In the Beginning...
In the beginning, the R/C Gods created “AM” for transmitting signals to aircraft and surface vehicles. AM has survived in surface vehicles, but is no longer used in aircraft for a number of reasons, not the least of which is AM’s inability to provide a stable, secure and glitch-free signal to pilots. After AM, along came FM and with it a reduction in flight mishaps due to radio conflicts and signal variances. PCM (Pulse Code Modulation) addresses many of these issues and is the standard today in standard radio control aircraft. PCM has saved a lot of pilot bacon and will continue to do so until someone develops technology like that in the DX6, but with greater range capabilities.
What makes the DX6 so revolutionary is its use of a special frequency band that sits well above the interference frequencies generated by speed controllers, pushrods, metal vibrations and other model-generated signals. That frequency is contained in the 2.4 gigahertz frequency band; the same band we use in cordless phones and other home electronics. According to the Federal Communications Commission, products that operate on 2.4 Ghz must have frequency scanning capability along with the ability to avoid conflicts among other 2.4 Ghz devices. For Spektrum™, however, the FCC rules were not enough, especially with safety in mind. Spektrum™ began with the standard specifications on a 2.4Ghz system and beefed it up with “Dual Frequency” locks. Dubbed “DuaLink™” by Spektrum™, the DX6 system automatically scans the 80 available channels in the 2.4GHz band and selects the two frequencies with the least amount of activity (I’ll tell you why it picks two in a minute). That is just for openers. Once the system finds the two best frequencies, it adds a GUID (Globally Unique Identifier) layer of security so that the receiver only “listens” to the one transmitter using the two identified frequencies and the correct GUID. With more than 4.2 billion GUID codes, I am prepared to bet the farm that nobody within thousands of miles will have your combination of channels and GUID. That combination makes for an extremely secure and private channel on which only your transmitter and your AR6000 receivers can communicate. Once your transmitter and receiver are on the “same page,” you never have to reset them unless you want to alter the fail safe settings in your transmitter. Otherwise, the system is “locked in” on every flight. You can turn your transmitter on at home or at the field without worrying about shooting down anybody’s plane or violating your club’s safety rules. The power is intoxicating!
The system is infinitely scaleable because you can bind to your transmitter as many AR6000 receivers as you wish.
Itty Bitty Antennae
What really grabbed me about the Spektrum™ were its demur profile and itty bitty little antennae. Notice that is plural. There are two antennae on the DX6 receiver for several reasons.
- In order to prevent the signal from fading as the aircraft changes orientation, the receiver has two antennae. This ensures that at all times at least one of the antennae will be receiving crisp signals from the transmitter.
- The two antennae actually receive signals on two completely different channels! Recall that the DX6 selects the two least active channels during its initialization. The transmitter uses these two channels at all times to simultaneously transmit identical signals to the receiver. One signal goes to one antenna and the other to the second antenna; both with equal strength, clarity and security. If it helps, think of the receiver as two receivers, the ultimate in redundant systems! If one antenna ever “drops” a signal for even the briefest time (more than 15 milliseconds to be exact), the other antenna will fill in, ensuring a consistent signal throughout every flight.
On the transmitter, the antenna is also very short and curiously bendable. Why does it bend up to 90 degrees (so it points straight up if you are holding the transmitter flat)? The answer lies in how the DSM receivers pick up signals. Surprisingly, pointing the end of the antenna directly toward the aircraft provides the weakest possible signal. On the other hand, directing the shaft of the antenna toward the airplane provides the strongest signal. So, bending the antenna has the effect of directing the shaft of the antenna toward the aircraft when you hold the radio in a typical manner. This is a very simple, but effective feature that illustrates just how much thinking went into the design of the DX6 system.
Direct Flights: No Hopping
Some readers may be thinking that the DX6 technology is just a re-hash of frequency hopping spread spectrum technology, which uses extremely fast channel hopping to avoid other systems (think about it, if everyone is using a hopping radio that changes channels every few milliseconds than nobody will be on the same channel for longer than a few milliseconds). Although channel hopping is a clever way to avoid “stepping on” other radio signals at the field, its prime disadvantage is transmission speed. Hopping systems have a slower feel, something that Spektrum™ eliminated with its DSM (“Direct Sequencing Spread Spectrum”), which promises (and delivers) a very “tight” feeling of control over the model at all times.
Buttons, Switches, Sticks and Programming
The DX6 is awesome in its roll as a crystal-less park flyer radio. But it also provides great training for hobbyists who have yet to ascend to computer radios. The system is programmable, but not to such an extent that it will overwhelm users. Like most users, I started fiddling with buttons long before I cracked open the manual. The menus were mostly intuitive, but with the book, they were downright simple. Even for those who have trouble setting the clock on their VCR or microwave, this radio is easy to program. We highly recommend that you do use the manual, which contains a “Quick Start” guide divided into “airplane” and “helicopter” setups. For more complex programming (such as mixes, wing type settings and dual rates); each function has its own section in the manual, complete with screen shots and step-by-step instructions.
The DX6 introduces a new type of button to transmitters; a quick contact button (we dubbed it that). This circle button (there are two; one for trainer mode and one for throttle cut) allows you to quickly activate either the trainer mode or throttle cut by simply tapping the button. The buttons require enough pressure to prevent accidentally triggering, but not enough so they are hard to activate mid-flight. The other switches on the transmitter are easy enough to reach and may be assigned to different combinations functions!
One of the “killer features” on the DX6 is its helicopter program. The DX6 can handle throttle and pitch curves, CCPM, and revolution mixing. This allows you to use the DX6 for micro helicopters like the Blade CP and also larger electric helicopters like the T-REX.
On the airplane side, you should have all of the mixing features you need for a park flyer. With aileron-to-rudder, elevator-to-flap, differential, flapperon mode and v-tail setups, we can’t imagine a disappointed park pilot. For hard core 3D pilots, you will have to get by without rudder dual rates, but you can’t have it all in a $200.00 radio package. For the money (and ignoring the money), this is a huge value.
The Future of Transmitters
Does the DX6 represent the future of our hobby? It very well could. Ideally, our aircraft systems should all be capable of selecting their own open frequencies, blocking out unwanted signals and operating with the reliability and redundancy that Spektrum™ has built into the DX6. Although the range of the DX6 is insufficient to comfortably or safely fly a standard radio control aircraft, its use in the park flyer market will not only make all forms of flying safer, it will also prove that the DSM platform is the platform of the future. Until Spektrum™ hammers out the issues with longer range transmission, pilots can revel in tomorrow’s technology by flying their park fliers today with the DX6 Park Flyer System.