Kiwi's XPS test results are up.

[KrisW]

	Quote: Originally Posted by RichardCorby
	I sent an email to XPS tech support to see if there was validity in this set of test results. These negative posts about XPS is causing some problems at the field. People see what I am using and think it is unsafe after reading all the bad press in these forums. So I asked for clarification. Within 12 hours I received this response: We have stated before that our system uses a predictive hopping scheme. The only time our it hops is when the noise floor is rising/falling in a predicted pattern, long before any type of potential problem occurs. The idea behind this is to increase the range. Less noise = longer range. As stated repeatedly, REAL WORLD tests clearly show that when a single frequency on 2.4HGz is saturated, the entire band is also saturated. It does no good to hop when there is clearly no place to hop. However, to make the masses all warm and fuzzy, we are making a small change to the firmware that allows the system to hop during a fail-safe condition *if* there is actually an available frequency. So, people can perform their bench tests and easily see the change (and feel happy). In reality, the only time we have ever seen a case where this is needed is when a high power 2.4GHz video transmitter is being used directly next to the receiver (and is turned on after our system is turned on). You can also completely lock out a Spektrum system using two video transmitters next to their receiver. It needs to be clear that bench test conditions do NOT replicate the reality we have at our flying fields or in the air. We have traveled the country monitoring the 2.4GHz band, and there are simply no locations where a single frequency is turned on randomly, and with enough power to effect our system. Interference either occurs across the entire band and causes a problem, or does not cause a problem at all. In every case we have seen, ISM devices always co-exist, even on the exact same frequency. It is required under FCC/IC/ETSI rules to co-exist. Non-ISM devices do not have this requirement. Non-ISM devices would be video transmitters and radar. Video transmitters can only affect our system in the direct vicinity. Radar saturates the entire band, so it kills ALL 2.4GHz systems, including those that use true frequency hopping. Our system is the only system that uses bi-directional communications to immediately re-send data that is lost. All other systems require that they wait for the next frame. It is certainly possible to have many frames coincide with bad data and thus you lose complete control during this time. With our system, you don't. That's easy enough to "bench test" as well. We do have to say that our competition is doing a great job of stirring up things. We appreciate the extra attention we are getting. You are welcome to post this information to the flying giants website." And here it is - straight from the horses mouth. Do we fly airplanes or just sit around doing bench tests. For me it's in the flying that proves the system.

More pap from XPS. . .

"Keep the masses all warm and fuzzy". . If JD had any chance of EVER getting my business, he lost it with that little line right there. What a condescending, arrogant, assinine way of referring to the people who are going to be putting money in HIS pocket.

How do you do "real world" testing on something that cannot be proven on a test bench?? You CAN'T put an oscilliscope on a plane and fly it and observe the results, can you? Whose "Real world" results are we talking about" a Cell Phone manufacturer???

Quote: For me it's in the flying that proves the system

It's also the CRASHING that disproves the system. One crash of one of MY planes, because YOUR radio system lost link when you said it would not, is enough to have me at your doorstep demanding your head.




After remarks like this from JD, I can see NO reason to even try to give him the benefit of the doubt any more. As for not being able to get onto the FG site. . . perhaps his fingers have a problem typing out www.flyinggiants.com. Perhaps he should book mark it instead of trying to type it.

Does he think we are stupid??? What an arrogant Ba$&*(#. . .

[Kiwi]

Guys lets not be the judge and executioner at the same time here.

I will try to answer some of the questions you have raised.

The test was only intended to try and make XPS hop. I was not interested if it went into fail safe or retained some semblance of control etc etc.

I raised the noise floor slowly using several different devices. Common wireless router, 2.4GHZ video transmitter, 2.4GHZ transmitting device that allows me to send pulses, continous, and frequency hopping across the entire spectrum. That is I can set the device up to send 10 or 20 second bursts on Ch 1 to Ch13 at will.

My tests never ever swamped the entire 2.4 Ghz band width. The signal generation devices I used left at least 9 channels always open and free from interference. In other words if XPS had wanted to move there was plenty of free airspace available to it. FASST was happily sharing that airspace and the next set of tests will have a spektrum system running along side. That will be six different RC devices all being asked to play fair in a noisy environment with random frequency generation over the top to mix it all up.

I am not at all bashing XPS, its a system and it works. Its a single channel locked frequency RC device that is supposed to be superior to a 72Mhz single channel system. Thats all I have to say about it. Its your choice how you want to interpret what I tried to demonstrate as opposed to what XPS says.

All I ask is if it hops and has some secure way of avoiding interference on a SINGLE FREQUENCY then why does XPS not show us how it works. Surely the man himself could dispell all this negativity by just doing a short demo on the super secret way it is designed to hop.

If he needs a Tx module and an Rx module I am sure we can agree to send the two units I have been loaned to him and then JD can show us with the current units on the market hop and save peoples valuable models from crashing..

As for comparing XPS with SPEKTRUM or FASST thats not even a race.

SPEKTRUM at its worst is at least twice as reslient as XPS because it uses two very well spaced channels. I have tested them on the scanner but have not subjected them to a lot of noise yet. Dont worry its coming up. But two channels is 100% better than one dont you think??

As for FASST I am with XJET: I have run it on the scanner with XPS, video, noise generators etc running all around it. It uses every nook and cranny to find a place to send a signal. It certainly has never even looked like slowing down YET!!!!

