Independent tests prove lack of frequency hopping with XPS

[DadsToysBG]

X-jet, we don't know each other, but from your posts I believe you'll continue to test because you want to know. You will do it for your self because that's the kind of person I think you are. Now the question is will you share the test results with the rest of us?. I hope the answer is "yes". I fly 2.4 and would welcome any testing you do on any system. I sell two of the three systems and the more information you give me I can pass on to my customers. I thank you in advance for any information you may want to share with us. Dennis

[snap a saurus]

It will be nice to know the pro's and con's and which system is better because I am planning on switching everything to 2.4 for next season.
For the doubters, please read your post and consider the consequences before hitting the reply button, I do that all the time and many many times I don't post what I wrote.

[Mithrandir]

	Quote: Originally Posted by snap a saurus
	It will be nice to know the pro's and con's and which system is better because I am planning on switching everything to 2.4 for next season. For the doubters, please read your post and consider the consequences before hitting the reply button, I do that all the time and many many times I don't post what I wrote.

Ellie... the answer is simple!!! FUTABA BAby!!! lol.....

But... just a little Un_Scientific thing I did at home... I piled the 2.4 Ghz Cordless (Yes the phone was actively on a call) and the 2.4 Ghz DSL Modem and the FUTABA 6014 2.4 ghz Rx into a pile on the floor... set the Tx to "Range Check" mode and walked thru the house....

It worked fine!!!

[excelpoint]

X-Jet. Looking in from all the way over here in Australia I for one really do appreciate your efforts. It made me stop and think about what I wanted to put in my aircraft. We have already lost 2 planes that I know of over here that were using XPS. I dont know if that was the cause or not but they were both lock out related. Others i know have been rading this and decided not to put thier new XPS modules and RX's in until more info is out. I really do hope you keep going, I'm looking at the FASST modules for my 12Z and would like more info first. Its amazing how the nobs who are bagging you have never offered to take time out of thier own lives to do thier own test to prove you wrong. Keep up the great work mate, I for one definately appreciate it.

[3DDevil]

I dont need a test... my plane crashed with XPS due to lockout... but I sure hope you continue and dont listen to the knockers!! C'Mon mate... ANZAC spirit!!...

[sweetpea]

I for one am very dissappointed. I understand Xjet's frustration, but to come on a public forum and talk about test results with no data, then promise the data.....then throw a 'tude and not produce it because a few folks bash on you?

You have to expect some resistance.....we all can't be Fanboys of Xjet now can we?


I understand XPS admitted the issue but I'm more interested in the setup, procedures and data so that I or someone else on FG can re-create the test.

Then we have
-repeatability
-maybe finding our own fix or seeing if manufacturer fixes work
-being able to test other companies equipment in the same manner (becuase it may pass that all the systems fail here....so then what?)


I'll wait the 2 weeks because I know he has a life outside R/C.....

[jonkoppisch]

jd admitted the issue. I would think that people flying xps would be getting a little worried about their planes and trying to test it themselves or getting after jd to test and post the results. It's not xjets responsibility. He just brought it to light... It is funny that instead of the 'fans' getting after jd for more info they're going after xjet Something about the blind comes to mind

added: this is interesting...

"Oct 20, 2006, 02:04 AM ... · #949
JimDrew
Xtreme Power Systems
Site Sponsor

... Our system does not move frequencies until it is necessary but that could be hundreds of times per second (FHSS). We actually have a DSIFHSS system. The Spektrum system stays on the two power-up frequencies, regardless of what is going on. Our system can change frequencies if it detects a problem at either end of the link. This means that if our system is in a plane flying near a school with 802.11g beaming out on channel 6 through a 14dbi antenna, and that happens to be close enough to the frequency that is currently in use by our system, then our system will switch to a new (less noisey) frequency. Our transmitter might think that everything is fine, but the receiver knows that there is a potential problem and the switch occurs. Total time to switch and confirm is less than 1 millisecond (~860us)...."[/QUOTE]






"Dec 20, 2007, 10:31 AM .. · #52
JimDrew
Xtreme Power Systems

Join Date: Jun 2005
Location: Lake Havasu, AZ
Posts: 4,105
The frequency hop requires a rise in the noise floor over a number of frames. A sudden saturation will reset the noise "counter" and not switch at all...."

