Independent tests prove lack of frequency hopping with XPS

[1bwana1]

Very good information Kiwi. Thanks for all of your efforts, you have done the RC community a service.

[sweetpea]

Thanks---glad the results were as predicted

[ricoalonso]

Kiwi,
Thanks for sharing the result. Very Good informations.

Edit: I just noticed... it went into 'lockout' instead of failsafe? Now that's even getting worst. First the 'hopping' is proven not working... now, even the failsafe is no use?

^R^

[XJet]

It seems a if those who were labeled as "no-nothing, self-appointed experts" were right (yet again).

However, I have strong doubts that even this evidence will shake the faith of those who still believe everything that XPS tells them.

Still, for the rest of the world, who have the ability to judge issues on the facts, the results are proof that XPS is indeed a perfectly adequate second-tier 2.4GHz system which works slightly better than a budget Chinese 2.4GHz set (Assan) costing a fraction the price.

[ASSAN]

TO:KIWI

Dear kiwi, thanks for your test report.

one information i need meation that is we have been update the version since 1th,Feb 2008.

i hope you can use our new version to test it again.

in my test in lab, if the powerful noise(such as 500mw 2.4G video Tx )nearby our Rx (10cm) and worked in the same ch.the control range will shorted to about 20 meters.

but it's has been improved more than your test samples'.

thank you.

meng

[buttface]

Kiwi, You are the man!
Your test results for XPS mimic what happened to me in my 40% Extra.
My ignition had developed a bad coil in flight causing the XPS to go into lock out.The surfaces froze in position extreme 3D throws (Fail safe did not come on)The plane was heading for a busy housing development as the wind carried it while falling.
I recovered the plane after it fell 200 ft. (good thing it was up high setting up for a blender.The surfaces kept freezing up as I glided in to the runway.I am glad no one got hurt or killed.

[Four Stroker]

Well buttface, that can't possibly be true. Paul Beard assured us that 2.4 GHz is well above any noise that you could get from your ignition.

[buttface]

	Quote: Originally Posted by Four Stroker
	Well buttface, that can't possibly be true. Paul Beard assured us that 2.4 GHz is well above any noise that you could get from your ignition.

It is true.DA confirmed the ignition had a bad coil.The XPS worked great for the 50 flights before the ignition went bad and the motor started misfiring.XPS simply could not hop past the noise.
You shouldn't believe everything Paul Beard says.Shame on YOU!

[JimC-MD]

Generated RF noise from ignition components is not the same animal as transient voltage spikes. A bad coil could have been firing externally. You have no idea where that would go. All it would take is one wire or component close enough to the ignition module or even the shielded wires to cause an issue. The bad could could have been firing to the case and therefore "Charging" the webbing on the outside of the ignition cables. Any radio would be whacked by that.

The thing to remember is to keep ALL ignition components separated from any gear hooked directly to the radio. I would suggest at least two inches. The reason for that would be to eliminate any chance of an actual spark jumping to a radio component and then traveling to the radio.

The material that components are mounted to should be an issue as well. Light ply would not be an issue. Some of the "bling" materials like CF or the aluminum look composite materials could make it the same as wrapping them all together.

So, ButtFace. You guys are both correct. The "noise" that is related to normal ignition operation is not of a frequency level that would effect reception of a signal. Take one of your spark plug wires and tape it to your RX and watch it dance. See the difference?

[Kiwi]

Meng,

Nice to see you guys are watching what we are doing.

For those of you who made comments about the manufacturers not taking part in our discussions let me introduce you to the sales and marketing manager for ASSAN.

Meng I will be in touch with you today regarding your upgraded units as I have some ideas also that may be of interest to you and your team.

Gents something I want to make very certain that everyone understands here is I have no fight or loyalty to anyone. None of the manufacturers gave me anything, the guys who sell the scanners and airhorn donated those devices and I am eternally grateful to them for that.

ASSAN, XPS, FASST, SPEKTRUM and the many more to come all work as RC guidance devices. Some seem to have the ability to do more tan others. Some are low priced and some are expensive.

Take the ASSAN units for example. They are a simple single channel system with pairing and failsafe capabilities. They dont hop, they cannot yet I fly my small electric heli with these systems and they perform well. I fly the heli in remote locations like my back yard or the workshop. I have never had a hit or a problem. The price is right for my small stuff and if I loose it thats my problem. I know what I have and I have no great expectations from it. I wont use it in anything bigger than a foamy or a small 450 sized heli. Thats my choice.

