Independent tests prove lack of frequency hopping with XPS

[1bwana1]

Dustflyer,
Yes, I feel very lucky to live here. In fact, some of our best flying days are in the winter. Time is not the reason I don't build. I have no skills, and no tools. Thank God for ARFs, and used airplanes. LOL!

[eyepoker]

arizona... lake havasu area most likely.

Well, I am not an RC-er - I do have an rc helicopter though but thats not why i am posting.

For those that do not know Jim Drews history with electronics I'll walk you through it.

First, Jim Drew started making expansion boards for the Amiga Computer community. As you might realize this was some time ago. Do a google search for Jim Drew Amiga. he promised a lot and delivered little. At first the community was all a buzz with his promises. He had several interviews in Amiga magazines. Then, over time, the sour threads appeared and the doutbfull magazine articles.... i unfortunately don't know enough to tell you whether or not he shipped product, but i think its a safe bet he did while not delivering on the full set of features/performance and then I am certain that future hyped product never materialized.

Next, Jim created Wicked Air Sportz - wickedairsportz.com - and created a number of electronics boards for Paintball Markers - all based on the same code - all essentialy the same (a different pcb per marker). Yes, his boards worked, they worked pretty good. But he entered at a time when there wasn't any innovation in that area at all and so he had a great start.

he used pbnation.com to let everyone know about his products - sort of a viral thing - he didn't pay for advertsiing but made lots of claims and generated a lot of hype - none were proven... finaly he got to the point where he thought his job of "marketing" his product was complete and so he started deleting posts and threads off of the forums. He even threatened legal action if those threads he couldn't delete weren't deleted.

Well, in the end no new products materialized and the Paintball Electronics market quickly matured. He sold thousands of boards - they did work - but the competitors stuff was and is better. Again he had the luck to enter that market when the existing electronics were quite easy to trump.

Jim has fallen silent in the Paintball world for some 3+ years now. He's moved on to you guys, selling you his stuff. Everything you are experiencing is simply what Jim Drew does. He is simply repeating his business model.

Anyone can discover this... just do a search. The paintball stuff might be a little hard to find - it appears to me that he's done a good job of deleting that stuff. Or maybe not, I've not tried to look as I've seen this stuff first hand having been one of his very first customers (i preordered at a discount before commercial availability)

Anyway, best of luck to you people. I'm not a true RC'er as i said and this is just a random visit from a guy who although happy with Jim Drew's Equalizer board (for paintball) has quite a bad impression, experience and a little knowledge you might not be aware of.

[Chris F]

Thanks for going to the trouble of posting here eyepoker. It is one thing to hear from RC users, but to hear it from someone else regarding one of JD's previous products puts his business into perspective for us all. I remember searching through some of the Amiga and paint ball forums about 6 months ago and was worried to read a post that said something like, now JD has moved onto 2.4GHz systems for RC and is sprouting the same sort of hype. He has them all sucked in at the moment, I wonder how long it takes for them to realise it.

I hope XPS can be made to work as advertised, but even if it does, Australia has just received its first shipment of 6 ch Rx's that were promised by last Summer and it's almost Winter. To make matters even worse, these XPS Rx's cost almost twice as much as a Spektrum 6 ch Rx.

If eyepoker is right (which I hope he isn't) we can expect to see XPS fade from the scene in the next couple of years as other companies surge ahead with 2.4 GHz (or some other) technology.

[KrisW]

	Quote: Originally Posted by Chris F
	Thanks for going to the trouble of posting here eyepoker. It is one thing to hear from RC users, but to hear it from someone else regarding one of JD's previous products puts his business into perspective for us all. I remember searching through some of the Amiga and paint ball forums about 6 months ago and was worried to read a post that said something like, now JD has moved onto 2.4GHz systems for RC and is sprouting the same sort of hype. He has them all sucked in at the moment, I wonder how long it takes for them to realise it. I hope XPS can be made to work as advertised, but even if it does, Australia has just received its first shipment of 6 ch Rx's that were promised by last Summer and it's almost Winter. To make matters even worse, these XPS Rx's cost almost twice as much as a Spektrum 6 ch Rx. If eyepoker is right (which I hope he isn't) we can expect to see XPS fade from the scene in the next couple of years as other companies surge ahead with 2.4 GHz (or some other) technology.

Personally, I hope he IS correct, and XPS fades into nothingness. . nothing personal against the buyers of the product, but people like JD make it very hard for people in this hobby to accept true innovation and technology improvements.

[USN_POPS]

	Quote: Originally Posted by KrisW
	Personally, I hope he IS correct, and XPS fades into nothingness. . nothing personal against the buyers of the product, but people like JD make it very hard for people in this hobby to accept true innovation and technology improvements.

