Although we have never met (for obvious reasons) I have the utmost respect for your opinion and knowledge of electronics...
You old smooth talker you!
Where to begin. Do you have a spare couple of days?...
Spektrum versus Futaba. We're treading on thin ice here because no matter how much thought has gone into wording my own opinions, the problem of upsetting owners of certain R/C equipment will always be there; no person likes to hear that their particular brand of Tx is inferior to other brands, so my opinion is simply just that - an opinion, and not necessarily the same opinions of other folk. All I can offer is an unbiased view of the good points, along with the bad points, of R/C equipment and leave it for yourself and others to make up their own minds.
First off, you mentioned gliders. Straight away you have caught me on the hop because I have never programmed any radio for glider operation. I know that both Spektrum and Futaba encorporate programming parameters especially for gliders, but it's not something that I ever had cause to use. My one and only experience with electric gliders was not exactly fruitful, so I ended up dumping the glider on fellow forum member Bob (Young at 60). I'd mentioned in a previous post that I owned a DX7 for a while, but I didn't have it long enough to fully delve into the menus for glider setups. For all I know it may well indeed handle that particular aspect with flying colours. On the other hand, I can tell you that the Futaba 9C Super does in fact cater very well for every parameter covering just about every type of glider available.
Secondly, you might consider the build quality of each radio. In my opinion this is where the Futaba leaves the Spektrum standing. Again, I've already mentioned Molex connections throughout on the Futaba 7C and 9C radios onwards, whereas the Spekky Tx has all of its off-board wiring connections simply soldered-tacked to copper pads on the main circuit board. Futaba also goes one better by using separate PCBs for all their toggle switches and rotary pots, again each PCB interconnected to the main PCB via sturdy Molex connectors. Spektrum have opted to simply solder any off-board wires directly to the contacts of the toggle switches, etc... and not even as much as one piece of heatshrink tubing in sight.
Gimbals: Futaba have very cleverly designed a simple plate which is attached on the rear of the throttle gimbal mechanism. The idea being that you can quickly and easily swap the plate on to the other gimbal should you prefer to have the ratchet throttle on the right-hand side. There is no need to fuss around with installing springs and all the usual hassle associated with a self-centering stick because the spring is already there. The plastic plate simply pushes the self-centering spring away from the gimbal, while at the same time a 'click' ratchet comes into play. It's hard to describe without actually looking at the design, but all in all it's a very clever move on Futaba's part.
The gimbals on the Specktrum do not move as far as the Futaba gimbals from their centre positions. In effect, the limited movement of the Spektrum gimbals give an overall less movement on the servo horn. You can dial an extra bit of servo throw from the programming menu, but from my own point of view I'd sooner have the gimbal mechanically travel farther than it actually does, and then have the option to reduce the amount of servo throw via the menu system if necessary.
2.4GHz: Futaba employ their FASST system, while Spektrum employ their DSM system. Now without getting too deep into the technicalities, the FASST system (again just my own personal opinion) is far superior in every way. I still feel that Spektrum's Spread Technology system is very clever stuff, but also feel that they rushed their ideas before fully putting the system through its paces. I'll probably get shot down in flames for saying this, but I've lost count of the number of complaints whereby Specktrum owners have suddenly lost the binding between the Tx and the receiver(s). Many Spektrum owners have also reported that the stored parameters of each model have suddenly been erased from the memory - for no apparent reason at all. And, of course, there is that somewhat strange case of the lower amplitude pulse on the throttle channel (see later).
Of course, Futaba equipment has not been without a few teething problems as well, but in all in all I can honestly say that of the three Futaba system failures which I've witnessed, two of those have been due to pilot error (even though they won't admit it), and the third error was caused by the careless attitude of the owner; he had stored his model and the battery pack in a cold, damp shed throughout the Winter, which eventually caused the so-called dreaded 'black wire syndrome' between the battery switch and the receiver. It was a crash just waiting to happen.
Question time: So on the strength of this...
Would I install Spektrum equipment in a model airframe? Answer: No.
Would I install Spektrum equipment in a fast nitro boat? Answer: No.
Would I install Spektrum equipment in a run-of-the-mill boat for simple R/C use? Answer: Yes - probably. But I would be constantly fretting about losing the binding, or model memory suddenly going belly-up.
So you're probably wondering if I'm biased towards Futaba equipment, to which the answer is yes, absolutely, without doubt. Besides, in the case of the 9C and 9C super, one has the option to delve into the so-called Service Menus, and from therein one can do all sorts of customised tricks. (Futaba does not make this knowledge freely available, probably because it's likely one could frazzle the main microprocessor).
Scroll up the page to reply #9 from 6705russel. Grok the first photo. Do you see the small badge in the top-centre of the radio just above the middle rotary pot marked "CAMPac"? Located behind that badge are 6 wire connectors. With a bit of jiggery-pokery it is possible to talk with the microprocessor and you'll get to see several pages on the LCD which are normally reserved for Futaba's service engineers only. From there you can do all sorts of nifty things. For instance, you can swap all the 2-position toggle switches for 3-position toggle switches. Just that one simple modification alone can add a zillion more options in the user menus. The clever thing is that all the hard work is already done for you - the software is already tucked away in the processor - you simpy have to tell it what's what and it happily does all the tricky work itself.
Finally, grok the attached image. What you are seeing there is the signal pulse train taken from the trainer socket on the rear of the radio. Look at the line of blips on the centre line of the graticule - there are 9 in total. The first blip is the start of the usual 20 milliseconds framerate - the so-called sync signal, followed by eight more blips. If the oscilloscope were wider you would see the same sync blip 20mS later.
Now look at the 8 pulses shown beneath the blips on the graticule centre line. The reason they are beneath the centre line is because Futaba employ their standard negative shift (otherwise known as 'low shift'). Other makes of transmitters sometimes employ a 'high shift', in which case the eight channel pulses would be ABOVE the row of blips on the centre line. Each of these pulse are the 8 channels of the 9C, all roughly set to 1.5 milliseconds length. The first pulse from the left-hand side is Channel 1 - the Elevator pulse. Channel 2 is the Aileron pulse, channel 3 is the throttle pulse, channel 4 is the rudder pulse and channels 5 through 8 are the auxillary channels.
The only reason for all this bumph is to let you see that the voltage (or height) of each pulse from the centre line are all the same amplitude (the same voltage), which is exactly how it should be. But, and here's the spooky part, when I 'scoped the pulse train of a DX7 recently I noticed that the amplitude of the throttle pulse was much lower than all the other pulses. Why? Well, your guess is as good as mine. Perhaps, as I said in the previous post, it might be something to do with how the owner had programmed a toggle switch on the throttle channel to work as a 'kill' switch for his glow engine. Or perhaps the radio itself was one of those 'Friday afternoon' jobs, perhaps a one-off dodgy transmitter. Who knows? All I know is that it didn't look too encouraging. I programmed the same scenario into the 9C, yet the throttle pulse remained at the same amplitude as the other 7 pulses.
You mentioned that you are considering selling your DX7's. Please don't do that on my say-so. If you're happy with your Spektrum gear, and it works for you, then by all means give it the tender loving care that you think it deserves. After all, there are many hundreds of Spektrum owners on this forum alone and each one are perfectly happy with them.
