Kiwi's XPS test results are up.

[XJet]

	Quote: Originally Posted by adjonym
	I'm just curious. Are there any scientific evidence that says that the whole 2.4ghz band will be saturated if one channel is saturated. JD seems to be clear about this, stating that "then the entire band WILL be saturated". I have searched everywhere for an answer to this, but I only comes up with JD's claim that this is the case.

No, this is more BS from JD.

I've done quite extensive analysis (using spectrum analyzers on the ground and in the air) and have logged many occasions when parts of the 2.4GHz band are very noisy while the rest of it is virtually clean.

JD makes this claim because the receiver module's he's using (XBeePro) have pretty poor adjacent channel/frequency rejection. They are more easily overloaded by off-channel signals than competing systems.

In effect, to an XBeePro module, the band will *appear* to be saturated by a strong signal when in fact it is not. It's because of this weakness that XPS is unable to reject a strong signal that might appear on *any* part of the band due to its lack of selectivity.

So, rather than acknowledging a weakness in the "off the shelf" modules he's using, he prefers to claim that any strong signal will saturate the band.

[Simpleton]

	Quote: Originally Posted by easytiger
	You know, I hate to say it, but I stopped reading Xjets posts. For the reasons you say. He may be 100% correct, but I know I have heard it enough from him, and, like you say, it really starts to become counterproductive. Again...even if everything he says IS right, there is such a thing as saying it too much.

Yet, amazingly enough, 100% of his posts on this board are not about XPS. There might be a clue in that.

[Boomhauer]

So easytiger, are you saying that XPS doesn't work very well?

[KrisW]

	Quote: Originally Posted by lomchevac
	So easytiger, are you saying that XPS doesn't work very well?

I'm starting to get that impression. . . .He needs to be less vague. . stand up and say it like a man. . all this mamby pamby equivocating just keeps it ambiguous. I hate ambiguity.

[Boomhauer]

Yeah whats bad is I just installed one in my 42%er a couple weeks ago and he's kinda scaring me. Hope most problems were just install problems and low voltage issues.

[jonkoppisch]

According to jd.... You should be fine as long as you don't use switches, regulators, li pos, li ions, or fly when there's any humidity, wet grass or interference, tie your wires away from the antennae & set the failsafe....

[KrisW]

	Quote: Originally Posted by jonkoppisch
	According to jd.... You should be fine as long as you don't use switches, regulators, li pos, li ions, or fly when there's any humidity, wet grass or interference, tie your wires away from the antennae & set the failsafe....

And if you don't start the engine, interference will be minimal, and you probably won't crash. . . .

[Pale Rider]

	Quote: Originally Posted by lomchevac
	Yeah whats bad is I just installed one in my 42%er a couple weeks ago and he's kinda scaring me. Hope most problems were just install problems and low voltage issues.

good luck--

[Boomhauer]

	Quote: Originally Posted by jonkoppisch
	According to jd.... You should be fine as long as you don't use switches, regulators, li pos, li ions, or fly when there's any humidity, wet grass or interference, tie your wires away from the antennae & set the failsafe....

LOL, well I did get rid of my regs, full ion power to whole system.

[Woketman]

	Quote: Originally Posted by lomchevac
	Yeah whats bad is I just installed one in my 42%er a couple weeks ago and he's kinda scaring me. Hope most problems were just install problems and low voltage issues.

Most problems were not "install problems and low voltage issues". Most problems were that XPS does not perform as we were led to believe. Rip it out and go buy FASST or Spektrum, or better yet MPX (if they ever get off their butts and offer a 2.4 system).

[jonkoppisch]

I probably had 50? flights on mine before it failed...

[GBR2]

Per Jim Drew:

"Since the FCC has changed its position on Hybrid type devices, we will now be able to offer hopping on saturation"

See, it was all the FCC's fault that it fails to hop when we think it should! What a putz.

[adjonym]

	Quote: Originally Posted by XJet
	No, this is more BS from JD. I've done quite extensive analysis (using spectrum analyzers on the ground and in the air) and have logged many occasions when parts of the 2.4GHz band are very noisy while the rest of it is virtually clean. JD makes this claim because the receiver module's he's using (XBeePro) have pretty poor adjacent channel/frequency rejection. They are more easily overloaded by off-channel signals than competing systems. In effect, to an XBeePro module, the band will *appear* to be saturated by a strong signal when in fact it is not. It's because of this weakness that XPS is unable to reject a strong signal that might appear on *any* part of the band due to its lack of selectivity. So, rather than acknowledging a weakness in the "off the shelf" modules he's using, he prefers to claim that any strong signal will saturate the band.

Thanks for the clarification.

[gregw]

It's been a few months since the promised "hopping" video that JD said he was going to produce, but so far, nothing has been shown. There is also no indication as to when the "new" firmware will be released. So, I've decided not to wait any longer. I'm moving away from XPS and have just purchased a Futaba TM-7/R607FS FASST combo for my 9CHP.

I haven't had any problems with XPS at all, but due to my lack of confidence, XPS will now be used only for foamies and park flyers.

Thanks to Kiwi for showing in a very definite and repeatable fashion, that Spektrum and FASST will fly through the interference that will cause XPS to freeze/fail-safe.

[Julez]

	Quote:
	http://www.rcgroups.com/forums/showt...73#post9905173

And another case where XPS did not work correctly, but other systems remained unaffected