Kiwi's XPS test results are up.

[KrisW]

	Quote: Originally Posted by XJet
	In the meantime, we should wait for the rest of the test results to come in and avoid re-hashing long fought battles which really constitute little more than an irresistible force versus an immovable object.

With enough irresistible force, immovable objects break and disintegrate. . . . you can always make more irresistible force. . immovable objects are finite and cannot be rebuilt.

Zen 101

[Flyfast1]

	Quote: Originally Posted by XJet
	As others have stated, I think it's important that this thread remains objective. Those who have "faith" in XPS will never be swayed by any arguments put here so it's probably best we don't bother trying to mount cases for or against -- simply look at the data that's presented and draw your own conclusions. I'll be posting a URL shortly for an article in which I hope to wrap up the XPS situation (again in an objective but "no punches pulled" manner) so that there will be a place on the web that those looking for informed information and opinion can go to find it -- without all the fanboys versus naysayers "noise" that has accompanied the presentation of such information to date. In the meantime, we should wait for the rest of the test results to come in and avoid re-hashing long fought battles which really constitute little more than an irresistible force versus an immovable object.

Xjet,

If you are going to write an article on the XPS system, I'd like to see a discussion of the benefits of the bidirectional communications between the transmitter and receiver (other than the telemetry aspect). I don't think any of the other systems have this feature and I think it does provide some benefits. For example, my understanding is that in situations where interference is short in duration, the transmitter system will retransmit data until the receiver acknowledges receipt of uncorrupted data. This may happen many times before the next frame, while other systems would have to wait for the next frame to transmit again. If the interference is continuous on the channel that an XPS system is currently using, then it would not appear to provide much benefit, but in real world applications I don't know how common this type of interference is (other than for example a wireless camera on board the aircraft and transmitting continuously). I don't see this aspect of the XPS system discussed much and I think it would be helpful for us to understand.

-Ed B.

[KrisW]

Just out of curiosity, and since I can't get the answers I want very easily, I called Horizon Tech and asked the power output of the Spektrum systems. 120mw ws the answer, with 100mw for European versions. I also asked about the FCC rule concerning non-agile transmitters that locked onto a fixed frequency, and their allowance for 1 watt of TX power, and was told that Spektrum does not fall under that section of the FCC Guidelines.

Oh well. . it would really be nice to have 500+ mw on hand. . kind of dare people to try to shoot me down with their silly microwave ovens and cell phone jammers. . . . we're just not allowed.

[easytiger]

	Quote: Originally Posted by madmax
	Gents, First off, I want to welcome all of the new members who have come out of the woodwork, and have brought value to this discussion. Welcome to FG! Also, one of our former lurkers hit the nail on the head. This thread is about non-biased testing, not all out bashing. Let's keep the topic exactally to that point, else staff will get on the nuke button. There is some awesome information here for all of us to learn from, let's keep this on point. Glad to see you all coming in to contribute and thanks again fellas! MD

It's your baby, I'm not second-guessing you, but let me throw my last three cents in...

I don't want to get into another back-and-forth thing about XPS...to me, the data is already in. There is really nothing left to dispute...there are some very serious issues with the system that make it very unsafe for anything but park flyers. People are going to keep losing airplanes, and it's possible that someone gets hurt. That is the bottom line, and I think the only thing really worth saying at this point.
Notice I did not get into the Jim Drew bashing thing, that's all been said and done.

I want to cite for you a very real example of why I am so concerned:
Last year, a German fellow was paid to go to Hungary and demonstrate a large Pitts Special aerobat before a big crowd at a show. He flew on 35mhz. 35 is a model airplane frequency in Germany. It's not a model airplane frequency in Hungary. He flew a foamy around the day before, and according to the story, got some hits, but he flew the next day anyway with this large model. It went into the crowd, and killed two people, and injured two more. Dead. Two people. Because the guy chose to fly on a frequency that was not reserved for models in that country.

Now...when you fly something on 2.4mhz, a frequency that is not reserved for models here in the USA, but actually in widespread use for millions of devices(including the wireless router that I am using at this very moment), and you use something that operates on a single 2.4 frequency, with no ability to hop in the event of interference, what are you going to say if someone switches on one of those millions of devices, your plane goes out of control, and you hurt someone?

XPS is an accident waiting to happen, nothing less than that. If you need to ban me from this site for saying what I think the real issue is, so be it. I'm not going to keep posting about XPS, and I'm not angry, but I think there is an elephant in the room that everybody keeps avoiding, and if that elephant lands on someone, it might affect us all.

I wish you all the best of luck, and happy flying.

[cptsnoopy]

I fly both XPS and Spectrum. Other systems were not available when I started with these two. The XPS is because they make a drop in module for the evo-12 which I really like. The DX-7 works very well for my heli's (all 4 of the flying ones.)

I have had zero issues with XPS and only one loss with Spectrum which was caused (we believe) from a bad bearing and metal on metal rubbing from the motor. So really the two systems have been great so far. Much better than 72mhz.

I am very interested to see the test results of all the systems. It is always better to know your limitations so you can be reasonably assured that you will be successful. To say that any one of these systems is outright dangerous is quite obviously stupid as they all have improved our hobby. (that one is for easytiger).

