That's not my picture first off, second, I have just one single battery clip
on mine, and my two thunder power prolite 910 batteries have jst plugs
on them. custom made to fit into the one 60 plug, then plugs into the
battery clip.....
Mavic pro battery & antenna mod!!!!!!!!!!!!!!!
- Thread starter jkantiques
- Start date
That's not my picture first off, second, I have just one single battery clip
on mine, and my two thunder power prolite 910 batteries have jst plugs
on them. custom made to fit into the one 60 plug, then plugs into the
battery clip.....
beanbubba
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Thanks jkantiques. Any particular reason you didn't custom make your cables to use one port on adapter for each battery?
Because he had the older version of the battery mod which has a single xt60 connector.
Wait, we have a winner. This has to be the single biggest pri_k comment I've ever seen on this forum. What a sad existence to get this worked up over another person's toy drone hobby. Wow. I love running into these types at parties...
GooniesNeverDie
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Yeah no [emoji90]!
This guy is the guy ruining the drone industry by thinking he is somehow the authority or world police.
As of now, call the FAA. The FAA registration and their "guidelines" or suggestions are null and void now for hobbies, which most people are.
This is #Merica and we eat regulations and poop Screaming Bald Eagles baby! Yee haw!
By the way 5 miles? lol. We can go further!
beanbubba
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I am new to the drone hobby and completely enthralled. I have spent half of my career working on commercial radio and antenna systems and this thread has been the most entertaining thing I have seen in a while. In my company, we have non-radio folks spout off about RF theory for years and it is almost identical to this thread. I can say from first blush that this antenna mod has legs and I have one on order. I plan to do some scientific analysis and will report back when complete. I am pleased to see all the different personalities on all sides of this debate and look forward to more interactions.
I think that directional antennas are better than omni directional antennas given you are targetting one RX/TX, you just have to remember to point the controls in the direction of flight. They work great with my FPV racing drones and my amateur radio so I'm up for switching the antennas out on my Mavic remote. I'm not looking for long distance, but less signal dropout.
After looking at looking at these antennas, they appear to have some thought gone into them and appear to be directional antenna types. I can't confirm their effectiveness though without testing. As you are not trying to target multiple locations these should operate better than a whip antenna. Its like using a spot light over a floodlight when you can pinpoint what you are looking for.
After looking at looking at these antennas, they appear to have some thought gone into them and appear to be directional antenna types. I can't confirm their effectiveness though without testing. As you are not trying to target multiple locations these should operate better than a whip antenna. Its like using a spot light over a floodlight when you can pinpoint what you are looking for.
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beanbubba
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Aczi,
Yes, I just finished my battery and antenna mod's and can positively state these antenna mod's are the real deal. I just got all this setup and my next tests are to survey the antennas you can buy referenced in this thread and compare them to well known commercial antennas like I have installed. Within a reasonable margin, I will be able to state the specifications of these antennas that don't publish their dBi gain or antenna pattern.
I used spare parts from work with a 2.4gHz 30x30 degree panel antenna with link budget and plots attached. I also added the geometric 3D coverage pattern on google earth for reference (-85dBm in this example of my current setup). You can see I also built this that allows me to fly from inside my workshop. It's pretty fun stuff!
The details can be found in these other threads:
"Official Mavic Range Leaderboard" Page 33.
Official Mavic Range Leaderboard
"Official Mavic Range Leaderboard" Page 34.
Official Mavic Range Leaderboard
"Mavic Pro Battery Mod" Page 34.
Mavic Pro Battery Mod
@beanbubba
I have strong electronical skills and some ideas about antennas, but not a full technical background with them.
I am wondering what happens or if it makes sense, if one of the antennas can be rotated by 90 dec, this should have some impact on coverage but is it bad or good and in which scenario this makes sense?
beanbubba
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I am still preparing the testbeds for upcoming analysis. But I had to run a quick test that is not scientific, but rather a quick litmus check on antenna types that @aczi asked about until I can produce detailed reports.
I am currently using a dual element (two N type antenna connectors) 2.4 gHz 30x30 degree panel antenna. One element is vertically polarized and the second is horizontally polarized. There is little documentation I can find on the mavic remote and aircraft wireless systems, but we can infer and make educated guesses on behavior that closely mimics open commercial systems.
I would suspect that the remote and aircraft have vertically polarized antennas and you will see below some evidence to support this. You might ask why does your antenna have differing polarization for each element? Well, in commercial Wi-Fi and other related systems, things like diversity and multiple input technologies can benefit from the differences of the two signals and make calculations to digitally improve data throughput.
I setup a simple test course to run identical paths and identical hardware. The mavic remote has two antenna elements. With the remote in your hands in normal flying position, I will refer to the left and right radio antenna connectors.
Based on scope analysis in prior testing, the left radio connector is configured to TX/RX (transmit and receive). The right radio connector is RX only. I can infer that the mavic employs some kind of technology to improve the overall RX performance by using the remote right port for improved data throughput of the RX video stream.
Here are the 4 test runs that I performed 5 times each. I ran the mavic in a straight line on the same path until all signal was lost and RTH kicked in.
