I'm still new to flynig and operating the Mini (this being my first drone and all), so please bare with me.

I've decided to take the drone out for a spin on a large parking lot near my workplace, and I've ran into a few... strange issues.

a) Really poor signal - as soon as I flew ~30m up into the air (so right above me), the RC signal was lost. When on the ground the application showed that the channel in use was "green" and had very little interference... Of course I did remember to open the antennae on the RC.
b) Not flying so high, I wanted to test the RTH feature... which seemed to be absent. On the app I could only select "Land" while "Return to home" was not displayed for some reason (for this test I flew ~10m up and a similar distance away in a random direction). I'm pretty sure the home position was updated when the aircraft took off but I also tried setting it manually from the settings menu.
c) The bottom-center indicator on the app is... a bit bewildering. When the drone was in front of me, it seemed to indicate the drone was behind me (tapping the indicator confirmed this). In general the indicator seemed to be completely wrong, and seems like it cannot be relied on.

Can someone comment on what could be wrong? What could be the cause of the really poor range? Why was the RTH feature missing and why is the indicator so unreliable?

A and C could be many things so I won't even try to pinpoint the problem, but for B the Return to Home can only initiate once the drone is more than 20 metres away from the set home point. In theory, if you're within that distance of the drone you can pilot it back to you yourself or easily see where it auto lands.

Sorry I couldn't help more!

A) male Sure that the long Site of the antenna is pointed at the drone
B) once you are a bit further away ( i think more than 20 Metres ) rth will be available.
C) this is a common issue with this drone and is caused by the rc which Provides magnetic interference Messing up the compass of your phone.

Regarding A, signal below the drone is the weakest.
Regarding C, this is a known issue for some users.

InspektorGadjet Posted at 1-2 03:47
Regarding A, signal below the drone is the weakest.
Regarding C, this is a known issue for some users.

If the drone's receiver / antenna coverage is the weakest on the bottom side then what's the "optimum" path if I want to take areal shots from high above? Or, to rephrase - how far vertically should I fly the drone so I don't get affected by poor bottom-side coverage?

Regarding C: any idea if this is a physical or software issue? If it's a software problem then there's a chance it might get fixed one day, while a physical issue... not so much.

MBender Posted at 1-2 03:58
If the drone's receiver / antenna coverage is the weakest on the bottom side then what's the "optimum" path if I want to take areal shots from high above? Or, to rephrase - how far vertically should I fly the drone so I don't get affected by poor bottom-side coverage?

Regarding C: any idea if this is a physical or software issue? If it's a software problem then there's a chance it might get fixed one day, while a physical issue... not so much.

About issue C;   aircraft orientation works only good if craft is some meters, more than 6 for my devices, away from the RC  AND  if the mobile device compass is calibrated!

I have several devices and they all work good, so no software issue.

And yes, maby some devices never work (well, if i have to belief [ btw: i do belief them ] all the users with problems)

cheers
JJB

MBender Posted at 1-2 03:58
If the drone's receiver / antenna coverage is the weakest on the bottom side then what's the "optimum" path if I want to take areal shots from high above? Or, to rephrase - how far vertically should I fly the drone so I don't get affected by poor bottom-side coverage?

Regarding C: any idea if this is a physical or software issue? If it's a software problem then there's a chance it might get fixed one day, while a physical issue... not so much.

If you want to fly the drone high. try flying like 30-50 meters in distance so you RC Antennas are somehow paralel to the mini ¨legs¨ where the antennas of the drone are...

The compass issue seem to vary from user to user since it is related to your phone compass and not the controller, they may fix this in FW at some point.

A - Flat side of antenna's should be positioned towards drone, in your case, antennas should be parallel to ground. Or it could be urban interference.
B - Need to be a bit farther away for RTH to work.  
C - Make sure not only drone compass is calibrated in an environment that is free from interference (not beside a car, inside a building, on top of parking structure, etc, and also make sure your phone compass is also calibrated.  Also, as others said, could be magnetic interference where you were (cars in parking lot, buildings have steel in them, etc), could be interfering with your drone, phone or both.  Also, that indicator is not always 100% accurate for some users, although for me, if out in a open field, it seems pretty good.

MBender Posted at 1-2 03:58
If the drone's receiver / antenna coverage is the weakest on the bottom side then what's the "optimum" path if I want to take areal shots from high above? Or, to rephrase - how far vertically should I fly the drone so I don't get affected by poor bottom-side coverage?

