I decided to buy a drone (part two)

The next step was buying the chosen drone. I had seen enough videos from Mavic Mini owners to know that this was the drone for me. The problem was that this model is so popular, stores can’t keep it in stock. I finally found a store that would commit to ordering me one and I got it in early January. I was hoping for a mild day to give it its maiden flight, and then Calgary got hit with a week-long arctic cold spell. I made the decision not to test fly the drone until the weather got milder, as the batteries don’t do well in cold and the manufacturer doesn’t recommend flying in sub-zero temperatures.

Even though I couldn’t fly right away, I still wanted to unbox the thing and do any software related things that needed to be done. I bought the ‘fly more combo’, which in addition to the drone, a battery and the controller, gets you 2 spare batteries, a smart charging station with fast charge brick, spare props and joysticks, a prop guard, and a case. It’s a great value to get the combo. I’m glad I unboxed on a day I had no intentions of flying, because some things were not exactly intuitive.

The batteries have a weird locking mechanism that I could not figure out without reading the manual. Manuals. Who knew? But seriously, even videos online didn’t talk about proper battery removal. Maybe I’m just getting old. Once I understood how it worked, the rest was easy.

Turning the controller and the drone on and off was not intuitive either. And it’s not just me. I saw many people complaining online, wondering why they weren’t able to turn the things on. It turns out that there is a trick to it – of course. Once I figured out the trick, I was able to do it. You would think the manual would give you some hints on what to watch for, but no. Just in case any Mavic Mini owners are reading this post (the rest of you can skip to the next paragraph), it requires a quick 2 second press of the power button, followed by a one second pause and then pressing and holding the button and watch the power LEDs sequence on to an audible beep. The same goes for shut down, except that the LEDs sequence off.

I realized that there was no way I was going to be able to remember all of this, so I started my own manual of tips for old guys like me.

Once I had charged one of the batteries enough, and charged the controller, I turned the drone on to try pairing the drone to the controller using the phone app (DJI Fly). The app paired the drone to the controller and I made an account with DJI. The first order of business was a firmware update for the drone, which took about 3 minutes.

Based on the countless videos I had watched, I knew I would probably have to do a compass calibration. I was correct. Thankfully, even though the instructions don’t make it perfectly clear how to do that, the videos I had watched helped a lot. In essence, you have to, when prompted, rotate the nose of the drone around all points of the compass, then rotate the belly around all points of the compass (nose up).

So now I’m ready to fly, as soon as the weather improves. While I waited for the weather to get above 0 C, which is the recommended minimum for flying this model, I watched a lot of owners of the Mavic Mini give their tips on what to watch for when flying this drone.

It quickly became obvious to me that flying a drone is not as easy as you might think. You have to really be fully conscious of the area you intend to fly in. You have to be aware of tall objects, power lines, trees, transmission towers, cell towers, bridges, etc. You have to be aware of other aircraft in the area, even other drones. You also have to be in tune to the weather.

What makes this particular model tricky is its low mass. Unlike a drone that weighs several kilograms, a 249 gram drone is going to get thrown around in more than 15 km/h winds. In fact, the Mavic Mini can only resist wind speeds up to a maximum of 28 km/h. So you have to be aware of the current wind conditions in your flight area and also take into account that the higher you fly, typically the windier it gets. Thankfully, the drone will let you know through the controller and software when the conditions are not good for flying, but once you're up there, if the wind gets unexpectedly strong, you need to know what to do to safely get your drone back to where you are. This typically means getting the drone to a lower altitude fast, hoping that the lower altitude doesn't interfere with the signal to the drone, and making a beeline to your location without hitting anything. Needless to say, it is always a good idea to situate yourself downwind from your intended drone flight target, so that you can return WITH the wind rather than against it. I watched a few videos of pilots thinking there was no wind and then painfully watching as their drone fought headwinds trying to return to base. I have heard countless tales of pilots who have crashed or lost their drone in bad wind conditions. There is an app for that by the way. The UAV Forecast app gives you fairly accurate weather conditions for your current location and a synopsis of whether conditions are good for flying. I have also heard people offer the practical advice of getting a cheap anemometer to check actual wind speed where you plan to launch from. I think it goes without saying that you probably don't want to risk flying your drone on anything other than a full battery in windy conditions either, as the amount of power needed to fight the wind is substantial.

