Kiwi's XPS test results are up.

[chewy]

Xjet, the instructions for binding and range checking shown on that website is hilarious, isn't it? Change the frequency? Collapse the antenna? Do they know what they are talking about at all? Are you planning to buy one to review?

chewy

[XJet]

I am in dialog with the company. Apparently the information on the website is a little out of date, even the pictures are wrong. Also, with a claimed range of just 800m and no failsafe, they would be (in my book) strictly park-flier/sport-model equipment.

I've attached a picture of the latest version of this product.

[Kiwi]

Tell you what I just picked up some good stuff from them for stock. Silicone wire, heat shrink tubing. Blades for my boys electric helis. 10 sets for 38 bucks means I dont loose a lot of sleep when they get whacked up.

4mm gold connectors and a few charging leads.

I see they show out of stock on the 2.4Ghz stuff so I will wait and see there. Yes 800 meters is not very far away and it would be nice to see it full range.. I'm also sure they will get a way around the fail-safe issue just like ASSAN did with the first modules. Funny how they just picked on FUTABA for now. I wonder if they will bring out modules for the other brands.

[XJet]

	Quote: Originally Posted by Kiwi
	Funny how they just picked on FUTABA for now. I wonder if they will bring out modules for the other brands.

Yep, they say a JR version is due out shortly.

In my experience, it's always a risky proposition to by version 1.0 of anything that's made in China :-)

[Toumal]

	Quote: Originally Posted by XJet
	I am in dialog with the company. Apparently the information on the website is a little out of date, even the pictures are wrong. Also, with a claimed range of just 800m and no failsafe, they would be (in my book) strictly park-flier/sport-model equipment.

800m is plenty for normal flying, but you have a point.

Also, it can't be good for a simple reason: It doesn't have a Graupner-label. :P

[mr.sneezy]

	Quote: Originally Posted by XJet
	I am in dialog with the company. Apparently the information on the website is a little out of date, even the pictures are wrong. Also, with a claimed range of just 800m and no failsafe, they would be (in my book) strictly park-flier/sport-model equipment. I've attached a picture of the latest version of this product.

This looks to be the same product I'm involved in flying tests with here in Oz.
Could you PM me, I want to know if we're talking to the same company.
Thanks
Martin

[gully]

WOW.
Stumbled onto this thread yesterday and like a good book, I couldn't put it down. It has it all.
A bit of acceptable RF testing with video to see if a product acts or re acts as is claimed in the marketing by a manufacturer.
(Nice unbiased test Kiwi.)
It's got a heap of techno babble disputing or agreeing about how this and that works.
Some personal attacks.. biased opinions, some funny stuff and a lot of off topic bits Just to pad it out.
Excellent stuff

Here's my take on all this.
I have an Assan module in my Eclipse 7. Best thing I ever did as it fixed all the glitches with my electric helis. never had a problem with it since it went in.
Do I understand that it has no more redundancy than 36meg? Yes I do. It was never promoted or sold as anything other than what it is. (A single channel once linked 2.4 system)

Do I expect to get a hit one day and loose a model because of the no redundancy? Yes I do, You would be naive to expect otherwise. I run the same risk now in that respect as I did with 36meg. Kiwi's Assan test showed no surprises

Am I happy with it? Yes I am as it's fixed up all the other issues I had with the helis

Would I use it in an expensive or large model? Not a chance, it has it's limitations they are clearly spelt out and it's horses for courses.

XPS have or had clearly been promoting and selling their product as being able to swap channels as required to aviod signal loss. No if's... No buts... No clauses...

Kiwi's testing shows otherwise.
Thats what this whole 65 page thead has been about.

XPS will fly your chosen rig around the sky just like any of the other systems on the market. No argument there! As an RC platform good or bad it works.

What I strongly object to (and I assume it was the purpose of the thread) is that it is being marketed on the basis that it has features it clearly failed to show work in a lab test.
It is effectivly selling you on the false guarantee of a system link redundancy it does not appear to have.
That's the issue
If a business can't be up front with you as to the ability or suitability of the product they sell without refering to the fine print they should be treated with caution and seen for what they really are.

I look forward to seeing how this all turns out.

