would like to see the spec's and RF radiation pattern, but on the other hand as a long time HAM I know that the 'Yagi' antenna design has been around for a long time and has proven performance, I have used them for many rigs from 2-20 meters FM & UHF/VHF radios.