FASST and SPEKTRUM appear t live up to what they are sold as and they seem to do that very sell. They are robust, have an ability to skirt noise or have a secondary channel if one gets buried. I have not been able to knock either of them over. I fly the FASST system in my EF 300 electric and have flown it vertically out of sight, it has never ever caused as much as a glitch. Thats not at all saying that FASST still does not have some issues to contend with as you can see in some other threads. But on the whole it does what they say. (Issues I refer to as non compatible servos etc)

XPS is supposed to hop to a clear channel with a steadily rising noise floor, it has a hundred bells and whistles and many of them are good so dont get me wrong. But XPS is the easiest system to make fail along with ASSAN. The difference to me as a hobby person is ASSAN dont claim to be able to get out of the noise. XPS claim to hop and dodge that noisy environment. If it done just that then I am sure XPS would be first tier system, but until it can do what it claims and that these claims can be clearly and repeatably proven then its a lower quality alternative. But it is an alternative and thats the buyers choice.

Working on videos today guys so hope to have some up later tonight.

	Quote: Originally Posted by ASSAN
	TO:KIWI Dear kiwi, thanks for your test report. one information i need meation that is we have been update the version since 1th,Feb 2008. i hope you can use our new version to test it again. in my test in lab, if the powerful noise(such as 500mw 2.4G video Tx )nearby our Rx (10cm) and worked in the same ch.the control range will shorted to about 20 meters. but it's has been improved more than your test samples'. thank you. meng

[Reckless Loony]

	Quote: Originally Posted by Kiwi
	XPS base line test. ( I needed something to set a goal) OK first off I set the fail safe on the XPS so I could see it react as opposed to last time just waiting for it to fail. This time running just the XPS with the airhorn sending 5 seconds bursts over the 11 WiFi channels XPS went straight into lockout, it did not failsafe. It just froze up until the scanner had moved at least three channels away from the selected channel then it came back to life again. Pretty much what happened last time but just a little more conclusive.

And this thread proves the coma state happens in the real world and not just on the bench.

[Gordito Volador]

Kiwi,

Thanks for all of your efforts. Now we have a benchmark to see which systems will work for us based upon what we are flying and where it fits into our budget. Oh, I almost forgot, and how much money we want to risk in the air.

Regards, Bill

[KrisW]

Well. . I'm very glad Kiwi gave Spektrum such a rousing thumbs up in his report. My two FREE receivers from Spektrum arrived today, less than 3 weeks after mailing off the voucher to Horizon. So, now I have enough receivers to install 2.4 in all my planes I am currently flying, including a dual receiver setup in my ULW Comp-Arf Extra.

Now, if the TX module will just stay alive, I'll be able to get soem flying in later this week. . .

[Kiwi]

OK

I done some more testing today as I am slowly finding the things that cause an effect and those that dont.

What I found is you can seemingly jam XPS with just the right amount of interference. It wont go into fail safe but you dont have any control. If you pump up the noise then it goes all the way into fail safe as designed. Its a touchy thing to get right and involves shielding the antenna with your body or moving it behind the source of noise your generating.

Just to be sure I was not in error with the tests I went all the way back through the optional setups on the Rx again to be sure I had the country correctly selected and the power set to level 5.

I reset the fail safe to last position hold on all channels except 3 which I am using for the tests to show when the signal is lost.

I find the receiver quiet a complex little device and have to take my hat off to the guys that designed it. I mean if it really did hop away from bad interference this thing has some serious ability built into it.

For those patiently waiting for the video it wont be tonight and I will explain why. I use a new SONY HDD camera. No tape thingy, its all solid state. Well there is no editing software for this darned stuff that really works. For my MAC it looks like it will take 24 hours to render 2 gigs of raw video into a format that iMovie can use. This is in a G5 dual processor 2.30Ghz system with 16GB Ram. I cant make it any faster.

It just goes to show that even SONY produce and deliver high end equipment that has no support or decent software to create the end result I can normally do in a few hours with a conventional tape video camera.

Hang in guys, I'm not bluffing here, just screwed until this video is reformatted.

[3ddd]

kiwi thank you for all your hard work and i am sure everyone will think about this when buying a new radio.i know i will