[50%plane]

	Quote: Originally Posted by sweetpea
	I for one am very dissappointed. I understand Xjet's frustration, but to come on a public forum and talk about test results with no data, then promise the data.....then throw a 'tude and not produce it because a few folks bash on you? You have to expect some resistance.....we all can't be Fanboys of Xjet now can we? I understand XPS admitted the issue but I'm more interested in the setup, procedures and data so that I or someone else on FG can re-create the test. Then we have -repeatability -maybe finding our own fix or seeing if manufacturer fixes work -being able to test other companies equipment in the same manner (becuase it may pass that all the systems fail here....so then what?) I'll wait the 2 weeks because I know he has a life outside R/C.....

I couldn't have said it better.

Xjet, I'm sorry if any of my post have been offensive, but I cannot agree with you on the basis of your unsubstantiated post.

Other than that, I wish you well.

50%

[LangerLad]

Unsubstantiated?

So Jim Drew himself admitting that there is a problem is just a rumor then?

All that XJet has done is bring it to our attention and was going to carry out some independent testing on the issue and share his finding with us.

If some believe in the Xtreme sales hype then why do they choose to ignore the self same company's admission to some problems?

[ricoalonso]

Kiwi,
If XJet is no longer coming back to this thread and if you (or FG) are planning to continue the test for most spectrum systems, maybe someone can close this one and start a new one with a new title. Pls keep us posted.

Thanks,
^R^

[zoomer260]

	Quote: Originally Posted by LangerLad
	Unsubstantiated? So Jim Drew himself admitting that there is a problem is just a rumor then? All that XJet has done is bring it to our attention and was going to carry out some independent testing on the issue and share his finding with us. If some believe in the Xtreme sales hype then why do they choose to ignore the self same company's admission to some problems?

I agree, this is exactly what happened. I looked at the first few posts. Again. The bashers aren't listening to all the information Xjet posted.

[sweetpea]

I'm one of Xjet's biggest skeptics......but I believed that he caused the system to fail. But not why it failed. And if the other systems wouldn't have failed under the same situation.

It was no surprise to me when XPS came out and said it wouldn't hop as to me this makes sense for the particular situation (not saying that is right or wrong or that it should have been more clear to the consumer)

What I am saying is I want the data. I want to see the variables held constant and those not. I want to see how many times it was done. The exact measurements that were taken. The exact powe rlevels we are seeing. Etc Etc Etc.... I want to see the dry runs (i.e. no interference).

And I want to take that to all the other popular systems (for now that is Spektrum/JR and Fasst).

I want to know if these systems fail in the same test the same way. If they do, then guess what.......2.4 cameras need to be banned from every AMA field that flys 2.4 and some kind of warning needs to be added to all the packages of 2.4 for the consumer

I stopped caring whether XPS hops or not long ago........its about a particular situation that may effect all 2.4 ----with intermittant hopping such as XPS, continous with FASST or picking two freqs such as Spektrum and without the data we cannot look at that!


Also the title here is misleading......what was found is one instance of XPS not hopping. It has yet to be proven that it hops at slow noise rise or doesn't hop. Another test that could be performed with most of variables from the intial test if we had the data........

Now, FG or whoever is going to test has to start from square one.


Why.....because Xjet couldn't handle some critics?

I emplore you Xjet to take your 2 weeks and present the data. I for one thank you for doing the testing.....now lets take it a step further and find out more information

[USN_POPS]

It would seem to me that with the advent of the XDP and it's ability to analyze the Spectrum, someone would be able to take a laptop to the field and monitor the 2.4 band over a period of time, and with various systems in use. I have mine on order, and expect to do just that. We have a number of guys going over to 2.4, and I hope to be able to see the systems work in real time.

[ricoalonso]

That'll be great.

One question I have is: what if the interference was sensed at the Rx side, that being far above ground and able to see (LOS) more noise than the XPD/Spectrum Analyzer which is almost at the ground level? Is the Rx capable of storing some stats and be able to download it to the XPD for analysis? Just a thought.

Thanks,
^R^

[thinkitsntillegal]

	Quote: Originally Posted by sweetpea
	What I am saying is I want the data. I want to see the variables held constant and those not. I want to see how many times it was done. The exact measurements that were taken. The exact powe rlevels we are seeing. Etc Etc Etc.... I want to see the dry runs (i.e. no interference). And I want to take that to all the other popular systems (for now that is Spektrum/JR and Fasst). I want to know if these systems fail in the same test the same way. If they do, then guess what.......2.4 cameras need to be banned from every AMA field that flys 2.4 and some kind of warning needs to be added to all the packages of 2.4 for the consumer

Well sweetpea, since you want so many answers, you better get to work . Lots of questions you have to start answering.
Sorry to see you go XJet. I, like many others, were patiently waiting for your results. Sorry a few couldn't keep their pants on and wait for you to do this in you SPARE time.