[cptsnoopy]

Hi Gully,

The best part, 65 pages of this thread helped to get XPS to improve their product. I have upgraded all of my XPS equipment and feel much better about its reliability. I am now willing to use it in my larger aircraft. So, XPS may have made some claims that have been difficult to prove but in the end (and after the upgrade) it appears to be a worthwhile system.

[Toumal]

	Quote: Originally Posted by cptsnoopy
	I have upgraded all of my XPS equipment and feel much better about its reliability. I am now willing to use it in my larger aircraft.

I *believe* you're right that V3 solves one of the two major problems (same-channel interference resilience). Both, if you add that second receiver and position it 90 degrees and at a different spot compared to the first RX.

	Quote: Originally Posted by cptsnoopy
	So, XPS may have made some claims that have been difficult to prove but in the end (and after the upgrade) it appears to be a worthwhile system.

The problem is that XPS keeps making claims that... ahem... collide with what's being taught about RF, or plain logic for that matter. Since it's clear and confirmed that without a working signal path between RX and TX, V2 does not hop, they now claim that in such scenarios hopping would not help because "there's nowhere to hop to". Their own test video only confirms my suspicion that V2 needed a "hole" in the offending carrier wave, a short time of clear reception to allow the RX to transmit the hop command back to the TX. Tests that showed XPS to remain in lockout are now claimed to have saturated the receiver front-end. No explanation was given why my 3W transmitter at a comparable distance does not swamp my R617FS. Their story regarding frontend saturation, distances to interfering transmitters, interference in general just doesn't add up.

And frankly, claiming that there is no single-channel transmitter powerful enough to cause trouble for a non-hopping 2.4GHz RC system could be described as hilarious, if it weren't potentially dangerous and big things flying at high speed we're talking about. The fact is that 2.4 is open for everyone and their toys, and any kind of reliance on the availability of *your* particular channel is a serious weakness.

Even with the availability of V3, one should consider the statements made by XPS staff. Don't blindly believe my rants, but read what they have said over time, make up your own mind, and consider whose products to chose for controlling your aircraft.

[JimDrew]

	Quote: Originally Posted by Toumal
	The problem is that XPS keeps making claims that... ahem... collide with what's being taught about RF, or plain logic for that matter. Since it's clear and confirmed that without a working signal path between RX and TX, V2 does not hop, they now claim that in such scenarios hopping would not help because "there's nowhere to hop to". Their own test video only confirms my suspicion that V2 needed a "hole" in the offending carrier wave, a short time of clear reception to allow the RX to transmit the hop command back to the TX. Tests that showed XPS to remain in lockout are now claimed to have saturated the receiver front-end. No explanation was given why my 3W transmitter at a comparable distance does not swamp my R617FS. Their story regarding frontend saturation, distances to interfering transmitters, interference in general just doesn't add up.

That's nonsense. Receiver sensitivity plays a big part in saturation. If your receiver is not very sensitive, it won't be as affected by spurious noise (but it also won't work well). The patents pending for the antenna technology used in our RF modules pertain to selectivity and sensitivity.

There is no "hole" necessary. Look at the video again. The hop occurs LONG before the noise threshold could ever affect the transmission, and clearly with HUGE amounts of noise, there are no issues anyways. What was demonstrated in our video shows that numerous devices (even those that are not spread spectrum in nature) just a few feet away don't cause a problem. We don't fly with any number of devices in close proximity. It would take substantial wattage (way more than the public can obtain) to even cause a problem, and those devices that can produce this kind of power do not operate on a single frequency, but instead wipe the entire band. That is the reality.

[Julez]

	Quote:
	The hop occurs LONG before the noise threshold could ever affect the transmission

Now this is just what Toumal wrote. If the noise is slowly ramped up, and the system has all time in the world to negoitate a hop, it might eventually do so.
But what if the noise interrupts the channel before such a negotiation is made? How do both ends of the system know if the counterpart has hopped or not?

[RocketFuel]

OK Guys, please summarise without predudice...
We have seen Kiwi's XPS results, We have seen Jim's replies... We have also seen that Graupner has adopted the system and categorically state on their web site that it does what it is claimed to do, - ... and they fanfare the new release - ... Big business... so I guess they are not fools. So regardles of operational methodology -
* Is the system as safe as FAST and Spektrum? - they both have their faults.
* Does the new software release give you confidence in the system?
* Are Graupner mistaken