I do agree that anytime we put a system in a high dollar aircraft we (the owner of the aircraft and radio system) are taking responsibility for what happens next. I hope all who read these test results will consider that when they choose their radio system for flying R/C.

I am now waiting respectfully for more test results.

Cheers,
Charlie

[easytiger]

	Quote: Originally Posted by cptsnoopy
	I fly both XPS and Spectrum. Other systems were not available when I started with these two. The XPS is because they make a drop in module for the evo-12 which I really like. The DX-7 works very well for my heli's (all 4 of the flying ones.) I have had zero issues with XPS and only one loss with Spectrum which was caused (we believe) from a bad bearing and metal on metal rubbing from the motor. So really the two systems have been great so far. Much better than 72mhz. I am very interested to see the test results of all the systems. It is always better to know your limitations so you can be reasonably assured that you will be successful. To say that any one of these systems is outright dangerous is quite obviously stupid as they all have improved our hobby. (that one is for easytiger). I do agree that anytime we put a system in a high dollar aircraft we (the owner of the aircraft and radio system) are taking responsibility for what happens next. I hope all who read these test results will consider that when they choose their radio system for flying R/C. I am now waiting respectfully for more test results. Cheers, Charlie

"I am very interested to see the test results of all the systems. It is always better to know your limitations so you can be reasonably assured that you will be successful. To say that any one of these systems is outright dangerous is quite obviously stupid as they all have improved our hobby. (that one is for easytiger)"

Thanks for calling me "obviously stupid".

Let me restate it:
XPS is, indeed, DANGEROUS. Nor has it "improved our hobby", in any way I can see. If it was advertised as what it is, about the same as the Assan park flyer system, who would care? But it's not. It's DANGEROUS to put this thing in your jet or giant scaler. DANGEROUS. Nothing less.

[gareth.ky]

	Quote: Originally Posted by KrisW
	Just out of curiosity, and since I can't get the answers I want very easily, I called Horizon Tech and asked the power output of the Spektrum systems. 120mw ws the answer, with 100mw for European versions. I also asked about the FCC rule concerning non-agile transmitters that locked onto a fixed frequency, and their allowance for 1 watt of TX power, and was told that Spektrum does not fall under that section of the FCC Guidelines. Oh well. . it would really be nice to have 500+ mw on hand. . kind of dare people to try to shoot me down with their silly microwave ovens and cell phone jammers. . . . we're just not allowed.

[Sired by Fire]

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cptsnoopy you may have missed this part when you signed up... just a fyi
welcome aboard

[KrisW]

[quote=easytiger;411311
Thanks for calling me "obviously stupid".

Let me restate it:
XPS is, indeed, DANGEROUS. Nor has it "improved our hobby", in any way I can see. If it was advertised as what it is, about the same as the Assan park flyer system, who would care? But it's not. It's DANGEROUS to put this thing in your jet or giant scaler. DANGEROUS. Nothing less.[/quote]


O

Okay, Easytiger. . ENOUGH!!!!!



I'm getting tired of you beating this horse. . cease and desist!!!

[gareth.ky]

Lets not get go decrying the product like that. Its sill less dangerous than 72Mhz. You can't start one XPS system on the same channel as another XPS system. You cannot shoot someone down with it. It will performs at least as will as a 72Mhz radio for interference rejection. I would take a whole field of XPS users over 72Mhz.

Are the other system possibly better? Sure. But I want proof of that.

Are their potentially dangerous failure modes in the other systems? Sure. Lets find out what they are!

[easytiger]

	Quote: Originally Posted by gareth.ky
	Lets not get go decrying the product like that. Its sill less dangerous than 72Mhz. You can't start one XPS system on the same channel as another XPS system. You cannot shoot someone down with it. It will performs at least as will as a 72Mhz radio for interference rejection. I would take a whole field of XPS users over 72Mhz. Are the other system possibly better? Sure. But I want proof of that. Are their potentially dangerous failure modes in the other systems? Sure. Lets find out what they are!

You aren't hearing me.

The only stuff on our 72mhz frequencies are other model airplane transmitters.

And there are, literally, MILLIONS of devices broadcasting on the same 2.4 frequencies XPS is using. And once one turns on to the same channel as you are using on XPS, your goose is cooked. There is no second channel, there is no frequency hopping...there is only an out of control airplane.

It's very tiresome to hear the same old argument: "oh, but the other systems have problems, too!"
They may or may not, but they don't have the intrinsic design flaw that XPS has. And "the other kids are all doing it too!" does not really cut it as a defense...

If you are saying "you'd rather have a field full of XPS users than 72mhz users", then I feel like the basic issues at the heart of this system, and the basic point of the tests done on this thread, have been missed by you. No offense intended. There is a bottom line here that was discovered...that if someone else switches on something on the part of 2.4 you are using, it can swamp XPS, and XPS is not going to switch channels, it has no defense. And there are countless devices on 2.4 that are free and legal to operate on the same frequencies as XPS does.

[wrightme]

Kiwi,

Thank you for your objective testing so far. As much as I would have liked to see you get XPS to hop, I sure appreciate all of the attention you have put in to your testing. I am also looking forward to your future testing of the other systems that you have available.