I was around when the likes of Phil Kraft, Carl Goldberg and many others were the true inovators of the RC world.
Over the years, their ilk have passed on, and the hobby has gone to be more corporative in nature with large companies dominating the market, and developing the new products, and the new technologies.
In November 2006, I ran across the XPS website, and thought now here was a new inovator in the hobby. The ideas and data presented were right up there with the ideas of the Phil Krafts of the 50's and 60's. Inovative, and the little guy perhaps outdoing the big corporations.
Right then I decided that XPS was going to be the cream of the crop in 2.4, so decided against the DX-7 for Xmas and kept going to the XPS website daily looking to buy a system. Finally - April 2007, got to order. And used it for a year quite successfully. But more and more it was becoming evident that XPS was not to be the Phil Kraft or Carl Goldberg emulation of this century. But perhaps a flash in the pan, and in a short time, no longer there.
So I now am using a system from a Corporation, and it's working just as well, and at least the corporation will be there a year from now. And if what has been said in these forums is fact, I may actually be safer than I was before. Only time will tell.

[hillmanr2]

Here is a sobering thought that I hope does not come true. If xps made false advertising claims that can be proven through independent testing, and someone installed an xps system based on that advertising information, and followed installation recommendations, a very scary and potentially, painful liability issue exists. We all know insurance companies will not pay out unless they have a scapegoat. If someone becomes injured or worse (I truly hope this never ever happens) by a plane using an XPS system, installed correctly, XPS would be liable and on the hook for potentially tens or hundreds of millions. Even if XPS is setup as a limited liability company JD would still be responsible because he knowingly put out a faulty product. It could, perhaps would, even be made into a criminal trial. God help him if the accident is fatal. This would cross the line to manslaughter.
Worse yet anyone participating in this thread still using an XPS system now that "some data" has been provided could become liable if they are using a system that is knowingly potentially questionable.
I usually stick my finger up at people who talk about law suits, but this time I know it is different.

I have never owned bought or tried anything JD or XPS has ever manufactured or distributed. I do not know him,XPS, or anyone working directly or indirectly. I do not know anyone using any of his products or systems.
Just so we are clear

[KrisW]

	Quote: Originally Posted by hillmanr2
	Here is a sobering thought that I hope does not come true. If xps made false advertising claims that can be proven through independent testing, and someone installed an xps system based on that advertising information, and followed installation recommendations, a very scary and potentially, painful liability issue exists. We all know insurance companies will not pay out unless they have a scapegoat. If someone becomes injured or worse (I truly hope this never ever happens) by a plane using an XPS system, installed correctly, XPS would be liable and on the hook for potentially tens or hundreds of millions. Even if XPS is setup as a limited liability company JD would still be responsible because he knowingly put out a faulty product. It could, perhaps would, even be made into a criminal trial. God help him if the accident is fatal. This would cross the line to manslaughter. Worse yet anyone participating in this thread still using an XPS system now that "some data" has been provided could become liable if they are using a system that is knowingly potentially questionable. I usually stick my finger up at people who talk about law suits, but this time I know it is different. I have never owned bought or tried anything JD or XPS has ever manufactured or distributed. I do not know him,XPS, or anyone working directly or indirectly. I do not know anyone using any of his products or systems. Just so we are clear

This has been mentioned in several places throughout this thread, but it never hurts to reiterate it. JD is liable, no matter if he wants to be or not. No one wants to see anyone hurt, but the hurting on peoples wallets is going to start getting outrageous if these failures continue.

[skubacb]

Here is a sobering thought.

Nowhere have a read about or heard about, anyone that can cause a repeatable or testable XPS system failure.

I am not saying that there might not be one but going off and calling people liars and talking about law suits without a drop of proof is lame, boring and irresponsible.

Kiwi's "test" only showed that you can saturate the XPS system. It did NOT show that XPS will not hop. Time and time again it has been explained that it takes a specific environment to make XPS hop. A pure saturation of the 2.4 band is apparently it not it.

If you want to sue someone how about Futaba "We get it right the first time". Two known, proven, and repeatble failures. Zero UID and heat problems.

Or Spectrum, Park Flyer v1, full down elevator, v1.2 I don't know but they now have v1.6 out. Delinking in the air. This has happened to their own pilots.

It is crude and less than child like behavior to call someone a liar without proof. The internet is a great place but the idea that you can post postulation and speculation as fact is irresponsible. Come up with a repeatable test that proves something.

[BaldEagel]

skubacb

You obviously have only just come onto this thread without reading through it, otherwise you would have read my posts when I consistantly got lock outs on my system in the same places on my flying field as I did in the air, this was repeated with four different Rx's and two different Tx modules, the Rx's stayed locked out until moved out of the area of interferance, this was a real life test no fancy equipment, just a real test of the system in a real environment, in a RC plane on a field that uses Spektrum and FASST and 35Mhz PCM without problems.

Mike

[skubacb]

BaldEagel: Repeatable means that other people can repeat the same error around the country. I.E. a system fault.

I have around 2000 flights with XPS and have not experienced that problem. I believe you when you say you had the problem but it may have been just that environment. The XPS's reception seems to be a little more sensitive than the other systems. Since no one will fly out to 5 miles, I wonder if they should detune it some?

Of the people that have had problems I just can't see a repeatable link. It seems more random vice the Spectrum and FASST problems. Although, some FASST owners have the heat problem and some don't. Doesn't seem to be a single RX problem. At least XPS will talk with you. Futaba knows about the problem. They have one memo and basically are going to make everyone wait until this fall for some sort of answer.

