Independent tests prove lack of frequency hopping with XPS

[wrightme]

Toumal, my point IS that the distances of TX and RX matter. The bench test IS repeatable, but not relevant for real-world flight.

Your response and viewpoint is relevant and well-spoken. Your response has NOT been the "norm" in this (or in other) thread.

I agree that there have been more than one such report of uncontrolled servo movement, it hasn't been scrutinized to a reason, merely pointed out as a problem with XPS. If it WAS a "problem with XPS" as many like Dust allege, each owner of XPS would experience it. Since each owner doesn't experience it, the answer must be something other than a specific problem with all XPS units.

[Dustflyer]

	Quote: Originally Posted by wrightme
	Dustflyer, Did you ever test anything more than one TX and one RX module in your "twitching" videos? If not, you used a sample size quite a bit too small to determine usability. With my 3 TX modules, and about 5 in-use RX modules, I have never experienced the symptoms your videos show. It is quite likely that: 1) one of your modules was faulty 2) the TX to module connection was faulty

Yes I did.

I sent the first receiver and transmitter module back to XtremeLink for exchange. The new ones did the same thing.

Regarding the transmitter:

1) The transmitter was in perfect working order. The reason I bought XtremeLink in the first place was a crash I had on 72mhz. Spektrum modules were not yet available, XPS was the only game in town. After the crash I immediately sent the transmitter in for checkout. Hobby Services reported it in perfect working order but they changed a few parts anyway, mainly the pots. If you followed my threads on RC Groups you will recall JD telling me my problem was dirty pots. My pots were not only clean, but brand new.

2) I installed a Spektrum module in the transmitter and it worked perfectly. I successfully flew my H9 33% Cap with it. Never had a problem. Never a twitch, completely unlike my experience with XtremeLink.

3) Yes, you may recall JD offerring to "check out" my 9Z WCII transmitter or even buy it outright. That is true but I refused. Once I let that transmitter go he could have done what ever he wanted to it. To me it made no sense to give away my transmitter or have it "checked out" since I had already done that and it worked perfectly with Spektrum.


I have no problem with people using XPS but in good conscience I believe I have to at the very least warn them of the risks in doing so.

I strongly believe it is foolhardy to fly anything in the vicinity of spectators with XtremeLink. Why subject yourself to the liability considering all that is known about it?

There are people in the world who do risky things and use those activities to express their individuality and set them apart from everyone else. Standing by something like XPS is one of those things. It might not be the best judgement but it fullfills a need.

[Toumal]

	Quote: Originally Posted by wrightme
	I agree that there have been more than one such report of uncontrolled servo movement, it hasn't been scrutinized to a reason, merely pointed out as a problem with XPS. If it WAS a "problem with XPS" as many like Dust allege, each owner of XPS would experience it.

Not necessarily. It might be caused by local RF interference on the channel that XPS chose. That interference might not be present everywhere. I'd imagine that if those people were to check the band with a frequency analyzer or a WiFiSpy2, they'd see something out of the ordinary on the 2.4 band.

[Dustflyer]

	Quote: Originally Posted by Toumal
	Not necessarily. It might be caused by local RF interference on the channel that XPS chose. That interference might not be present everywhere. I'd imagine that if those people were to check the band with a frequency analyzer or a WiFiSpy2, they'd see something out of the ordinary on the 2.4 band.

That is a very interesting point you are making. I have always suspected right from the beginning that XtremeLink has a problem with interference and is unable to rectify the problem in certain cases.

I always had glitches around my house or in my garage with XtremeLink. I also have a video showing the same weird stuff in the local schoolyard using the prescribed range test procedure which in the early manual was with antenna off. Out at our flying field I got a good range test with XPS but was too skittish to fly it.

On the other hand I have never had a glitch with Spektrum anywhere, even in the exact same places I got them with XtremeLink. I have even done a range test with the airplane in my garage with just enough of the tail showing to see the elevator and rudder move then going outside with the transmitter with no clear line between antennas and still got a good range test.

Bottom line is Spektrum works when XtremeLink doesn't. Your theory may be correct: I may have some weird 2.4Ghz energy around my house. If that is the case I have proven beyond doubt that in difficult environments Spektrum works when XtremeLink doesn't!

