FCC MINI not achieving the 4000 meters distance!
- Thread starter André Denis
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At those distances and at that altitude, the curvature of the earth starts to come into play. Find a tall hill to fly from (250 feet or higher) over open ground below, and you should be able to achieve much greater distance very low to the ground. Adding a small windsurfer will also help.
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If the drone is 200 feet you should be able to have LOS well over 20km with the controller sitting on the ground- what do you see as the earth curvature issue? Some propagation effect other than LOS? I have noticed that over 200ft ALT gives better range once you get to 2km+. This is in the middle of nowhere over flat terrain (dessert),
WithTheBirds,
'200ft ALT gives better range once you get to the 2km+'. I like this sentence! Is this with the Mini?
'200ft ALT gives better range once you get to the 2km+'. I like this sentence! Is this with the Mini?
TDZHDTV
Well-Known Member
Not all DJI drones are made equal, I crashed a Mavic Air once, it was replaced with a new MA, the replacement was a polar opposite to the original regards range and video feed, so much so I was able to demonstrate to the insurance company and obtained a 2nd replacement which had the same range and performance as the original. I can fly my CE 1300 metres before video breaks up, only done it once to test the AC as I believe VLOS is the safest option.
As I mentioned regardless of what DJI says concerning range has nothing to do with the reality of what the aircraft can do and what is safe.
They rated the original phantom four at 4000 km. Good luck with that.
From what you said I would conclude it is performing well within specification.
Flying a Mavic mini beyond 500 m is very risky and obviously well beyond Vlos. so I would rate your attitude concerning risk as “I am willing to except a very high level of risk.”
Just based on what you said.
Which is fine as I said it’s your drone to lose as you see fit. Just know from the experience of others here in this forum it’s definitely high risk.
I always fly from an elevated location, so I can fly at 50° AGL or lower out to over 5.4 miles without any problem, other than the battery life, for anything other than a suicide mission. Everyone else has to fly proportionately higher, the farther away they fly, over level ground. Clearly, something requires increasing altitude with distance. If it isn't the curvature of the earth, then something else is blocking clear LOS. Not everyone, including the OP, necessarily flies over flat terrain in the middle of nowhere.
Followed your advise, GadgetGuy. This desert i'm in is at the base of a chain of small hills. I climbed to about 80 feet, and launched from there. Raised the drone to another 100 feet above, and sent it straight across the desert. I got further away than before: 1600 meters. That is a far cry from your 5.4 miles! Along the way, i receive a few 'warning low signal, st antennas'. When that happens, i stop the forward motion, backup 20 meters. The warning goes away. I then move forward and surprise! No warning when i pass the position where i got the warning. I played this little game until i got to the 1600 m. mark. It was clear i could go no further.
I though maybe the signal beam is very directionnal, and if i'm off by a few degrees, that would trigger the 'low signal warning'. But no, even passed 1200 m, i can rotate horizontally the controler by a few degrees, and no warning. More sensitive if i rotate vertically.
Here is a screen of the transmission tab. It shows the channel selected. I think it shows the power level at -88 dBm. Do you have the same level, when you go that far?
André
I though maybe the signal beam is very directionnal, and if i'm off by a few degrees, that would trigger the 'low signal warning'. But no, even passed 1200 m, i can rotate horizontally the controler by a few degrees, and no warning. More sensitive if i rotate vertically.
Here is a screen of the transmission tab. It shows the channel selected. I think it shows the power level at -88 dBm. Do you have the same level, when you go that far?
André
My statements above should have been clarified as being based upon the M2 rather than the MM, but the exact same principles apply, despite the differences in advertised ranges. If you can get to 250' above the surrounding area below you, you will achieve the optimum clear LOS distance. MM uses a less robust transmission system than the M2's OcuSync 2. If you can locate the source of the interference, and avoid flying over it, or use a different channel, you will be able to go farther. A windsurfer will also add a good 10-15% to your range. Intermittent hills interfere with the signal. If you can fly over water, the signal can reflect easily off the surface for even better range. Fortunately, the flight time of the MM battery allows lots of forgiveness when testing its 4km max range, unlike the M2! Good luck!
LankALank
Well-Known Member
I like to test the mm distance also I’ve been 7700 feet that’s the furthest I ever got it
Saigondroner
Well-Known Member
I've got to say I concur with Done's assessment of your comprehension about RF propagation. IMHO, you are not actually properly "testing" anything, but you are selectively comparing your anecdotal experiences to an select few of DJI's published specifications that support your expectations . For example, you said the your FCC model is behaving as if it were a CE model. Do you have both FC models? If not, upon what basis can you make that claim?