[Toumal]

	Quote: Originally Posted by skubacb
	Here is a sobering thought. Nowhere have a read about or heard about, anyone that can cause a repeatable or testable XPS system failure. I am not saying that there might not be one but going off and calling people liars and talking about law suits without a drop of proof is lame, boring and irresponsible. Kiwi's "test" only showed that you can saturate the XPS system. It did NOT show that XPS will not hop. Time and time again it has been explained that it takes a specific environment to make XPS hop. A pure saturation of the 2.4 band is apparently it not it.

First of all: Thread resurrection.

Second of all: Kiwi's video was about interference, not saturation. There's a fundamental difference between these two.

Third of all: It is a fact that JD's "spherical antenna" has a blind spot, as does any other single ground-plane monopole design. There's nothing to debate about, this is how it is and every single piece of technical teaching and writing on the subject says the same thing. The antenna characteristics are well known and not up for debate, unless JD produces evidence of the contrary. Remember, it's JD who claims to have invented a magical antenna. It's always up to the guy who claims something to prove it.

Fourth: Kiwi's test is repeatable and rather well documented. JD, in his attempt to "debunk" Kiwi's test, fundamentally altered the test setup - he put the RX right up against the interfering transmitter, thus indeed saturating it. Well, except his own receiver, which he helpfully kept at a few more inches distance which, as you learn when you study this stuff, is a significant factor because the power falls by distance squared. And oh, JD did prove one thing: That his system didn't hop away from the interference.

Fifth: You having fown x amounts of hours without problems doesn't "disprove" fundamental design issues, like having the receiver request a channel hop from the transmitter. It's rather logical to conclude that this means trouble if someone just flicks a switch on their interfering 2.4 equipment, and Kiwi's test plausibly confirmed that. Doesn't matter if you fly 10 years without problems, tomorrow someone like me will switch on their 2.4GHz FPV system nearby while you're flying, and you will lose your aircraft, while the FASST and Spektrum guys stay in the air.


It's not about random and hard-to-grasp problems. It's really rather simple: XPS doesn't hop when there's an interfering signal on your channel that appears instantly, and the single antenna design has a blind spot that can cause loss of control under adverse circumstances. No system is perfect, but XPS is technically inferior.


Fly with it, it's your choice and your responsibility. But don't claim that the problems don't actually exist or that we're making this stuff up. And please, read the thread you're replying in before you write your answer. Thanks.

[ricoalonso]

second on that thread resurrection. I thought XPS finally released the long promised hopping video.

Anyway, as I asked in my deleted post in the XPS forum: Why did JD even wasted his time debunking Kiwi's test and even took him months to do it and yet not show that XPS will really hop? Publishing the hopping video (which he promised) showing that XPS will hop 'using the same parameters/criteria which he published himself' is the best way to debunk anyone's test or notion that XPS doesn't hop. So, why didn't he do that?

Thanks,
Rico.

[GBR2]

Probably because he has to work on all those other 30 or was it 61 new products that are going to be released by the end of the year. He has backtracked so often on what he has said, does it really matter if he produces a hopping video or not? According to everything I've read, the conditions to produce such a hop are so very specific as to be useless. So hopefully instead of wasting time on a hopping video one would hope he is spending sometime to rewrite the firmware code so his system does what he originally said it would do. Assuming that it is possible to do with the current hardware.

[ricoalonso]

Yes, I agree. Instead of wasting time to prove or debunk any test on the hopping ability of the current firmware, I think JD should concentrate more on the new capabilities and telemetry. It just surprised me that after the issue seemed to have been forgotten (or quited down) that some would dig it up again. But JD seemed to promise this capability in his new firmware (I think) as mentioned in a new thread (http://www.rcgroups.com/forums/showthread.php?t=889115) in his own forum and stated partly like:

"Obviously, we can make the system change frequencies whenever we want to. We know that exact method to use for bench testing. That method came from an accumulation of real world testing. That ability has now been improved by moving to a clear frequency when you instantly saturate the frequency... even though this will never occur in the real world. It may make the bench testers feel better, and perhaps give confidence to those that believe bench testing results are the same as real world testing results."

Anyway, hopping or not in the current firmware version is no longer relevant, IMO. Maybe XJet should have close this thread already.

Thanks,
Rico.

[BaldEagel]

Notwithstanding any of the above, my real world situation proved to me that the XPS system did not hop to another frequency, just locked out and gave me four brown trouser moments during the flight.

Closing the thread would not serve any usefull purpose other than stopping others who have an interest in not finding out that there is a possible problem with these units in some situations.

As I have said the area I fly in has no problem with Spektrum or FASST or PCM radio, it does have a consistant problem with PPM, but I am not saying that it is PPM interferance that is causing this problem, mearly that within the areas concerned some kind of interferance exists. To reitreate the areas concerned are in direct line with four long range communication towers on either side of a river estuary, these towers are not in sight, but have been plotted on an Ordance Survey map.

Mike

Mike