Regarding C: any idea if this is a physical or software issue? If it's a software problem then there's a chance it might get fixed one day, while a physical issue... not so much.

a) ideally the antennas to communicate optimally should be parallel and facing one in front of the other (RC and drone ones). If you have your drone right above your head and the RC antennas horizontal (which is the optimal combination) the signal will be poor. More and more the drone will be far from you, the better the connection. Of course in this situation you have to rotate the RC antennas vertical.

c) the position of the drone relative to the RC is based on the built-in compass in your phone. The Rc has some magnetic/paramagnetic stuff in it, hence when you insert your mobile in RC clamps the phone magnetometer will be perturbated. That's physics, so no FW/SW solution. In my case it did work making the phone compass calibration with the phone attached to the RC. Of course to use properly the compass/navigator of your phone when you unplug it from the RC, you have to recalibrate the compass again.

emaneg Posted at 1-2 10:12
a) ideally the antennas to communicate optimally should be parallel and facing one in front of the other (RC and drone ones). If you have your drone right above your head and the RC antennas horizontal (which is the optimal combination) the signal will be poor. More and more the drone will be far from you, the better the connection. Of course in this situation you have to rotate the RC antennas vertical.

c) the position of the drone relative to the RC is based on the built-in compass in your phone. The Rc has some magnetic/paramagnetic stuff in it, hence when you insert your mobile in RC clamps the phone magnetometer will be perturbated. That's physics, so no FW/SW solution. In my case it did work making the phone compass calibration with the phone attached to the RC. Of course to use properly the compass/navigator of your phone when you unplug it from the RC, you have to recalibrate the compass again.

The thing for me is that when I open the compass iapp in my iOS device, it shows correct readings. Connected to the RC also does give correct orientation, and it doesn asks for a calibration.

Hi. Thank you for reaching out to DJI Forum. First, I would recommend to please try flying the drone in a different location with less interference like power line, radio tower and metals to isolate the issue. Second, upon take off with Home Point recorded. If the drone is less than 20 meters away from Home Point the option available will be the landing button. Finally, regarding the orientation concern. I will forward this concern to our DJI designated team for further attention. Please refer to the image I will be posting for more details regarding RTH. Thank you.

InspektorGadjet Posted at 1-2 11:20
The thing for me is that when I open the compass iapp in my iOS device, it shows correct readings. Connected to the RC also does give correct orientation, and it doesn asks for a calibration.

Well, I'm not deep into the phone compass technology. I've read it can be based on magnetometer, and in this case the physics is crystal clear: if you modify the magnetic field where your magnetometer is, the readings will change. If other techniques are used (accelerometer, gps, ..) no interference has to be expected.
Any iOS nerd can give some hint?

emaneg Posted at 1-3 03:15
Well, I'm not deep into the phone compass technology. I've read it can be based on magnetometer, and in this case the physics is crystal clear: if you modify the magnetic field where your magnetometer is, the readings will change. If other techniques are used (accelerometer, gps, ..) no interference has to be expected.
Any iOS nerd can give some hint?

I had the compass app asked me for calibration before, specially after not being used for a long time.
But it hasn´t asked for one since I have the mini.

InspektorGadjet Posted at 1-3 03:22
I had the compass app asked me for calibration before, specially after not being used for a long time.
But it hasn´t asked for one since I have the mini.

i don't know what triggers the calibration procedure: time interval? Divergence between compass and accelerometer readings beyond a given threshold?...?

emaneg Posted at 1-3 03:28
i don't know what triggers the calibration procedure: time interval? Divergence between compass and accelerometer readings beyond a given threshold?...?

No idea, would be great to reset calibration at any time.

InspektorGadjet Posted at 1-3 03:35
No idea, would be great to reset calibration at any time.

Not sure if this is of any help but I found how to enable compass calibration in ios:

Step 1: Open Settings, choose Privacy, click Location Services and tap System Services.

Step 2: Enable or disable Compass Calibration. To enable the setting, hit the switch on the right of Compass Calibration to turn it on.
Step 3: To disable Compass Calibration, click the switch to turn it off

I've done some more flying. The compass... well, that one's a hit and miss. I had instances where it worked fine and instances where it did not. If the app uses the phone compass then I acknowledge that strange things can happen. I don't know why, but I expected the RC to have stuff like that built in.

The RTH issue was, indeed, me not realizing I need to fly away more. Thanks for the information and, well, now I feel silly.

The signal strength is something I still need to check. Again, I haven't done many flights yet, but I did manage to take the Mini for a spin over the weekend. First time around my GF was adamant that we use the propeller guards (she's a bit... panicky), so the Mini went into payload mode and I couldn't really fly far away anyway and over the short distance we did fly there were no issues. Today we went flying again, this time without the guards, and while signal strength was initially very good, it seemed to drop very suddenly once I flew up into the air ~100m (and a good deal away horizontally). Given that the signal strength was OK and then suddenly it wasn't is it safe to assume it was some kind of interference?