Tx Upgrade and Spektrum Reliability

[MikeS]

Eifion and Dizz. Yes I tried a few times and got the same results. No Bluetooth on the car radio. I did wonder myself.

Mike

Edited By MikeS on 23/07/2013 08:55:25

[Pete B]

Posted by Erfolg on 22/07/2013 20:45:39:

I thought that a GUID was "Globally Unique Identifier". I would have thought that Spektrum Rx would go into failsafe if it did not see the TX, even on switch on.

With Futaba, it seems to follow the process of going into failsafe, although some Tier 2 Rx take about 5 seconds to do this, others are apparently instantaneous.

As indeed it does with the Smartsafe system:

SmartSafe™ prevents unexpected motor startup when connecting the battery and shuts off the motor if the signal is lost. Failsafe positions for all channels are stored during binding. If the receiver is turned on before the transmitter, the receiver will not output a signal to the throttle channel, preventing the ESC from arming. When the transmitter is turned on and the throttle is placed in the low throttle position, the receiver transmits a low throttle signal to the throttle channel, allowing the speed control to arm. After connection, if the signal is lost, the throttle will go to its preset failsafe position (low throttle), while all other channels will hold their last command.

Spektrum receivers used in complex aircraft requiring many channels offer the choice of a standard user-defined failsafe mode or SmartSafe.

As you can see above, a Spekky Rx won't supply a signal to the throttle channel until the Tx is switched on and connected. If, as you seem to suggest, some Futaba Rx take 5 seconds to go to failsafe when switched on, that's a bit worrying - a lot can happen in 5 seconds.......

Pete

[Dizz]

From what you describe Mike I would say something must be trasmitting when the car radio or ignition is on.

[Erfolg]

I do not know the time , it is noticeable. It is not a failsafe delay, it is a delay in responding to the TX. Once powered up, removing the signal is an instantaneous, failsafe. I assume the start up delay, is some check that what signal it expects to find. What is certain, the motor just sits there, it is the control surfaces that if displaced from neutral, suddenly, go to neutral.

As I said relative to Spektrum, it appears that from time to time, that on start up there is a need to rebind. Why, I do not know, it is not that I am interested or uninterested, it does not seem to be an issue (if it can be called an issue), other than you cannot fly until bound.

The only claim, of interference I am aware of was someone with one of those small cameras, that I was told used 2.4, again for what, I have not a clue, I just remember the surprise when the model came whistling in, taking some seconds to hit the ground.

Most radio signal failures, I take with a pinch of salt, even on 35. On 35, I did mange to burn a motor out, due to poor cooling and long running, which caused a prolonged glitch, the system came back and that was the end of the panic. Again, I know who the problem was.

[FlyinBrian]

It is possible to acidentally press the bind button on a speky Tx when turning on in which case the tx won't find a rx in bind mode but loses its bind to the rx it was bound to. This has only hapenned to me once when my tx was on the bench and I had laid it on top of some assorted servo arms / control horns. This meant I had to rebind.

Bear this in mind when placing your tx on the ground and switching on.

Also I have never seen the lights on the rx flash after turning the tx off then on although it does happen when the rx is switched off/on

Reliability wise I find My JR DSM2 TX and multiple JR and Speky rxs to be very reliable, the only crash I have had in nearly five years of use was due to a flat battery - totally my own fault.

Edited By FlyinBrian on 23/07/2013 12:54:46

[Peter Beeney]

From some practical experience perhaps I can add some additional info to Pete’s succinct and accurate post above, @22/07/2013 20:08:24. With regard to the brown out, the voltage does need to to fall as low as 2.7 volts on an actual measured test, using an AR500 receiver; which is in fact 0.1V lower than at which a 35 MHz receiver stops working, at 2.8 volts. Although other Spektrum and 2.4 receivers may be higher, of course.

Amongst the smaller parkfly and indoor models there now seems to be virtual plethora of different binding techniques, with devices such as the miniature SpeedMaster helicopter automatically self-binding each time you switch it on. The ParkZone/Spectrum bind-n-fly models may have possibly been responsible for some of the ‘losing bind’ confusion. If say a BNF Champ or a Mosquito and presumably any of the twenty or so other varieties in this range are already bound to a tx, but then switched on without the tx on, that usually means just connecting the battery, after a few seconds it will automatically enter bind mode. Once that happens, to get it to function, it has to be re-bound, either to the original or another transmitter. Using a DX5 or 6, say, that’s then just a case of pulling the trainer switch on and then switching the transmitter on. Sometimes it ackles straightaway, occasionally it takes two or three tries before it decides to play with you. So to always maintain contact with these models it’s important to always switch the tx on first. But I’m sure that it could lead an innocent bystander into believing that there are frequent re-binds. However, it can also be an advantage with say indoor models. The tx comes as standard with the servos in the normal, N, position. The models come with all the servos configured to work correctly in this direction; no reversing of the speed controller, for instance. So in a busy indoor session, if there is a spare model and a spare tx lying around, going into a spare model memory or even a memory of another similar model, and then a re-bind can have you flying in a few seconds. Good as it was in many respects, 35 never seemed to have this sort of flexibility. I’ve found in some ways I’ve very quickly adjusted to the many benefits of 2.4…

Regarding the models with the standard binding plug, we’ve never had any reported instances where the bind has been lost for an unknown reason. I suspect if this happens it may partly be down to fiddle-fingers, would say accidentally plugging a servo into the bind slot in the rx cause a blip? I’ve never tried it.

