Spektrum have had some 6 months now in which to build a customer base, indeed reports indicate they’ve done well, the DX7 being hard to get hold of in a UK market where demand has outstripped supply. Of course, it was only a matter of time before one of the established R/C manufacturers joined the party, so let’s welcome the new Futaba 6EXP, a 2.4GHz version of their recently upgraded 6-channel computer system.
2.4?
I’m sure you’ve read RCM&E over the last few months so I’ll assume you’re not a stranger to 2.4GHz systems. I won’t give a blow by blow account of the technology although it’s increasingly accepted that the 2.4GHz frequency will come to dominate the way in which we control our models in the future.
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2.4GHz is a solution to the historic difficulties that we’ve grown to accept over many years. It promises to drastically reduce interference, eliminate switch-on shoot-downs, improve model responsiveness, prevent flying with the wrong model memory, and make frequency control issues a thing of the past.
COMBO OR FULL SET?
The Futaba 6 EXP transmitter is supplied in two versions, the first packaged with a NiCad and charger, along with the new R606FS receiver, the second as a full set with switch harness, receiver NiCad, charger and four 3003 servos. Clearly the combo is aimed at flyers who want to try 2.4GHz without acquiring the other bits and pieces although when you stop to think, the extra £20 is good value for the servos, switch and battery.
QUICK GLANCE
The 6EXP introduces some new technologies, systems and words that will be unfamiliar. The basic operating system is called FASST. This stands for Futaba Advanced Spread Spectrum Technology. It differs from the Spektrum system in a number of ways but perhaps most significantly where the Spektrum system locks on to two spare channels for the duration of the flight, the Futaba system occupies an individual channel for only two milliseconds before moving on to find another.
Another word for you: Pre-vision. What does it mean? Well, it’s Futaba marketing speak that labels how the technology looks ahead for potential problems by scanning incoming data and applying error correction. This, we’re told, results in a solid, impenetrable link between transmitter and receiver. Moreover, each transmitter has an individually assigned identification code that the receiver must recognise before it will operate. Once the link between the two is made the receiver stores the code and becomes ineffective with any other transmitter.
The link procedure starts with the Tx and Rx being placed within one meter of each other. When the Tx is switched on a green light at the back of the set indicates that an RF signal is being sent. With this the receiver is turned on and a tiny switch on the casing held down for one second to start the linking process. A solid green LED light on the receiver signifies that the process is complete. In practice I found that the receiver took just a second or two to complete the task.
R606FS
It’s pretty obvious that this new Rx is where the Futaba R&D budget has been directed. At just 4cm long, 2.5cm wide and 1cm deep it’s incredibly small and weighs next to nothing. More significantly it’s a full-range unit designed to operate with any model from a park-flyer through to large petrol aerobats, EDF jets and gas turbine powered behemoths.
Unlike the DX7, the R606FS doesn’t require a satellite receiver, although the two 13cm aerials protruding from the case are longer than the DX’s four 6cm antennas. Of that 13cm the first 9.5cm is coaxial cable whilst the remainder is antenna. The instructions provide guidance as to how they should be positioned in the model, although the advice basically suggests that the two cables be positioned at 90 degrees to each other with the antenna elements kept as straight and as far apart as possible to maintain the effective range. The unit can handle any Futaba compatible servos and 6 volt currents, although, as always, it’s important to check that the your chosen servos are happy to operate at 6 volts.
TRANSMITTING
A modified version of the existing 6 EX system, the new EXP is a 6-channel transmitter with 6 model memories, aircraft or helicopter options and many of the now standard computer system functions we take for granted. Incidentally, the flying mode is selectable so a few button pushes can convert the transmitter to mode 1, 2, 3 or 4, according to preference.
The function line-up looks like this:
For helicopters there’s:
The most obvious difference between the 2.4GHz and 35MHz version is the aerial, the 6EXP having a small, stubby, 10cm long antenna that’s hinged at the base. A little care needs to be exercised here as this particular aerial doesn’t feel hugely robust. Futaba suggest that, in operation, it’s placed perpendicular with the ground, although in testing, having accidentally left it straight, I didn’t notice any deterioration in range. That said, it’s clearly very wise to follow Futaba’s advice on matters such as this and not take any unnecessary chances.
At the back of the case, the battery hatch hides a 700mAh NiCad, above this is a standard Futaba trainer socket and the RF signal LED mentioned earlier. Main stick lengths are adjustable but the rear of the case must be removed to alter or disable the throttle ratchet. Stick tension on the remaining axes can’t be altered.
If you remove the rear case you’ll see a switch in the top left-hand side of the set alongside the word ‘France’, printed on a piece of circuit board. Flicking the switch allows users to operate the unit in yup, you guessed… France where, apparently, a slightly different band width is in use compared to the rest of Europe.
A CASE IN POINT
The case front is little different to the old 6EX. Standard two-way subsidiary function switches adorn the top, the main sticks and digital trim selectors are where you’d expect, and programme buttons are scattered around the small LCD screen at the bottom. A rather understated throttle-cut button also sits alongside the screen where it can’t be accidentally triggered by unwary beginners. The LCD itself is clear enough although the amount of information shown within the diminutive display is very limited.
