Spektrum DX6i (user review)
The Spektrum DX6i rc system brings 2.4GHz radio control technology to the beginner / intermediate flyer, at a very affordable price. Having recently purchased a DX6i, it's only fair that I share my thoughts by way of this 'user review' with you, and hopefully help you decide whether this system is for you or not!
Spread spectrum rc technology is relatively new to the hobby (at the time of writing), but is rapidly becoming commonplace. The introduction of this new 2.4GHz technology was the biggest shake-up to happen in radio control since the introduction of FM radio systems in place of the original AM ones.
Incidentally, the name spread spectrum is actually the vague generalisation of the technology; to be more specific there are currently (2008) two brand 2.4GHz rc technologies; DSM / DSM2 is used in the Spektrum and JR systems, and was the first spread spectrum technology developed for rc use, while FASST is Futaba's equivalent. In case you're wondering, they stand for Digital Spectrum Modulation and Futaba Advanced Spread Spectrum Technology respectively.
It goes without saying that the number of manufacturers producing 2.4GHz radio control systems will increase with time, and I'm sure will come up with their own branding for the technology they use.
By far the biggest benefit of spread spectrum rc technology is that it's virtually impenetrable to outside interference, because of the way the transmitter communicates with the receiver; radio signals are sent from Tx to Rx, as in FM systems, but that's really where the similarity ends.
This interference-proof system is of course perfect for rc use. No more do you have to worry about someone else turning on a transmitter of the same frequency, no more do you have to remember to put your peg in the club frequency board - with 2.4GHz, it's just switch on and fly!
The other benefit is speed of communication between Tx and Rx. The signal is instantaneous, and when coupled with the better quality digital servos, the model response is immediate and precise. To the average club flyer, this will probably go unnoticed but to a competition 3D champion it's a massive and welcome improvement over previous systems.
The Spektrum DX6i - overview
The DX6i is sold as a beginner / intermediate rc system suitable for the majority of rc airplanes and the smaller electric helicopters.
Developed from the successful DX6, the DX6i bridges a gap between basic 4 channel rc sets and overly-complicated 7+ channel ones. At around the $200 mark, it's an affordable set that offers more than enough functions and features for the average club pilot.
What's in the box?
The basic Spektrum DX6i package can vary from country to country, but the core components are the transmitter, receiver, bind plug and batteries. The difference between countries comes in the type of battery supplied. My Spektrum DX6i (purchased in the UK) came with disposable cells i.e. non-rechargeable, but I believe that US-spec DX6i's come with 4 rechargeable NiMH cells and an overnight wall charger.
I have read complaints about separate disposable cells being supplied with such a radio set, instead of using a soldered pack, with users drawing a comparison between the DX6i and toy rc transmitters because of it. That's fair enough I think, and indeed I did buy 4 good quality high capacity NiMH cells to use in place of the ones supplied. But, the advantage here is that you can carry 4 top brand cells with you as an emergency back-up, and change them in a second should your NiMH cells be getting low.
While on the subject of batteries, 2.4GHz rc systems are more efficient than the previous FM technology, and so can operate on lower voltage. This is why the DX6i takes only four AA size cells, as opposed to the usual 8 required in FM transmitters.
First impressions show the Spektrum DX6i Tx as a nice piece of kit, with all the right sticks and switches in all the right places. On picking it up for the first time though, you may see and feel it as a bit 'plasticy' and not particularly macho. But the overall feel is comfortable, and everything falls naturally at or within easy fingertip reach.
A 60mm x 25mm LCD screen is bottom center of the Tx, to the right of which is the DX6i's unique feature, a vertically aligned roller wheel with which you access all the programming functions. It's very simple and intuitive to use, just click and roll to scroll through the various menu options.
The toggle switches on top of the Tx are Mix/Throttle Hold, Rudder Dual Rate, Gear/F-Mode (flight mode, normal or stunt for helis) and finally the Trainer switch. On the Tx face, the switches are Elevator Dual Rate, Flap/Gyro and Aileron Dual Rate. In addition to these 3, there is a Throttle Cut button, a nice touch for immediate motor shut-off in that emergency situation!
The toggle switches feel good and solid, and the main stick movement is smooth. These two main sticks are adjustable in length, and the tension is also easily adjustable from inside the transmitter. This is something that I did straight away, as the throttle stick was way too easy to move in my opinion, and a lack of ratchet on this stick means higher tension is definitely required.
The trims are digital, with a seemingly good range - certainly more than enough for initial flight tests until servo horns and rods are adjusted accordingly.
But as nice as the DX6i Tx is, there are a few things that let it down in my opinion...
Firstly, the black sides of the body are textured for grip, but they are still hard plastic and so the surface is not slip-proof. A rubber compound material would have been much better here, but presumably that would just up the price of production. Second, the main power switch feels cheap with a bit more movement than just a definite on/off click.
Another gripe is that the top mounted toggle switches are labeled with small adhesive stickers that look like they could peel off at any moment, and my final whinge is that the battery compartment cover is in no way secure. The catch does not engage well and so the cover can be slid off without even trying. Having said that, the batteries do seem a very tight fit between terminals, and I think it's highly unlikely that the cover will drop off and a cell will fall out - I hope!
