Spektrum DX8
Michael Ramsey
Spektrum started making radios for aircraft at roughly the time I began working for MA—six years ago. The introduction included a product that literally couldn't be lived without, only we didn't know it yet. It featured digital spread spectrum (DSS) technology; the hook was that piloting an RC aircraft would be safer and more trouble-free.
Spektrum pioneered a lot in one transmitter that, in many ways, reduced pilot-error issues. This system began doing some of the thinking for us, and that's the true goal of technology: to handle tasks that make flying RC easier so pilots can focus on flying the aircraft well.
The results of the company's efforts spawned, quite naturally, an evolution that the RC community demanded. So Spektrum didn't rest and continued to put more brains behind the 2.4 GHz brawn it currently calls DSMX. Dedicated solely to the RC hobby, leaps in how Spektrum radios communicate to models and pilots have appeared at a rapid rate. We're being spoiled.
The DX8 is an eight-channel system that includes many features pilots have requested, and it comes in a package that enhances the experience of radio control—affordably. An included telemetry system helps us manage our aeromodeling investment further, so remarkably, our aircraft can talk back to us.
The DX8 used for this review came with an AR8000 full-range receiver and a full-range TM1000 telemetry module kit. The DX8 is not available with servos; however, any servo with a three-wire lead and Uni connector will work with the included receiver. A thick instruction manual is nested in attractive, high-quality packaging. The directions are printed in five languages and can make the material appear more complicated than it is—open the book anyway. The section pilots need is approximately 40 pages and covers airplane and helicopter setup and system capabilities in a compressed, easy-to-digest fashion.
Get a Grip
The DX8 is new, yet in some ways familiar. The transmitter case itself is incredibly light but has a nice feel in hand, thanks to rubberized case sides and rear grips. No other transmitter felt this good in my hands. Balance is important; the DX8 will hang level at the neck-strap clip centered on the case. So if you don't use a strap, holding the transmitter for hours isn't a daunting thought.
A 4.8-volt NiMH battery pack powers the DX8, and its capacity is 2000 mAh, which helps keep the transmitter light. The transmitter battery charger is inside the transmitter. To activate it, connect the supplied 14-volt international power supply to the unique charge jack on the right side. The charge system regulates at 200 mA continuously and indicates charge operation with a blue LED behind the orange Spektrum logo-shaped lamp on the front of the case. That charge rate will make batteries warm if left alone too long, so the user needs to monitor charging.
The transmitter will accept a 7.4-volt Li-Poly pack; Spektrum makes a 4000 mAh version for the DX8 (item SPMB4000LPTX) that uses an alternate foam spacer. The same nominal charge rate applies to LiPo packs, but the charging circuitry steps up and will cut input power when sensors detect a full condition. I haven't tried a LiPo in this system yet.
Securely padded under the snap-tight cover is the 4.8-volt, 2000 mAh NiMH transmitter pack. Real-time telemetry can be sent to the high-resolution LCD screen during flight. Critical data is available at a glance, and audio or vibration alarms can be set for status alerts.
The switch-array layout is familiar and offers four three-position and two two-position switches. The top button on the left is a useful option; besides working the bind function, I use it to activate the timer. All switches can be reassigned to perform different functions, and the joysticks can be mechanically tailored for length and tension. Adjustment screws for the ball-bearing-supported gimbals are accessible under the rear rubber grips, so taking the halves apart is unnecessary. The throttle lever can be customized for resistance and ratchet.
By the way, no matter what mode you fly, the DX8 can accommodate it; Mode 2 is standard.
Geek—Not Greek (AirWare and Programming)
I've had every Spektrum computer radio, and the constant has been programming that's human-friendly. The company calls the software AirWare, and even the average RC pilot can probably program the radio without the manual. The SimpleScroll wheel and two push buttons make navigation intuitive.
Two programming menus are reached in easy but distinctive ways. The system menu is accessed primarily to change models or program a new model by pressing the SimpleScroll wheel and switching on the power. Completely navigating the system menu on a new model makes setup go quickly, so don’t skip any part of it.
Through the system menu you tell the radio what type of helicopter or airplane you have by indicating how many servos are used and where they’re located. Once you’ve done that, the system tells the setup menu what options to enable or leave off. As with a modern cell phone, the DX8 does much of the thinking for you, making the technology easier and safer to use.
If AirWare does something you don’t like—such as separating dual-rate switches—you can reassign switches to suit your preferences. Multiple rates and exponential curves are available, as are flight modes that condition surface control, trim positions, and mixing. Flight modes let you flip a switch to change the aircraft's behavior for 3-D versus precision flying, or hotdog versus trainer flights. This functionality is outstanding and simple to execute.