You’ll be pleased to learn that the 6 EXP comes with a fail-safe function, albeit applied only to throttle. As is common with fail-safe settings it can be programmed to either move the servo to a pre-determined setting or hold it in the position of the last healthy signal. A battery fail-safe is also employed to monitor the receiver battery voltage and move the throttle to a pre-set position or fast idle if it should drop below 3.8V. Incidentally, it should be noted that the 6EXP can’t be used in a ‘buddy’ training function with a Futaba transmitter that has the old, round socket.
PRACTICALITIES
The receiver, whilst small, feels very robust. Little grommets protect the aerial cables as they exit the case and Ripmax tell us that in use they should be as robust as any aerial you’ll find on a standard 35MHz Rx. Some small receivers feel pretty fragile especially as far as the connector pins are concerned but again the R606 doesn’t share these traits. The more I’ve handled it the more impressed I’ve become.
Installing the receiver in my WOT4 was easy
As you’d expect, the main task where R/C installation is concerned is to correctly position the receiver aerials in the model. Although the R606 is light enough to fly small electric aircraft, the ability to get the antenna into a satisfactory position may dictate the size of aeroplane that the unit operates. I started with my WOT 4, a subject with sufficient space to allow a textbook layout for initial testing. Here, the receiver sat happily in the middle of the fuselage with masking tape used to position the aerials against the fuselage side and forward bulkhead.
AVIATION TIME
A low power output is required for range testing and to achieve this the menu button should be held down at switch-on. The screen confirms the status, after which 60 seconds are made available to check for normal control response at 30 – 50 paces. In truth the first flight with my WOT 4 was a bit of a non-event as nothing unusual happened. I took off, flew as far away as I dared, circled a spot at our site where glitches have been known to occur, then thrashed the model around the sky before landing. Uneventful is the word I’d use, which is exactly what I was hoping for.
Some 3 months down the line – I now prefer holding this transmitter!
It’s fair to say that the transmitter felt different in use, which I’d attribute to the imbalance of the shorter aerial compared to the traditional 35MHz version – the 6EXP is a very light transmitter it should be added. Subconsciously a part of my mind was willing me to reach forward and extend the thing. It’s nothing I won’t get used to and after a spell of flying 2.4 I’m sure that the longer aerials will feel equally odd.
Now, I tend to fly electric models during the summer months and it is in electric flight applications that I believe 2.4GHz technology will supply the most tangible and immediate benefits. High-powered electric aircraft do seem to provoke glitches and ‘spikes’ from time to time and since some of my models entertain me with such, I decided that it was time to pop the R606 into a ‘leccy model to see how it fared. The first steed was a Seagull EP Decathlon whilst the second was the SebArt Katana. Both have flown very well on the system with no problems whatsoever. Once again, flying has been a bit of a non-event, which is all I could ask for. Finally, I really couldn’t truthfully say that I’ve experienced an improved degree of ‘latency’ or lock-in with the 6EXP although perhaps that’s just a reflection of my flying ability!
WELL?
Futaba have been making industrial 2.4GHz R/C equipment for 15 years so I guess they must be pretty familiar with the technology by now. It’s fair to say that the 6EXP is a good value system, albeit with a facility suite that’s reflected in the price, i.e. a modest number of model memories, the small screen and the limited fail-safe capability. Mind you, I know many happy 6 EX owners who only ever wanted a simple system at a competitive price and the radio clearly meets their needs. I’m hugely impressed with the R606 receiver; It’s so incredibly small and yet so very robust. To endow this little gem with full-range capability across any model type is quite a feat of electronic engineering. What’s more, the set-up and range testing process is very easy and it hasn’t missed a beat in the air. With that, I guess there’s little more to say. The system has passed the acid test and, when you think about it, that’s all you really need to hear.
OCTOBER 2007
Four months have passed since I wrote the words above. In that time I’ve flown using both this new system and my Futaba FF9 which transmits on 35MHz of course. My 6EXP 2.4 hasn’t missed a beat during which time I’ve used the system almost exclusively in higher powered electric models. In particular I’ve flown the SebArt Katana all summer using the system.
Here’s the receiver in the Katana fuselage – plenty of room here!
Now I don’t know if it’s me, the state of my mind or some sort of self-suggestion but the more I fly 2.4, the more I do actually feel it is a little more ‘locked-in’ than 35MHZ, just a little, but enough to be just noticeable. I’ve become thoroughly used to the small stubby aeriel and now the longer FF9 aerial seems strange and cumbersome!
The position of the aerial is something I’ve come to ignore, more through forgetfulness than intent but I’ve often landed only to find the aerial pointing straight ahead – the model has never flown any different which ever way the aerial is pointing.
Battery endurance from the modest 700mAh NiCad fitted to the transmitter is acceptable enough for me although a larger capacity pack would have been nice. The transmitter case never ceases to remind one that it’s not top of the range but in a funny sort of way I’ve grown to like the honest simplicity of the 6EXP, it does what it does perfectly well and at a price that many find acceptable. It is very light too which is great if you don’t like using a kneck-strap.
I now own three 2.4 receivers (R606) and have just ordered another two as I start to replace my ’35’ gear – not a task I can afford in one hit! I’m not sure if I’ll buy a 2.4 plug-in module for my FF9, the little stubby ariel looks a little strange coming out the back of the Tx (asthetics mean a lot to me you know!)so I may hang on and look at the 2.4 version of the FF7 when it arrives.
As far as I’m concerned 2.4 is here, it works and it’s totally reliable. Once you’ve used it, like me (and many others) I really don’t think you’ll be looking back.