Here is the infamous schoolyard video. The range test procedure in the early manual called for 100', antenna off, prog button pushed. In the video I elevated everything on an empty cardboard box with nothing around. But I did not push the prog button! So even at full power it failed the range test in perfect conditions!

[E_ferret]

	Quote: Originally Posted by wrightme
	Dustflyer, Did you ever test anything more than one TX and one RX module in your "twitching" videos? If not, you used a sample size quite a bit too small to determine usability. .

Hi Wrightme,
You seem to forget that first bad experiences are how we condition ourselves.
Admittedly some people are slow to learn, they are the ones with lots of scars.

First time as a child that you burn yourself on something hot, you try not to do it
again. Asking dustlfyer to spend time and money to try to find a 'good' tx/rx
combination is a bit much!
You must admit that is the case of XPS, being used mainly in planes, a bad experience tends to make an impact, pardon the pun. There are many case in life
where first bad experiences are enough. (i was sick from eating brains at age 8, never tried it again regardless what excuses my mother used!)

I still fly with XPS , but then my body carries a lot of scars too.

[skubacb]

Dustflyer: On the twitching with a 9Z. That was resolved long ago. Ridiculous to act like it is something new. The 9Z has a slightly different output than a 9CAP. That oddity has not been seen on anything but the 9Z.

Hoping: Now we come to the crux of it. When I see the post that says, But it should hop on saturation. Well, it was never advertised to do that. So proving that it does exactly what it is supposed to do is NOT proving that it does not hop.

Aircraft (racing) not going into failsafe mode: I have tested the failsafe of XPS by taking an aircraft to altitude and turning off my radio. Aircraft within 1 second went into failsafe mode. I have tested all my other 20 RXs for failsafe while the A/C was on the ground. In every case and condition the aircraft went into failsafe mode. I firmly believe that if a RX does not go into failsafe then either it was improperly programmed or there was another failure on the aircraft.

Indeed I would like to see the hoping scheme changed. I understand and hope we will see some changes in the next update. However, hoping or not does not seem to be a factor. The system works to the limits of my eyesite (20/15).

As far as safety of the systems: If you apply the same criteria to FASST and Spectrum then they should not be in any aircraft. QQ has now lost control of two aircraft in front of crowds. Multiple Spectrum aircraft were lost at SEFF. Spectrum has delinked on two of my aircraft. Another Spectrum equiped aircraft was only giving me bits of control (like the old time glitching) until after about 20 seconds full control was regained. FASST continues to overheat. Seems Futaba is waiting for the Fall and cooler weather to give us an answer. So if the criteria is any loss of control on any aircraft then not one system today is qualified for flight.

As I tell my new flying students. Getting an aircraft in the air is wonderful. Getting it back in one piece is a bonus. (That goes for any system, since I have seen aircraft go down flying every system available today).

[XJet]

	Quote: Originally Posted by skubacb
	Hoping: Now we come to the crux of it. When I see the post that says, But it should hop on saturation. Well, it was never advertised to do that. So proving that it does exactly what it is supposed to do is NOT proving that it does not hop.

It's not about hopping on saturation -- it's about hopping when encountering *any* interference strong enough to cause the RC link to be lost.

Saturation *wasn't* an issue in Kiwi's tests -- it's something that JD brought up to try and cover the gaping hole in his own story and the deficiencies of XPS.

If it does hop, why did JD faithfully promise a video showing the hop but only deliver a poor attempt to trick people by exposing Futaba and Spektrum to 10 times the field-strength that he exposed XPS to and then claiming XPS was "better" (even though that very test again proved a total lack of frequency agility)?

[wrightme]

	Quote: Originally Posted by Toumal
	Not necessarily. It might be caused by local RF interference on the channel that XPS chose. That interference might not be present everywhere. I'd imagine that if those people were to check the band with a frequency analyzer or a WiFiSpy2, they'd see something out of the ordinary on the 2.4 band.

But since the person in question did not do such a test, we will never know, and ANY such allegation is simply speculation.