Even if you do have both FC's you've asked how to properly measure the TX power. You need to get yourself a multiband spectrum analyzer and build yourself a Faraday cage large enough to work inside. You need to obtain the right cables and connectors, remove the antennae and measure the EIRP as close as possible to the transmitter chipset. Radio manufacturers commonly publish specifications whose range performance is theoretical, and based on smooth earth computer models, with no consideration of any terrestrial interference, antenna characteristics, nor atmospheric attenuation.
You seem to be hung up on DJI's specifications, specifically the "FCC" bit. Let's have a look!
Transmitter Power (EIRP)
ModelMR1SS5: 5.8 GHz: <30 dBm (FCC); <28 dBm (SRRC)
ModelMR1SD25: 2.4 GHz: <19 dBm (MIC/CE)5.8 GHz: <14 dBm (CE)
Max Transmission Distance (unobstructed, free of interference)
Model MR1SS5: 5.8 GHz: 4000 m (FCC); 2500 m (SRRC)
ModelMR1SD25: 2.4 GHz: 2000 m (MIC/CE) 5.8 GHz: 500 m (CE)
The 1st thing you should know is that all of these specifications are based on different test methods. Your MR1SS5 lists different specs for exact same device. Why have you not mentioned the SRRC measurement of <28dBm? The SRRC Tx distance is estimated at only 2500m.
SRRC is the State Radio Regulation Authority of China, BTW.
Have a read about SRRC
Next, the MR1SD25 (the CE version) is dual band.....2.4 Ghz & 5.8 Ghz, and has a lower Tx power. Did you know that 5.8 Ghz band suffers from a much greater attenuation, due to atmospheric conditions, obstacles, and over the horizon loss? Its signal loss is enormous, when compared to 2.4 Ghz...that, plus the CE test method actually reduce the max Tx distance estimated to 500m (or 1/8 the distance of the FCC test estimate). Using the FCC model, you're stuck with a radio spectrum that is much more loss prone and directional, with no option to switch to 2.4 Ghz. 5.8 Ghz requires more Tx power, in order to be reliable.
As far as Max Tx distance goes, DJI clearly states unobstructed, free of interference. Why on earth would you imagine being able to reach 4000m distance? Unless you live on a giant cueball in the vacuum of outer space, there is no hope to achieve 4000m.
IMHO, you need to study a bit of radio theory, completely and totally reset your expectations about the Mavic Mini, and chill out a little.
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Saigondroner
Well-Known Member
That is just short of the Chinese State Radio Regulation Authorities published max distance spec...consider yourself lucky the MM returned. Flying in near the Blue Ridge?
Saigondroner
Well-Known Member
LankALank
Well-Known Member
Yes I live in the valley of the blue ridge mountains.so I go on the overlooks and let my Mavic Mini go loose into the hills
LankALank
Well-Known Member
You attributed this quote to me in post #33.
I did not post it, and the only thing I agree with is the first sentence.
Please be careful when combining post from multiple posters.
The M2 OcuSync signal is reliable out to well over 5.4 miles with clear LOS.
MM control range is only advertised for 4 km, not the 8 km of the M2.
Last edited:
Saigondroner
Well-Known Member
Apologies....my bad. I use spotters with VHF radios approaching 9.5km clear LOS, as it is well beyond my visual accuity. Yes, the MM is advertised from 500m-4000m, depending on the FC model, assuming smooth earth conditions, unobstructed. M2P is more...
Saigondroner
Well-Known Member
[mắm ruốc
I believe I quoted myself. Please substitute any drone makers' specs as you deem needed.
've got to say I concur with Done's assessment of your comprehension about RF propagation. IMHO, you are not actually properly "testing" anything, but you are selectively comparing your anecdotal experiences to an select few of DJI's published specifications that support your expectations . For example, you said the your FCC model is behaving as if it were a CE model. Do you have both FC models? If not, upon what basis can you make that claim?
Even if you do have both FC's you've asked how to properly measure the TX power. You need to get yourself a multiband spectrum analyzer and build yourself a Faraday cage large enough to work inside. You need to obtain the right cables and connectors, remove the antennae and measure the EIRP as close as possible to the transmitter chipset. Radio manufacturers commonly publish specifications whose range performance is theoretical, and based on smooth earth computer models, with no consideration of any terrestrial interference, antenna characteristics, nor atmospheric attenuation.
You seem to be hung up on DJI's specifications, specifically the "FCC" bit. Let's have a look!
Transmitter Power (EIRP)
ModelMR1SS5: 5.8 GHz: <30 dBm (FCC); <28 dBm (SRRC)
ModelMR1SD25: 2.4 GHz: <19 dBm (MIC/CE)5.8 GHz: <14 dBm (CE)
Max Transmission Distance (unobstructed, free of interference)
Model MR1SS5: 5.8 GHz: 4000 m (FCC); 2500 m (SRRC)
ModelMR1SD25: 2.4 GHz: 2000 m (MIC/CE) 5.8 GHz: 500 m (CE)
The 1st thing you should know is that all of these specifications are based on different test methods. Your MR1SS5 lists different specs for exact same device. Why have you not mentioned the SRRC measurement of <28dBm? The SRRC Tx distance is estimated at only 2500m.
