Independent tests prove lack of frequency hopping with XPS

[Kiwi]

Guys,

My scanner melted under some extreme conditions and the boys have shipped me a replacement. I'm pretty sure it was a voltage spike that got the unit so I cant blame the tool, maybe me.

Also I have now secured a second radio (Futaba 8UAPS) so that allows me to run consecutive tests from more than one system running concurrently. The Spektrum 7 channel radio is here, all the other systems are here and tested actually but I want to hold back on the results until I have the abillity to run all the systems at the same time to see how user friendly they are and if I can get XPS to hop. So far it has refused to budge but I have been unable to run FASST along side it as I had just one radio.

Hang five guys. I hope to have some serious info to post this week.

Next week (12th to 16th March ) I am out as we have our big event and we have QQ, JASON S, FRANK N and ALAN SZABO in town and I will not be missing that for anything.

[jonkoppisch]

	Quote: Originally Posted by sweetpea
	... As it appears the system did hop. As Xjet states; depending on why it hopped it may not be the most robust method. I'll grant him that until we have more proof. In the same breath though until we can prove it didn't actually hop this thread has been busted (on the premise the system didn't hop) The system hopped (at least onece) in flight with no ill effects to the user....

I quite disagree. I appears that it MIGHT have hopped. No one is 100% sure so as far as the thread being busted, I think we're far from that. On top of that, if the only way that the system will hop is under specific circumstances, ie, you have to be in the same location as fasst, with exactly the right angle, with exactly the right voltage, hop on one foot then the other etc... Then that really doesn't count as a plane saving channel hop does it? A hop should be defined as if interference is experienced on the current frequency that you are on and there are other clear frequencies available then the system should transfer to that freq.... FAR from busted... It would be nice to also request the same proof as has been demanded by the fb's of video etc to back the usable hop...

[BaldEagel]

I don't know if my system hopped or not, but I do know it scared the hell out of me, took off and initiated a right circuit the turn carried on even though the stick input to correct too level flight had been applied, eventually the plane responded and all seemed normal on responce times for approx half the circuit, the delayed responce happened three more times whilst I was bringing the plane around for a landing, only just managed to miss the ground on one freze out, I managed to bring her around and landed, these freeze outs where happening approximatly in the same place's that PPM Rx's get glitches on our field, the field is on marsh land miles from habitation, but on an estury that has wireless communication towers on either side, the glitch areas are approximatly in line with these towers, incidently these towers are not in sight, but have been plotted from Ordinance Survey Maps.

My conclusion is that flying XPS/Graupner IFS system is like flying PPM except you get position hold instead of glitches. At my age this amount of excitement is too exhausting, I now have a Spektrum module in my Zap and no freeze outs or holds of any kind have been experienced on the same field in the same positions.

Mike

[Kiwi]

OK,

I have finally managed to get some results after weeks of computer issues and a wife wondering if I had a new lady in my life at night.

Man what a marathon. But I have a screen capture video of the test on XPS and I jabber on a lot I know, but hopefully its understandable.

It is repeatable, no I was not looking for failsafe or glitches. The test was to make XPS hop.

I did not, it would not and it won't. I actually think it just plain cannot.

Go here for the results as this thread is way too long for others to find this.

http://www.flyinggiants.com/forums/f...tml#post408254

[BaldEagel]

Kiwi

Brilliant stuff, just the sort of information/ammunition we need to get this thing sorted once and for all and all of us, thanks for doing all the hard work.

Mike

[buttface]

Yea I always knew that XPS crap was junk after mine and my buddy's failed .He lost a turbine jet and I almost lost a 40%er!

[Flyfast1]

There's a guy over at RC Groups that has posted a video of the XPS system changing channels in response to interference. He used a 2.4 Gig video transmitter as an interference source. He shows his XPS system going into failsafe and then he has full control, even with the camera still transmitting. It would be even better if he also had a spectrum analyzer or even the XDP to show the channel change. It's interesting.

-Ed. B.

[DadsToysBG]

I watched that video and for the life of me I couldn't make any since out of it. I saw the servos lock out, but I couldn't tell if it hoped or what or even f the servos moved again. I watched it several times. It proves nothing to me. Dennis

[Flatlandman]

This is not knocking Kiwi as a person just a scientist. Im not dis proving his statement or saying his tests are bad just incomplete. He did about 3 test that prove what we already know and then came the blanket statement that xps wont change channels. Its like me getting my sister to shoot 3 free throws with her missing those 3 and using that info to tell you that she will never make a shot from any range. This is the problem i have with this test and many others. If your gonna say it wont do something you need to have more than what i see that Kiwi has compiled. If Xjet ever tested this i think from reading his previous posts that he would go further and more complete.

[aviti]

OK, say it does hop when you stand on your head with three transmitters aiming at each other and your fingers crossed, who cares? Don't people find the marketing just the slightest bit misleading? Hell, I figured it wasn't frequency hopping when I saw the asterick * by the feature in his advertising.

Do I know enough to understand if a 2.4 system needs to hop or be on 2 channels, nope, not really. But I just figure if JR, Spektrum, Futaba and Airtronics couldn't make a system reliable on just ONE channel, then why can Jim Drew do it?

[Flatlandman]

Your missing the point of that post. Im not trying to defend or stir the pot just posting thoughts on the tests parameters.
XPS said them selfs that a sudden interruption wont cause a jump but that seems to be all the tests are doing that i have seen. The tests should include more ways of intermittent interruption since the purpose is to make it hop. When many many ways have been tried to make the elusive frequency jump happen and no one gets a hop then a fair statement can be made of no hop. But the tests being done are the same 3 repeated so we have a thousand tests that are worth very little in the way of a final statement.

we need some one else to try the fasst test some more times to make it jump to confirm the one test that proved a jump.

or the final say can be we all pass the hat and get the independent tests that xps doesnt want to spring for.

[aviti]

	Quote: Originally Posted by Flatlandman
	Your missing the point of that post. Im not trying to defend or stir the pot just posting thoughts on the tests parameters. XPS said them selfs that a sudden interruption wont cause a jump but that seems to be all the tests are doing that i have seen. The tests should include more ways of intermittent interruption since the purpose is to make it hop. When many many ways have been tried to make the elusive frequency jump happen and no one gets a hop then a fair statement can be made of no hop.

My point is who cares if it CAN hop. If it doesn't hop at the point it is needed then the plane is in the ground. I don't know if it needs to hop or not but with all the controversy surrounding this deal, I'd rather not find out with my plane.