But at the same time it would appear there is a glitch in the system somewhere. Too many folks seem to have experienced unexplained malfunctions, both in this tread and here. I’ve had a curious servo reverse (Spektrum) which came out of nowhere, mobile phones have been mentioned as a possible culprit; I don’t have a phone, but it might still be possible. From the safety angle, I simply treat the model always as if it is going to start up without warning, which seems to have been an adequate procedure in all situations so far.

After reading the Safestart specification I think might just be tempted to ask a couple of casual questions -

When any receiver is switched on without the transmitter on can it send a random startup and continue to run signal to the ESC? Also does Safestart close the motor down on loss of signal, irrespective of how the receiver was bound to the transmitter? In other words, does it now no longer become important to bind with the throttle stick in the closed position? If not, what exactly are the advantages of Safestart?

PS I’ve been doing a little experiment from the other thread, leaving a tx on, a DX6i, and trying to get the servo settings to change within the tx. In the reversing field they were all set to R, reversed, and over time, several days of switching on/off they’ve not changed. Just this moment I switched the tx on again, checked the field, all still set to R so then I removed the battery cover and took one of the cells out, (tx still on), and replaced it. Instantly, with the exception of the aileron servo, they’d all reverted to N, normal. There are two other active memories, and I will check them, obviously, but I’m pretty sure they are still ‘as set’. So this might explain my original servo reversing, now I only have to explain the original battery glitch!!

Just Be Careful out there…….

 

Edit - Sorry, wrong link..

PB

Edited By Peter Beeney on 23/07/2013 14:03:49

[Erfolg]

I think that an issue with most if not all systems is the differences, not only between manufacturers, but between models. At first sight this appears trivial, in reality can be an issue. I have seen or is that heard, where a model belonging to a beginner, in this instance, but could easily have been just a new Tx to the operator, where a model has been set up, only to find that the new settings have not been saved, due to not understanding the save process.

Unlike mobile phones, there does not seem to be a one that has an intuitive interface at present. I personally liken the situation to my eldest daughters "I" phone, which I can use pretty well, it being intuitive at the interface level. My wife and youngest daughter both have Samsing Galaxys, different models though. Guess what, neither is particularly intuitive, worst still, they both have differences in operation.

With respect to radios, I have seen users of Spektrum 6, I think, who have been at sea, trying to adjust I think the 7, it has a roller barrel for setting.

Then I have a Futaba 6 and a 8fg, guess what, yes, you have got it, both are different, in both structures and method of inputting/setting. I have had some one ask, why do you use that piece of junk, when you have that (8fg). My opinion of the 8fg is that it is fine, certainly not intuitive, and you can do an awful lot with it. But it requires sitting down with manual, plodding through and then probably asking the forum, how to do what you want. In addition there is nothing wrong with the 6ex, it just does not have as many features. Neither has a wonderful interface.

Then there are differences in the voltage that you expect to see as being OK. My 8fg alarms at about 6.8v, never above I think 9.6 v after charging. Spektrum users who see these values become alarmed,suggesting you should not fly, as there tx shows something at 13v after charging apparently. These things are relatively trivial, yet cause issues, the lack of consistency.

I now tend not to favour Txs that use aa type batteries, as I know of a couple instances where using Enelop cells, they being the cause of an issue, in that there would appear to be some slight differences in cell envelope dimensions. The differences being enough to cause issues with contact between cells. Once known, the users finding ways of fixing the issue. It seems to be just another potential issue to avoid.

As for reliability, they all seem much the same, that is the number of Spektrums that do seem to go back from time to time. I am just as happy with 35 as 2.4 as both seem to be pretty reliable systems from my usage. But I do not fly DF.

Again I have a beef with failsafe systems. I cannot see them making much difference to safety, giving thanks to God, because I have never to date been aware of a radio link failure. Just as airbags and crumple zones, you hope and do not want to be aware of there intended purpose. Although I prefer a vehicle with the safety features, just in case. I just think the obsession with them is overstated in the effectiveness.

[Peter Beeney]

A quick add-on to my post above. Re: the servo reversing on a cell removal, when I tried this trick on the actual configuration for the model, a Riot, the aileron servo is the only one that’s reversed. And oddly the the aileron servo is the only setting in the tx that doesn’t revert to normal when a cell is removed. So now I’m still perplexed, how did it occur in the first instance? After thinking about it, I realised it wasn’t this tx that I was using at the time, so trying it on the original tx low and behold the servo setting behaved exactly as planned, and reverted back to normal three times out of three.

So this situation can be unpredictable between transmitters, too, understandably, but perhaps more significantly, if one cell holder became slightly less ‘springy’, and there was a momentary break in the supply, if the tx was moved quickly, perhaps, could the setting revert back to normal? With the model in flight, even. Pretty unlikely, I’d say, but a bit thought provoking, nevertheless.

It may depend on how short the break would have be to be to allow this to happen; I’m guessing here, but probably not very long, at least.

PB

[Glyn R]

This is indeed an old chestnut. I have used a DX6i for four years now without a single issue. The wonderful service at Horizon Hobby applies to damaged items. I have sent crashed receivers back for checking , even with a borken case. They have been fixed or replaced FOC. Spektrum still have their model match so you can't take off with the wrong memory set.

Rebinding an RX will not fix a fault. An Rx cannot lose its bind this is a myth.

Failsafe will if correctly sert will reduce the likelyhood of injury to third parties.

Edited By Glyn R on 23/07/2013 18:47:42