The DX8 is the first RC transmitter I’ve seen equipped with a vibrating alarm. Like a cell phone, you can customize alerts (low battery voltage, flight-mode conditions, throttle-hold, etc.), and notifications can squawk, buzz, or vibrate. All alarms and timers can be configured to your liking. I changed one default helicopter alarm (the one that sounded if the transmitter was turned on with throttle-hold activated), but I leave flight-mode and throttle-stick-position alarms set to both squawk and buzz.
SDI and Telemetry
The Spektrum Data Interface (SDI) is an access slot on the left side for an SD memory card. The DX8 includes a common 128 MB card with multiple uses. SDI permits instant AirWare updates and enhancements, and beyond the 30-model internal storage, more aircraft can be stored on the card. Models can be shared via the card; Spektrum also offers aircraft presets that can be downloaded to facilitate quick setup (such as Bind-N-Fly presets).
You must be a member of the Spektrum Community to make the most of SDI. Registration takes only a few minutes online, and a compatible SD card reader on your PC is required. AirWare maintenance alerts are emailed to registered users, so staying up to date is effortless.
The built-in telemetry on the DX8 allows you to receive real-time information about a model’s battery voltage, signal quality, engine or motor temperature, and more. It all appears on the large backlit LCD screen. The aircraft is essentially talking back to you with critical information. Telemetry confirms battery and system status and alerts you when unexpected conditions occur. Provided sensors measure voltage, temperature, and signal status. The included TM1000 has full-range capability and enough ports to measure a total of four status conditions. Telemetry helps me know the aircraft's condition rather than rely on faith.
Warnings are programmed into the system by popular default, including throttle and flight-mode conditions. Alerts can be customized or added, such as for retract switch position. An RC pilot owes it to fellow aeromodelers to know the status of an active aircraft at all times—telemetry can help prevent crashes.
Experience and Updates
I don’t have to know how Spektrum technology works to appreciate it. I have operated 10 aircraft—fixed-wing and rotor-wing—with my DX8 and have detected no glitches or errors. I’ve flown electric-powered models in crowded indoor conditions and glow-powered aircraft at long range. During four months of testing, Spektrum released four AirWare updates that cured software issues and enhanced or added features to the transmitter. I’ve casually learned the radio by exploring controls and program features; it has helped me learn and try new aspects of RC that seemed too challenging before. “What more could I want in a radio?” is now a harder question to answer than ever.
AR8000 Receiver Specifications
- Modulation: DSM2/DSMX
- Band: 2.4 GHz
- Weight: 0.33 ounce
- Size: 1.35 in long, 1.27 in wide, 0.45 in high
- Voltage range: 3.5–9.6 volts
- Frame rate: 11–22 milliseconds
- Resolution: 2,048
- Intention: Full-range aircraft
- Options: Flight log and telemetry
DSMX to Me
Spektrum claims to be a leader in spread spectrum technology. Because the company develops only 2.4 GHz technology for RC hobbyists, its understanding of our needs appears well tuned. I don't know if Spektrum is the absolute best, but its approach to my needs as an RC pilot is exceptional.
The fact that the commands we put into a transmitter faithfully translate to what we want an aircraft to do gives us the confidence to explore the world of RC. The rest is icing on the cake, and spread spectrum technology has given us much more than a clear signal. The development of 2.4 GHz systems has made RC flying events more fun and successful. When was the last time you heard the cry, “I don't have it!”?
Signal loss seems to be a problem of the past, and I feel better piloting a model at a crowded fly-in or contest. Five years ago, Spektrum’s unique use of the 2.4 GHz band addressed the needs of the RC hobby. Today, thanks to digital spread spectrum, we have crowded the airways at large gatherings such as the Joe Nall Fly-In and IRCHA Jamboree. Events have been congested enough that DSM2 systems experienced limited operation; pilots adapted by flying when airspace was more open.
Without compromising the wideband agility of Spektrum's signal foundation, DSMX technology was developed to withstand oversaturated 2.4 GHz conditions. Best of all, DSMX is forward- and backward-compatible. If you have the DX8, upgrading to DSMX is simply an AirWare software update you can download now. Flying at a packed event (100 or more pilots) has proven to be more secure with frequency hopping. Pilots don't have to upgrade to DSMX to fly safely, but if you buy a DSMX receiver it will talk to your transmitter broadcasting on DSM2. If you want the advantages of frequency-hopping agility that DSMX provides, update your DX8 and bind it to a DSMX receiver.
Spektrum's modification of its signal technology is a natural evolution. What I appreciate as a faithful customer is that the upgrade didn't obsolete my previous investment in having fun with RC aircraft.
—Michael Ramsey
Manufacturer/Distributor
- Spektrum RC / Horizon Hobby
- 4105 Fieldstone Rd., Champaign, IL 61822
- (800) 338-4639
- www.spektrumrc.com
Transcribed from original scans by AI. Minor OCR errors may remain.
