Kiwi's XPS test results are up.

[XJet]

	Quote: Originally Posted by tadawson
	For what it is worth, I think that all the tests that I have seen/heard/read about have been accurate and honest - both yours and the guys at Boeing. The big question is what was different that can explain the disparate results? That is what has not been documented.

You're dead right Tim.

Kiwi has fully documented his tests in terms of the parameters and equipment used so they can be reproduced by anyone who wants to -- but we've heard *nothing* about the Boeing tests that would allow anyone else to reproduce them.

So in my book, Kiwi's test have the greatest veracity.

Just as JD said "it hops", we have the guys from Boeing saying "it hops"

But just as JD refused to provide the parameters -- the guys from Boeing have been strangely silent about *how* they got it to hop.

Now disclosing the testing parameters would not expose the Boeing boys to any risk of being sanctioned by their employers (the excuse given to date for not releasing a more formal report) -- so why haven't they.

In my experience of such things, if it smells like a rat, squeaks like rat and refuses to prove it's not a rat -- then it's probably a rat.

And how did Boeing do it?

Well I'm picking they very gradually increased the noise floor (over a period of 11 seconds using a signal within +/- 15MHz of the XBeePro's center-operating frequency). If JD's claims are correct, this *would* produce hopping -- but that's a scenario indicative of flying at the extreme of range and *not* the profile of a typical 2.4GHz interference source.

So the bottom line is this:

JD said XPS would hop so as to avoid potential interference.

Kiwi (and others) tested by subjecting XPS to potential and real interference

It didn't hop.

JD lied.

So JD came back and said "the hopping was never intended to avoid interference, only to extend the range"

So JD admitted that he lied.

But we still have folks saying "Kiw's tests are invalid" and claiming "it does hop"

Unbelievable!

[3ddd]

if the legal actions are aginst jd then a class action lawsuit is next,then we will all get our money back even if jd don't like it.if he was smart he would start giving refunds now and minimize the class action payments

[jonkoppisch]

Yep, he said it again. No mistake. xps does NOT hop if you encounter interference unless it shows up VERY slowly.... So if someone suddenly turns on a device that causes interference to xps it will not hop. You will be locked out!!! It's basically 1/2 of a spektrum system, a single channel unit. NO REDUNDANCY!!!! The was said all along (as when using the live video and xps locked out and didn't hop) and debated.. Now he's finally admitting to it. I can't believe how everyone still defends it...

	Quote:
	JimDrew Xtreme Power Systems Join Date: Jun 2005 Location: Lake Havasu, AZ Posts: 4,415 The hopping is predictive in nature and increases the range of the system by moving to a cleaner frequency. A switch requires 512 frames of a rising (yet varying) noise floor that is +/-15MHz from the center frequency in use. As we have stated previously, a sudden increase in the noise floor (or frequency in use) will deliberately not change frequencies. This was not by accident as in the real world, if the frequency in use becomes fully saturated, the entire band is also saturated. Since the FCC has changed its position on Hybrid type devices, we will now be able to offer hopping on saturation, and even full time frequency hopping schemes by making just a firmware change.

http://www.rcgroups.com/forums/showthread.php?t=872879

Quite a bit different than...

	Quote:
	"Old Oct 10, 2006, 08:09 PM ... · #714 JimDrew Xtreme Power Systems ....... Quote: Originally Posted by pmackenzie I did a quick search, and didn't find an answer from Jim: Does this system channel hop? The Spektrum doesn't, so it is still vulnerable to outside interference. Pat MacKenzie Yes... but not like one might think. Our proprietary system uses intelligent frequency hopping. The aircraft always monitors outside interference, as does the transmitter. When either of them have a problem that can be solved by switching to another frequency, they will do it on the fly. Total time to scan and switch is just under 1ms. If there are no problems with the ambient noise level associated with the communication frequency, then it is not changed."

	Quote:
	"Oct 20, 2006, 02:04 AM ... · #949 JimDrew Xtreme Power Systems Site Sponsor ... .... FHSS hops across the entire band, potentially using every one of the frequencies in the 2.400-2.485GHz band. The Spektrum only uses two frequencies (which it apparently selects based on the current noise ratio at power-up). 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). I got this idea from several wireless internet cards that do the same thing in laptops when 802.11 becomes congested. As it turns out, this feature was already part of the MaxStream radio technology, so it was easy to implement. Reading more of the information linked to above, it is a bit more clear to me that MaxStream's patents likely include the frequency hopping, as this method uses the best of both worlds and helps to completely eliminate the diversity and multipathing issues."

	Quote:
	Oct 26, 2006, 07:26 PM Report This Post to a Moderator · #1213 JimDrew Xtreme Power Systems [IMG]file:///C:/DOCUME%7E1/admin/LOCALS%7E1/Temp/msohtml1/05/clip_image001.gif[/IMG] Join Date: Jun 2005 Location: Lake Havasu, AZ Posts: 4,105 Quote: Quote: Originally Posted by Mihai Also, trying the system with interference at the transmitter is for people that do not understand that the only interference that matters is at the receiver. You're right, which is why both sides are always checking relative signal strength and noise and hopping channels when a problem is determined.

	Quote:
	Nov 01, 2006, 07:02 AM · #1315 JimDrew Xtreme Power Systems [IMG]file:///C:/DOCUME%7E1/admin/LOCALS%7E1/Temp/msohtml1/07/clip_image001.gif[/IMG] Join Date: Jun 2005 Location: Lake Havasu, AZ Posts: 4,105 I have not done any testing with 2.4GHz video. I will look into that today. We have a black widow system that is suppose to be high power. I think as long as one of the 8 different frequencies are used, and it doesn't drift really bad, there should be no concerns with our system. Since we have the ability to move frequencies (unlike the Spektrum stuff), if someone turns on one of these and it makes the noise floor higher, we jump to a new frequency. As long as the power is not tens of watts, I don't think it can saturate the band enough to cause a total loss of communication where a frequency change could not occur (due to the inability to communicate and execute the frequency change). I just ordered one of these 1000mw transmitters for further testing.