DJI did a few things to make the Mavic Mini as light as it is. They did away with any collision sensors that you would find on a bigger drone. It has optical sensors on the underside for sensing ground movement, ground distance, and landing conditions, but there is nothing stopping you from flying your Mavic Mini right into a tree, or bushes, or a building, or tower, or power lines. So total awareness of the drone's surroundings is a must. Considering how far this drone will fly from you and the controller, people can get cocky and try to see how far they can wander. This is incredibly risky, as you would have no idea if you were getting close to any physical obstacles. They recommend keeping your drone in visual range and there's a good reason for this.

Based on what I've seen from reports of crashes of this drone, the biggest mistake pilots make is not adjusting the return to home altitude before they fly. The drone has a safety feature called 'return to home'. The idea is that if you encounter trouble, getting the drone home is a button push away. While this sounds fantastic, there is a bit of preparation to pull this off successfully. Before I get to that though, there are some things that will trigger a return to home (RTH) automatically. Low battery will prompt you to RTH, but you initiate it manually according to the manual. Needless to say, you never want to get to this point. If the drone loses connection with the controller for more than 11 seconds, it will initiate its own RTH sequence. If you lose the video link, you'll be prompted to initiate a RTH, manually. You can choose to fly the drone home based on the map and compass indicator.

What makes the RTH feature work properly are 2 critical settings. You have to set the home point. Every time. The drone has to know where to go when the RTH is initiated. You can change the home point mid-flight, but you have to have one. But you also have to properly set the RTH altitude. For every flight. Because if the RTH gets triggered and the RTH altitude is 20 metres, and there's a 22 metre tall tree, or a 40 metre tower, or a high bridge between the drone and the home point, the drone is going to fly right into it. So the RTH altitude has to be set high enough to get over every tall obstacle in its RTH path. You may not get to choose when the RTH feature will be triggered, so you really have to have your act together. But you also have to consider wind. The higher the RTH flight will be, the windier it will be as well. Situational awareness is key.

Another thing many people don't truly understand is how the drone communicates with the controller. Again, unlike more capable drones with fancy radio links, the Mavic Mini uses good old fashioned WiFi. Although the higher WiFi frequency of 5.8 Ghz is pretty decent, it still can suffer from too much interference from other WiFi sources. So if you're trying to fly in a crowded urban environment, you may have sudden interference that will render your drone temporarily orphaned from its controller. You can go into the settings and manually choose a quieter WiFi channel, but this is a dynamic situation. One thing you can definitely do to make things a bit easier on your drone is to turn the WiFi on your cell phone off. You are typically using the phone attached to the controller as its video screen, and transmitting on WiFi right next to the controller's antennae is not the best idea.

Another thing people need to know about WiFi is radio frequency propagation. I've watched a few people online complain about WiFi interference with their drone, but witness the real reason they are experiencing signal issues. Don't get me wrong, if you're trying to operate a drone in an area with a lot of signal, you're going to have potential for problems. But you also have to do the drone a favour with your antenna direction. If you think about the antenna as a pole, the signal doesn't propagate out the end of the pole, it propagates out the sides. So, visualize a cell tower. If you look up at the antennas, you'll notice they are all vertical. Your controller's antennas should be vertical too. If you are holding your controller in a way that doesn't point the signal toward the horizon, you're going to have issues.

19 April 2020. That was the day of my maiden flight. I just couldn't wait any longer, I had to get this thing up in the air.

The first flight was short, fairly low altitude. I just wanted to get a feel for how it flies, how stable it is, and how it lands. I felt good about how that went, so I sent it up a second time and went a bit higher, but stayed close. Glad I got that out of my system.

I timed it perfectly in terms of not bothering anyone. A lot of people bring their dogs to the park I took off from. In future, I might have to get further away from the road so that I get more warning if people are approaching, so I can bring it in for a landing.

I took a couple of videos, here's a link to the second one.

So far, I'm cheating big time in my production choices, because I'm trying not to spend any money on video editing software. Little did I know, you can use Windows 10's built-in Photos app to make videos. I used it and was able to add a soundtrack (royalty-free music by www.bensound.com). The Photos app is definitely not as feature-rich as I'd like, but it's free. I finally got the audio fade-out figured out after 2 versions of this video. I have to do my video editing first, determine the final duration of the clip, then get a properly edited soundtrack file made separately with a proper fade-out before inserting it into the clip. Audacity to the rescue!