SRRC is the State Radio Regulation Authority of China, BTW.
Have a read about SRRC
Next, the MR1SD25 (the CE version) is dual band.....2.4 Ghz & 5.8 Ghz, and has a lower Tx power. Did you know that 5.8 Ghz band suffers from a much greater attenuation, due to atmospheric conditions, obstacles, and over the horizon loss? Its signal loss is enormous, when compared to 2.4 Ghz...that, plus the CE test method actually reduce the max Tx distance estimated to 500m (or 1/8 the distance of the FCC test estimate). Using the FCC model, you're stuck with a radio spectrum that is much more loss prone and directional, with no option to switch to 2.4 Ghz. 5.8 Ghz requires more Tx power, in order to be reliable.
As far as Max Tx distance goes, DJI clearly states unobstructed, free of interference. Why on earth would you imagine being able to reach 4000m distance? Unless you live on a giant cueball in the vacuum of outer space, there is no hope to achieve 4000m.
IMHO, you need to study a bit of radio theory, completely and totally reset your expectations about the Mavic Mini, and chill out a little.
I believe I quoted myself. Please substitute any drone makers' specs as you deem needed.
've got to say I concur with Done's assessment of your comprehension about RF propagation. IMHO, you are not actually properly "testing" anything, but you are selectively comparing your anecdotal experiences to an select few of DJI's published specifications that support your expectations . For example, you said the your FCC model is behaving as if it were a CE model. Do you have both FC models? If not, upon what basis can you make that claim?
Even if you do have both FC's you've asked how to properly measure the TX power. You need to get yourself a multiband spectrum analyzer and build yourself a Faraday cage large enough to work inside. You need to obtain the right cables and connectors, remove the antennae and measure the EIRP as close as possible to the transmitter chipset. Radio manufacturers commonly publish specifications whose range performance is theoretical, and based on smooth earth computer models, with no consideration of any terrestrial interference, antenna characteristics, nor atmospheric attenuation.
You seem to be hung up on DJI's specifications, specifically the "FCC" bit. Let's have a look!
Transmitter Power (EIRP)
ModelMR1SS5: 5.8 GHz: <30 dBm (FCC); <28 dBm (SRRC)
ModelMR1SD25: 2.4 GHz: <19 dBm (MIC/CE)5.8 GHz: <14 dBm (CE)
Max Transmission Distance (unobstructed, free of interference)
Model MR1SS5: 5.8 GHz: 4000 m (FCC); 2500 m (SRRC)
ModelMR1SD25: 2.4 GHz: 2000 m (MIC/CE) 5.8 GHz: 500 m (CE)
The 1st thing you should know is that all of these specifications are based on different test methods. Your MR1SS5 lists different specs for exact same device. Why have you not mentioned the SRRC measurement of <28dBm? The SRRC Tx distance is estimated at only 2500m.
SRRC is the State Radio Regulation Authority of China, BTW.
Have a read about SRRC
Next, the MR1SD25 (the CE version) is dual band.....2.4 Ghz & 5.8 Ghz, and has a lower Tx power. Did you know that 5.8 Ghz band suffers from a much greater attenuation, due to atmospheric conditions, obstacles, and over the horizon loss? Its signal loss is enormous, when compared to 2.4 Ghz...that, plus the CE test method actually reduce the max Tx distance estimated to 500m (or 1/8 the distance of the FCC test estimate). Using the FCC model, you're stuck with a radio spectrum that is much more loss prone and directional, with no option to switch to 2.4 Ghz. 5.8 Ghz requires more Tx power, in order to be reliable.
As far as Max Tx distance goes, DJI clearly states unobstructed, free of interference. Why on earth would you imagine being able to reach 4000m distance? Unless you live on a giant cueball in the vacuum of outer space, there is no hope to achieve 4000m.
IMHO, you need to study a bit of radio theory, completely and totally reset your expectations about the Mavic Mini, and chill out a little.
Once again, you are requoting me in a reply, and then referring to "you" throughout the post, when none of the post has any relevance to me or anything I have posted!
Saigondroner
Well-Known Member
I read post 22 as yours, post 29 as yours. I believe your post 33 clarifies you were referring to a Mavic 2’s performance when topic with whole MM range topic. I concurred, that a Mavic And a Mini were totally different.
I did seem to leave a few VN words in error, but don’t think I quoted many times.
Perhaps. A bit of thread-nausea occurred.
I did seem to leave a few VN words in error, but don’t think I quoted many times.
Perhaps. A bit of thread-nausea occurred.
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