[wrightme]

	Quote: Originally Posted by E_ferret
	Hi Wrightme, You seem to forget that first bad experiences are how we condition ourselves. Admittedly some people are slow to learn, they are the ones with lots of scars. First time as a child that you burn yourself on something hot, you try not to do it again. Asking dustlfyer to spend time and money to try to find a 'good' tx/rx combination is a bit much! You must admit that is the case of XPS, being used mainly in planes, a bad experience tends to make an impact, pardon the pun. There are many case in life where first bad experiences are enough. (i was sick from eating brains at age 8, never tried it again regardless what excuses my mother used!) I still fly with XPS , but then my body carries a lot of scars too.

I do not seem to forget, as you state. Conditioning and learning are two different items. If we only rely upon pain/pleasure conditioning, or conditioned response learning, we ignore the cause/effect problem solving that the human brain allows. Conditioning is the animal side of our psyche. Problem solving is the human side. I choose human.

Facetious but relevant example to follow:

Walk across the carpet and get shocked on the doorknob. Learn from the conditioning to NOT open doorknobs!
Can you detect the flaw in the conditioning?
Such a response is typical of an animal. A human can go beyond the conditioned learning to the cause/effect problem solving to understand that it is OK to open the doorknob, after determining that dry air + carpet = static electricity.

OR, he can just buy a different brand of doorknob that doesn't shock him. (of course, the competing brand is made of plastic instead of metal).

[E_ferret]

	Quote: Originally Posted by wrightme
	I do not seem to forget, as you state. Conditioning and learning are two different items. If we only rely upon pain/pleasure conditioning, or conditioned response learning, we ignore the cause/effect problem solving that the human brain allows. Conditioning is the animal side of our psyche. Problem solving is the human side. I choose human. Facetious but relevant example to follow: Walk across the carpet and get shocked on the doorknob. Learn from the conditioning to NOT open doorknobs! Can you detect the flaw in the conditioning? Such a response is typical of an animal. A human can go beyond the conditioned learning to the cause/effect problem solving to understand that it is OK to open the doorknob, after determining that dry air + carpet = static electricity. OR, he can just buy a different brand of doorknob that doesn't shock him. (of course, the competing brand is made of plastic instead of metal).

Hi Wrightme, I agree with the lot! Just one tiny tiny little thing; why would you open a doorKNOB?

[ss40]

	Quote: Originally Posted by JEFFRO503
	This is a good thing you haven't lost an aircraft to XPS! The place where you fly might be at a very low noise area , which hopefully gives you years of trouble free flying. Some of us aren't so lucky. If you we're to take a bunch of time , you could read through this entire thread and see that there have been a bunch of reports of people losing their airplanes , and we're ALL having probelms with the XPS system ( Except Sweatpea.....who mentioned he never really could prove it.) As big as this thread has gotten , it would probably take a couple days to get through it , but it is a great read for sure. I'm not an expert of FHSS , and in fact i know very little about it. Just from everything i have read here on this thread and some other threads on other sites , i'm starting to get a grasp on how this stuff actually works. I probably have about 1% of the knowledge that some of these guys have when it comes to this stuff. BUT.....I DON'T need to be an expert to see that my aircraft is having probelms. I consider myself a pretty good pilot , and can see when things are not working correctly. The only reason i ever got involved in this thread was because i wanted to see if "ANYONE" could make XPS hop......so far at 103 pages of debating.......NOBODY has ever made the XPS system hop....EVER! Only a claim by JD , that he had gotten it to hop , and AGAIN........no proof what so ever. Now.....IF you we're to read through this entire thread , you would read about more aircraft meeting their doom to an XPS failure then any other system out there. In fact , there are more completely destroyed aircraft in this thread alone , than all the other systems combined , in any other threads i could possibly find. There are some guys whom jumped ship over here to FG , from RCG , because they we're getting flamed for stating problems , or just asking a question.......Hell , they we're lucky to even be able to keep their post up..........JD would just delete it! OF COURSE you read about more XPS failure here...........JD isn't here to delete the post. God....what a horror story!

