Independent tests prove lack of frequency hopping with XPS

[Kiwi]

Guys.

I wont have the FASST equipment here until mid next week. It has been the hardest to pin down. The Spektrum system I should have here with me on Monday.

As for the XPS going into fail safe it does if I swamp it but it does not if I run the noise floor up all around it, pulse it etc. Hitting it hard front on does knock it over.

My thoughts on why it is doing that dont matter. My thoughts were that XPS would move away from that steadily rising noise floor even if it does not knock the system over. I thought it would look for a cleaner environment if the situation got murky for it.

Also their was ample evidence that XPS slowed down and sometimes did not respond instantly to a control input when those pulses and traverse tests were being done. I dont have any way to see how many packets were lost or what the delays were in real time. But the system got slow and jerky.

Guys I need to take some time out as work requires that I'm away for the next 6 days. One thing I want to do is set the receiver up for a shorter fail-safe reaction and I want to change the power settings on the Tx. I also want to space the Rx much further away from the Tx as they are sise by side at present and thats not a real world situation.

As for turning all the systems on together and letting them have a free for all that wont show anything. FASST, XPS and SPEKTRUM and ASSAN will all live harmoniously together with just three or four, our ten or twelve radios all working. I will try to do that but I only have one module based FUTABA radio and that runs ASSAN, FASST and XPS for me. Its kinda hard to plug all three modules in at the same time.

However guys the point of the initial test was to make XPS hop. Not to see if it went into fail-safe or see if it stood up to the test of being slammed with interference. My test was to find a way to make it hop first. Actually the whole reason for the thread in the first place.

With what I done XPS will not hop. I dont have any other devices at my disposal to clinically make it do so. If it hops in the presence of FASST then we will see it as I will test it as promised.

All the systems I have will get the same battery of tests I carried out with XPS. This is not over, its not aimed at exposing XPS as being anything its not. Hopefully it is just pure plain old facts ungarnished with opinion.

[jonkoppisch]

	Quote: Originally Posted by JimDrew
	Wires moving around the receiver is a potential cause. We have had many reports of a snap roll or other high-G manuevers inducing a failsafe condition. If servo leads are allowed to move back and forth around the receiver, this changes antenna frequency and the system can no longer "hear". Simply securing the wires in every reported case solved the issue.........

Wiring seems to be a popular excuse for loss of signal. That should be included on the next round of tests.... Seems that if the receiver is that vulnerable to wiring then the case design seems rather poor?

[jonkoppisch]

	Quote: Originally Posted by sweetpea
	Then ASSAN and several other one freq brands of 2.4 need to be banned as well.

I thought assan was for park fliers? If so, they have rated it correctly instead of making up magical spherical radiation antennae systems...

[ricoalonso]

In another thread at RCG where someone claimed or thought that they were able to make XPS hops to another channel using FASST system to emulate the noise, it don't think they experienced the XPS to lockout. What I remember is that he mentioned that there were some glitching experienced in the servos. To me, it means that XPS doesn't really have to go to lockout state before hopping, which makes sense because if the Rx can no longer communicate then it cannot tell the Tx to change frequency. So, I would think that as long as the noise is brought to a level that some packets get lost but before lockout then XPS should have 'hop' already... that is if it is really capable of doing so.

[buttface]

	Quote: Originally Posted by jonkoppisch
	I thought assan was for park fliers? If so, they have rated it correctly instead of making up magical spherical radiation antennae systems...

You can see the spherical radiation waves traveling though the air if you are wearing X-Ray vision glasses!But only if the Flux Capacitor doesn't have a broken pig tail.

[Julez]

Hi!

What sense would it make trying to hop away from an FHSS signal?
This would be like walking around on a football field trying to stay dry in the rain.

It is the eave that must be avoided.

[wrightme]

	Quote: Originally Posted by sweetpea
	Then ASSAN and several other one freq brands of 2.4 need to be banned as well.

A walk down THAT road leads to banning of ALL single channel systems! 72mhz is one radio per channel at a field, PERIOD. At least the XPS can coexist with another tx/rx set on the same channel. (Note: Do not misconstrue this, I do see the failure to hop in this test.)

[sweetpea]

	Quote: Originally Posted by wrightme
	A walk down THAT road leads to banning of ALL single channel systems! 72mhz is one radio per channel at a field, PERIOD. At least the XPS can coexist with another tx/rx set on the same channel. (Note: Do not misconstrue this, I do see the failure to hop in this test.)

That was my point. XPS was no more dangerous than any other single freq system. (now it may not be more optimum in some situations than other single freq systems but that is another point)

If the hop algorithm is truly non-exstint or non-practical than the wording in the package needs to change and maybe it shouldbe reccommended not to be used by GS/Jets.

But that will always be up to the individual flyer.

[bosshoss]

This is a great thread, the continuing pursuit of better control of our models....

Kudos, KIWI, Xjet......emotions set aside, the info is great and informative, let's hope the developers in our hobby are watching closely. Scrutiny drives perfection.

[wrightme]

	Quote: Originally Posted by sweetpea
	If the hop algorithm is truly non-exstint or non-practical than the wording in the package needs to change and maybe it shouldbe reccommended not to be used by GS/Jets. But that will always be up to the individual flyer.

Wouldn't it be more appropriate to caution it's use in environments with greater background noise in the 2.4ghz range? Or where the use of 2.4ghz video downlinks is prevalent? I do not see anything in the test results that would indicate a greater problem for larger aircraft than for smaller ones. The main difference is in the size of impact if the band (or channel) gets swamped.

[wrightme]

Kiwi,

I would encourage you to start a SEPARATE thread with your results (closed and opened for YOU to post YOUR results) so that we do not have to page through all the other comments to see the data.

[Daemon]

	Quote: Originally Posted by Kiwi
	All the systems I have will get the same battery of tests I carried out with XPS. This is not over, its not aimed at exposing XPS as being anything its not. Hopefully it is just pure plain old facts ungarnished with opinion.

The problem is, you've said repeatedly that this set of tests was designed to try to make
XPS hop. The other systems either hop all the time, or don't claim to hop at all, so running
the same battery of tests with the same intent, doesn't tell us anything we don't already know.

The intent of the tests needs to change to what I suggested, which is seeing how each
of the systems react to the noise in terms of responsiveness/lockouts/failsafe etc. I
suggested having them all on at once because they *DO* play nice together, not because
they don't. That way we know that they all are seeing the exact same Rf environment at the
same time and operating normally. When you sweep the noise across the whole spectrum
you then monitor how each system responds to it.

And BTW, the reason people keep asking you to run FASST is not so much to test
it, but to test XPS with it. There's only been one reported case of XPS hopping, and
that was with someone touching the FASST Tx antenna to the XPS Rx antenna. XPS
hopping in response to FASST is of course pointless, since FASST goes everywhere,
but if it happens it should show up on your spectrum analyzer.
Looking forward to the results of further tests.

ian