[GBR2]

It's amazing how post statements can come around to bite you in the a**. But wait, everything will be perfect again with the super firmware update.

[KrisW]

	Quote: Originally Posted by jonkoppisch
	Yep, he said it again. No mistake. xps does NOT hop if you encounter interference unless it shows up VERY slowly.... So if someone suddenly turns on a device that causes interference to xps it will not hop. You will be locked out!!! It's basically 1/2 of a spektrum system, a single channel unit. NO REDUNDANCY!!!! The was said all along (as when using the live video and xps locked out and didn't hop) and debated.. Now he's finally admitting to it. I can't believe how everyone still defends it... http://www.rcgroups.com/forums/showthread.php?t=872879 Quite a bit different than...

So . .let me get this straight. . .this was all some sort of horrible "Failure to communicate" ???



(pun intended. . . )

[spoiler]

I spent some time on the weekend reading the RCG XPS forum. It seems clear that XPS is using its customers as field test guinea pigs. They even ask for their input on design. Amazing...

[jonkoppisch]

More... Remember, you can't fly xps if there's WET GRASS OR HUMIDITY!!!

	Quote: Originally Posted by ozghost1952
	Flew in good sunny weather on Saturday - 4 flights with Raptor 90 practicing for Sunday competition. Typical run up to aerobatic manoeuvres is to fly as far out, perform stall turn and then fly back and forth along the flight line doing whatever – reason for mentioning – far distance – long range. On Sunday after completing the hovering manoeuvres – switched into idle up – and on the way out – heli went into failsafe (engine and pitch went low). Fortunately came back on air and managed to turn around and come back to land. What was different – only weather conditions – low cloud cover and light mist - pretty high humidity… Did all the usual checks – range was fine – battery tested OK – aerial connection fine. What should I be looking for? Can high humidity lower the range so severely? I was the only XPS at the field – rest of pilots flew out the day with no problems Regards Jeff

	Quote: Originally Posted by HarrisM
	It's quite possible that there was some condensation on your electronics (either Tx or Rx) and this may have caused the shorter range. This can happen even more easily if you keep everything in an air-conditioned car and then take it out and use it without allowing adequate time fo equilibration. It happened to a friend of mine a while back. He was on 35 MHz then.

& the ULTIMATE ADVICE...

	Quote: Originally Posted by JimDrew
	We have people buying our systems in record numbers due to crashes with our competitor's systems. I still believe setup is the biggest factor. Getting rid of switches, regulators, and the misc. junk that we seem to believe we need is the key to reducing unexplained problems.

So remember... You can't fly xps if you're using "switches, regulators, and the misc. junk" or if there's wet grass or humidity...

People are buying in record #'s... For a good ratio example.

	Quote: Originally Posted by hcopter
	I was just reading the SEFF thread about the world record setting flight of 100 models in the air at the same time. It says there were 59 Spektrum, 3 XPS and 2 Fasst systems flying, plus 40+ 72 mhz. The only ones that had any interference problems were 72 mhz and a couple of the first generation Spektrum. Really shows that 2.4 works pretty well in general and that Spektrum has a big market share. Wonder if any of the XPS guys had their XDP running and if they came back on a different channel than they took off on.

So that's 59 spektrum, 2 fasst to 3 xps....

Is it possible that we heard more about problems with spektrum because there are 29 spektrum radios to 1 xps flying???

[seattle_helo]

	Quote:
	the ULTIMATE ADVICE... Quote: Quote: Originally Posted by JimDrew We have people buying our systems in record numbers due to crashes with our competitor's systems. I still believe setup is the biggest factor. Getting rid of switches, regulators, and the misc. junk that we seem to believe we need is the key to reducing unexplained problems. So remember... You can't fly xps if you're using "switches, regulators, and the misc. junk" or if there's wet grass or humidity...

Oh man was that a great laugh. Thanks for posting that! Very, very funny... (and sad too)

nick

[jonkoppisch]

Ah, the latest claim is out...

	Quote: Originally Posted by JimDrew
	Joe Nall, SEFF, MWE, and other mainstream events had more XPS systems than FASST systems. Spektrum definitely has a lead, but they also had two years ahead of us with market share. We are getting numerous reports (and sales) from people who are crashing the competitor's systems and switching to ours.

More xps at Joe Nall than Fasst???? I highly doubt it!!!

http://www.rcgroups.com/forums/showt...80#post9877053

How about it kiwi? Were there more xps than fasst at Joe Nall???

[GBR2]

Wow, numerous reports.

[Flyfalcons]

Why does Jim only post in forums where he can delete others' posts?

[Kiwi]

Haaa. Delusions I´m sorry to say. There is no doubt that Spektrum has the market by the short and curlies but at the Nall there was a serious amount of FASST equipment in use as well. As to what the percentages were I would not dare even guess but to say XPS outnumbered FASST would have to be a serious stretch of the imagination. I mean there were more orange and black team guys in the crowd than I cared to count and they all ran FASST.

The second flight line was predominantly FASST and SPEKTRUM. I did not see any XPS units there but then again I was not doing a survey and counting antennas either.

The other comment regarding customers swapping away from SPEKTRUM and FASST due to crashes is just downright pie in the sky BS. Quiet the reverse I would say.