I have read through this thread from the beginning and over time and I understand more than you(per your lack of knowledge stated by you) and for you to say more models have been lost to XPS than any other systems is complete nonsense! That is the nonsense I am counteracting here.
I find your assumption about my knowledge and assuming I didn't read the thread to be insulting, however I will let it go at that.
This past weekend I had starange behaviour on a fairly new model, very "touchy" acting extremely weird, doing uncommanded things. People said the air was very unstable but I found that hard to believe. Got someone else to take it up and he immediately did a quick landing and wanted no part of it. Further investigation showed the an aileron servo moving completely erratically, slow, fast , opposite direction. This is the second Hitec servo acting like that(brand new). The other was last year on 72Mhz and a different Hitec servo model. Anyway, had I crashed, we were leaning toward "radio problems"...turned out not so.

Had a similar event with a friend at a float fly about a month ago. Another Hitec servo caused him to think he was glitching with his Spektrum setup. Luckily he landed and we were able to show the servo was no where near centering properly for him. That would have been a Spektrum failure.

I am not denying that there could be some problems with XPS and I am not denying that tests have failed to show "hopping" but there have been some absolutely ridiculous claims of problems with XPS with no concrete proof what so ever and I have a difficult time accepting that type of behaviour.

I have a wireless network in my home and neighbours do too. There is a wireless internet service that I used to use in the neighborhood with a repeater station near my home and the main transmitter a few miles away and about 1000 feet higher than me and our field. It is fairly powerful as I was using the main TX as my internet source until they installed the repeater station. I am sure the area is not jammed full of 2.4 but this is not a silent environment I am operating in.
The Spektrum guys at our field are not encountering anything either.

For the quote a few pages back that people are "pis*ed" that they were lied to by a manufacturer. They should really grow up. In my 6 decades I have been lied to by many manufacturers like IBM, HP , DEC, Microsoft, etc. etc. Ford, GM.... and on and on. I would not rant on the internet every day for months about it. Life is too short. 2 heart attacks and quintuple bypass have proven that to me.

[Woketman]

	Quote: Originally Posted by ss40
	For the quote a few pages back that people are "pis*ed" that they were lied to by a manufacturer. They should really grow up. In my 6 decades I have been lied to by many manufacturers like IBM, HP , DEC, Microsoft, etc. etc. Ford, GM.... and on and on. I would not rant on the internet every day for months about it. Life is too short. 2 heart attacks and quintuple bypass have proven that to me.

You are UNREAL!!!! You are basically saying that we should give this butt-hole JD a pass for lieing to us!!! MAN, where were you when I was trying to sell beach-front property in Kansas? Perhaps you don't mind being lied to by the manufacturer, but most of the rest of us are reasonable and we don't like it!!!

[Toumal]

Scubacb: This is the third time I've read you writing a reply that ignores either everything or parts of what was said earlier. For the 10th time:

We are not talking about hopping on saturation. We are talking about hopping on interference. Kiwi's test does not saturate the receiver, it merely occupies the same channel as XPS, and XPS fails whereas Spektrum and FASST keep working without a hitch. What part of that sentence is it that is unclear or, after Kiwi's video, remains open for debate? Why is saturation being brought into this over and over?

@ss40: If video evidence is not good enough for you, then I suggest you test for yourself. It's not hard to do, and it's the only way you can be sure that what we say is true. As for being lied to by the manufacturer... I dunno about you, but if I buy a 25C LiPo pack, and it dies when I pull 20C, then that pack goes back for replacement or I get my money back. When a car is advertised with 2 airbags but they don't inflate on a crash, that car is going to be recalled. Since frequency hopping is an important safety feature on a free-for-all band such as 2.4, I'd say this is something no responsible model pilot should just ignore out of convenience.

[socalsal]

	Quote: Originally Posted by Woketman
	You are UNREAL!!!! You are basically saying that we should give this butt-hole JD a pass for lieing to us!!! MAN, where were you when I was trying to sell beach-front property in Kansas? Perhaps you don't mind being lied to by the manufacturer, but most of the rest of us are reasonable and we don't like it!!!

Wow.you are really mad at this JD... I can understand this. However why would you call anyone such names??? All this does (name calling) is cheapen your image in the eyes of others.
You have the right to say anything you want . However don't you feel that letting this subject degrade to name calling is going a bit far?

[socalsal]

Question> can a system be made to "hop" just by re-writing the software?? or is it a hardware issue?

My thoughts are if it is a software issue then would it not be a simple case of updateing the software to enable a system to do this?

If it is the software what is preventing someone from writing a "update" and providing it to others?? are there some type of laws against it??