So, although the Spektrum DX6i transmitter isn't perfect, it is perfectly adequate for those of us who haven't yet risen to the heights of professional rc flying! Maybe the overall impression is a bit 'plasticy', but we have to accept that there aren't many products around these days that do ooze quality. And for the price, I think the DX6i is a good deal.
The receiver supplied with the Spektrum DX6i is the AR6200, which is Spektrum's 'middle-of-the-road' Rx, with full range capability and suitable for the majority of electric and gas airplanes and helicopters.
The AR6200 is actually a pair of receivers; the master Rx into which everything connects, and a smaller remote Rx connected by a 150mm long cable.
The reason for this is simple - double security! Because it has two separate receiver units, the AR6200 can be mounted in the model in such a way that the antennas can be perpendicular to each other and at different locations within the model, thus absolutely maximising the ability of the receiver to receive the signals from the transmitter.
And on that note, the Spektrum DX6i does actually broadcast its signal on two different frequencies within the 2.4GHz band, which further doubles the security. If for any reason (highly improbable) that one signal is temporarily lost, the other one is still being received by the Rx.
The AR6200 aside, there are several Spektrum 2.4GHz DSM2 receivers that can be used with the DX6i, namely the micro-sized AR6000, AR6100/6100e and the AR6300 for Park Flyer and micro helicopter use, and the AR6200, AR7000 and AR9000 for full range use in larger aircraft. These latter three are all dual-Rx receivers each having a master and slave unit.
Incidentally, the difference between the single receivers and the dual receivers is in the range. The smaller Park Flyer ones do have a limited range and should only be used in smaller electric airplanes and helicopters, while the larger dual-Rx ones will continue to receive the transmitter signal long after your model has flown out of sight.
This small item is essential for binding the receiver to the transmitter so that only that specific Rx will respond to the Tx signals for that model. Each separate receiver must be bound to one of the ten model memory positions on the Tx and, once bound, will only respond to that exact choice of model from the Tx list.
When binding, the transmitter emits a digital code unique to that model memory, which the receiver learns and stores. The code is one out of billions of possible codes and this is why a bound Rx will never respond to Tx signals meant for another receiver. The binding process only takes a few seconds to complete, and only has to be done once.
Binding instructions are clear in the manual, but you may not be able to follow them exactly if your DX6i bind plug only has either male or female Rx connector, and not both. The manual states to connect the bind plug to the charging connector of the switch harness (which, incidentally, is not included in the DX6i set...) but if both bind plug and charging connector are the same gender, then you need to follow Plan B, which is...
- Make sure the desired model memory (1-10) is selected on the transmitter
- Turn off the Tx
- Connect the bind plug to the Batt/Bind slot of the Rx
- Connect the Rx battery pack to any one of the 6 remaining slots on the Rx, via the switch harness
- Turn on the switch to power up the Rx, check for flashing LEDs inside both receiver units
- Turn on the Tx while pulling the 'Trainer' toggle switch towards you (very important!)
- Wait a few seconds for the Rx LEDs to stop flashing and stay on continuously
- Binding process complete!
- Turn off Tx and Rx
Spektrum DX6i features
For the majority of 'sport' rc flyers, like myself, most of the DX6i's programming functions probably won't be used. But Spektrum have allowed for most possibilities and probabilities, and have included all the popular functions in the DX6i. In no particular order, these include...
- 10-model memory
- Dual and exponential rates
- Dual aileron / elevon / flaperon / V-tail mixing
- Servo reverse
- Travel adjust
- Timer / Alarm
- Trainer mode
- Gyro adjust, graphic throttle curve, graphic pitch curve, P-mixes, Revo mix, Swash type (Normal, and CCPM 120) for helis
- Range checking
Beware the Manual!
Probably the biggest let-down in the Spektrum DX6i package is the 'instruction' manual.
While it looks chunky and full of everything you'll ever need to know, it is in fact no more than a very basic guide to accessing all the functions and features on the DX6i. In fact, it merely tells you what you could probably learn just by playing with the transmitter for ten minutes!
The manual does not tell you how to program your model correctly; presumably Horizon Hobby view this as potentially just too big an area to cover given the number and variety of models that the DX6i will be used on. For specific programming info, it's either a case of trial and error, getting the info online or phoning the HH support number and crying for help!
In summary: the Spektrum DX6i is, in my opinion, a good value rc system for anyone who flies rc at a Park Flyer / club level, either small to medium size helicopters or airplanes. Making the jump to 2.4GHz technology is without doubt the right thing to do, and this particular radio set offers a great opportunity to do that.
While its quality may not be top-of-the-tree, it is perfectly acceptable and good for the money. And coming from the JR factory, so to speak, it's an rc system with a proven pedigree behind it.
If you are of beginner or intermediate rc experience and want to 'go 2.4GHz', you could do a lot worse than add a Spektrum DX6i to your shopping list!