Left Remote port to Horizontal Polarized Antenna
Right Remote port left unplugged
Left Remote port to Horizontal Polarized Antenna
Right Remote port to Vertical Polarized Antenna
Left Remote port to Vertical Polarized Antenna
Right Remote port left unplugged
Left Remote port to Vertical Polarized Antenna
Right Remote port to Horizontal Polarized Antenna
Right Remote port left unplugged
Left Remote port to Horizontal Polarized Antenna
Right Remote port to Vertical Polarized Antenna
Left Remote port to Vertical Polarized Antenna
Right Remote port left unplugged
Left Remote port to Vertical Polarized Antenna
Right Remote port to Horizontal Polarized Antenna
:::
TEST-1
Left Remote port to Horizontal Polarized Antenna
Right Remote port left unplugged
:::
TEST-2
Left Remote port to Horizontal Polarized Antenna
Right Remote port to Vertical Polarized Antenna
:::
TEST-3
Left Remote port to Vertical Polarized Antenna
Right Remote port left unplugged
:::
TEST-4
Left Remote port to Vertical Polarized Antenna
Right Remote port to Horizontal Polarized Antenna
:::
This data sample is too small to make any serious conclusion, but there is evidence to suggest that using vertically polarized antennas on the left connector produces the best results. Time will tell and I will perform more tests and report back to the group at a later date, but wanted to give @aczi a response to his question from this morning.
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Why are the distances so short before the signal is lost? Is that because you are flying low and in an area with obstruction between you and the drone? I believe the antennas are vertically polarized as the dipole antenna are on the front legs of the Mavic.
Strangely I get the best performance with Circular Polarized antenna. Yes, it doesn't make sense as you would expect 3dB loss between CP and LP, but I get way better results with my CP as compared to my linear polarized ones, and I have both Nanosync and the FPVLR yagi type. I am no antenna expert, but I tried different combinations and found this RexUAV CP type works well boosted. I assume it is the isolation of the left and right (which I assumes are TX and RX) due to the opposite polarization on each side. The linear antenna result in a lot of interference indicated by the blinking RC and HD icons on the controller and poor video quality I see at that time.
With CP type I get rock solid video and less interference overall. I am interested to hear the finding of an expert like you to see where improvements can be made. I run Sunhams 3W amps on both left and right sides of the controller.
beanbubba
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I purposely setup a short course with antenna pointed away at 45 degrees so it would lose signal quickly (and this allowed 20 tests in a reasonable amount of time). Can you do me a favor and fly a course you are very familiar with the numbers, and unplug the right antenna port for the entire flight and report back any differences you see in the flight characteristics?
I've done that test several times. I usually lose my connection, as the right antenna is the weak link once left side is boosted. I can test it again when I get back to states in a couple days.
beanbubba
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I apologize again for being late to the game, I don't know what all you guys have and have not tried. I will keep the spam down to a minimum until I have something interesting to share.
sprtbkrydr
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I'm not sure I can see how this guy made it out 5 miles and back with just a clip mod a nd a set of 900mAh batteries. What am I missing here?
beanbubba
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I asked the same questions over the last few weeks. Cybernate went into great detail on the methods used. Read all his posts from the last month. But no matter what, near zero wind seems to be the common denominator on record setting runs.
Sorry, I didn't mean it in a dismissive way. I appreciate all of your testing and ideas. I'm sure there is a lot we can improve. I don't mind to run the test again when I get back. I've tried disconnecting right side antenna, as well as by passing the amplifier to compare amped to non-amped on right side. The amps help only slightly on the right side as that is RX only. I didn't realize that the left side also has RX in addition to TX. It's possible as there are 2 RX streams. We have the video feed as well as telemetry data.
beanbubba
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FYI - I was able to surmise that the RX feeds to the remote are shared across both the left and right remotes ports. There is no specific function tied directly to either port and the aircraft will fully function with only one of the two RX ports. But the RX signal quality will incrementally improve when there are antennas on both ports. I have not proven this yet, but I suspect that differing the antenna polarizations across the two ports will improve RX signal quality even more.
Also, these consumer amplifiers don't publish detailed specifications. From experience, I have worked with other brands of amplifiers rated at 3 watts (or ~35 dBm) for TX. What they don't tell you is that these amp's can only "boost" the RX stream by ~16 dBm. They only publish the TX spec's. This is a well known behavior in the industry for these type of devices.
Lastly, everyone on this forum is worried about the FAA, but we should also be worried about the FCC because these mods are waaaaay outside the allowed EIRP, but I won't tell if you don't
Also, these consumer amplifiers don't publish detailed specifications. From experience, I have worked with other brands of amplifiers rated at 3 watts (or ~35 dBm) for TX. What they don't tell you is that these amp's can only "boost" the RX stream by ~16 dBm. They only publish the TX spec's. This is a well known behavior in the industry for these type of devices.
Lastly, everyone on this forum is worried about the FAA, but we should also be worried about the FCC because these mods are waaaaay outside the allowed EIRP, but I won't tell if you don't
FYI - I was able to surmise that the RX feeds to the remote are shared across both the left and right remotes ports. There is no specific function tied directly to either port and the aircraft will fully function with only one of the two RX ports. But the RX signal quality will incrementally improve when there are antennas on both ports. I have not proven this yet, but I suspect that differing the antenna polarizations across the two ports will improve RX signal quality even more.
Also, these consumer amplifiers don't publish detailed specifications. From experience, I have worked with other brands of amplifiers rated at 3 watts (or ~35 dBm) for TX. What they don't tell you is that these amp's can only "boost" the RX stream by ~16 dBm. They only publish the TX spec's. This is a well known behavior in the industry for these type of devices.
Lastly, everyone on this forum is worried about the FAA, but we should also be worried about the FCC because these mods are waaaaay outside the allowed EIRP, but I won't tell if you don't
Actually, I wanted to ask you about amplifiers. The Sunhams 3W amp is only putting out 170mW. Do we need preamps to get the full 3W? It's basically 4 times the power of the controller, giving more than double the range when coupled with higher gain antenna, but still a tiny fraction of advertised power. I wonder if one could put the Sunhams amps in series to get full power. The first would act as the preamp. I suppose it might be to strong in preamp role, exceeding input maximum on the the second amp.
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