As for the bench testing not being relevant and flying is the proof of the pudding!!! Well that the biggest bunch of bullsh!t I have ever heard. All the devices and testing I done were with devices you will find at any big RC event except for the signal generator. That stays hidden at the field and never ever used. However with SPEKTRUM and FASST it would be safe to use as it only ever generates a signal on one single WI-FI frequency.

As XPS state: if someone turns on a WI-FI video transmitter it blows XPS out of the water. Unfortunately the video guys are not following the XPS super secret rules of noise generation so XPS fails. 2.4 GHZ video is only transmitted on a single frequency. One of thirteen available. It does not blanket the ENTIRE 2.4 Ghz band. So if that video camera only uses one channel, why cant XPS find a a way off that channel to one of the other 12 clean ones. THAT IS WHAT BOTHERS ME: It s not as if those videos hog every channel and all the band width. They dont. SPEKTRUM and FASST live with them just fine.

SO WHY DOES XPS NOT HAVE THAT RESILIENCE????

Simple, because it cant change channels once its locked in.

Now if someone turned up at your field with a bank of 2.4 Ghz video cameras then its just possible that SPEKTRUM might get knocked around or knocked out but thats going to take at least two cameras working at the exact same time on the exact same frequencies as SPEKTRUM uses. The chances of that are practically nil (ZERO)

XPS takes a serious hit because it always defaults to channel one if there is no traffic in the area..

And guess what channel nearly all simple 2.4 Ghz video camers use. Channel 1. IN fact they appear to use channels 1 to 4 in all the models I have found so far.

Guys my intention here is to be contructive, not blindly defiant because of some brand loyalty. I own FUTABA, SPEKTRUM and ASSAN. I dont have an orange, red or gray shirt. I wear my FG swag to events. I really dont care about brand. I just want my models flying as safe as humanly possible with the absolute lowest possibilty of being shot down or taken out by a rotten communications link.

What I say here is only my own personal assesment and is nothing at all to do with FG or any other manufacturer. As for tthe competion doing a good job on raising the debate about XPS let me make one thing very clear here. Not one device (RC) has been given or loaned to me by a company manufacturing or marketing RC equipment. Its mine, or loaned to me by other FG members wjho want to see what all the fuss is about. They want to see XPS hop, FASST stand up to some serious noisy environments and see SPEKTRUM do the same.

And finally if XPS cant log on and watch my video that surely bemuses me. Because when they were hyping XPS all over the place for free they had no issues logging in here and posting videos and propaganda.. Maybe I need to send them the password they have obviously forgotten or conveniently lost..

I do not have the devices to totally swamp the entire 2.4 Ghz spectrum and see no real reason to go and procure such a device. As for the comment that the 2.4Ghz band witth is either totally swamped ot totally clean (XPS statement
As stated repeatedly, REAL WORLD tests clearly show that when a
single frequency on 2.4HGz is saturated, the entire band is also
saturated.)

Who ever made that statement still beleives in fairies.

[ricoalonso]

	Quote:
	We have not seen the video. We can't access the flying giants site apparently. ...

I don't know about that but... anyone can register in FG and access the video. In fact, I search 'JimDrew' in FG and I see that he is a registered user.

	Quote:
	We don't fly our planes sitting on a bench.

If that is their reasoning, then pls allow me to bend the logic a little more and ask: When we do our 'range testing' for a new installation, do we range test on the ground or while flying?

	Quote:
	As stated repeatedly, REAL WORLD tests clearly show that when a single frequency on 2.4HGz is saturated, the entire band is also saturated.

Again, that is an assumption which apparently is not always true.

Thanks,
Rico.

[adjonym]

I was soooo close to buying the XPS system, but fortunately I ran into the threads about the hopping issue. The fact that I allmost bought the system is why I feel like I can post this reply.
Being a technician the only thing I can say about the XPS company responses is "WOW". They designed a system that was supposed to hop between channels if possible. The only problem is that they have no idea on how they made it hop, or under what circumstances, or even have a clue on WHY it would hop.
(Not exact quote "We do our testing in the real world, not in the shop"end not exact quote)

Anyone with ANY knowledge about tech or science knows that a result that can not be reproduced within a controlled environment is false, PERIOD.
Statements like "We test in the field" is just wrong on so many levels. In order to design a system that will change channels if needed you NEED TO KNOW HOW YOU IMPLEMENTED THAT INTO THE SYSTEM! And if you know how you implemented it into the system, you KNOW what parameters are required to reproduce it.

From the XPS responses you can only tell that they have no idea on how it would work. If they knew, all they would have to do to make all these threads stop, is simply to tell how it works, and how to reproduce it. All they are saying is that it works in the field, but it's impossible to show it in testings(OMG). It must be based on a randomizer, and it only works when the internal camera clearly shows that you are flying, and not testing the system inside.
XPS Code
$secret_xps_factor = randomize(1 to infinity);
If ($camera_outside == true) and $sunshine == true {
$rand = randomize (1 to 16)
if ($rand == $secret_xps_factor){
jump_channel
}
}

I guess the simple explanation for them not saying HOW is that they are simply lying.
If I would have bought the XPS system(and again, i was sooo close to doing just that) I would have sued them for fraud.

Selling a system that are not doing what it claims is fraud, simple as that.


It's sad though, since I allways like it when new small companys comes up with something new, and taking the fight with the "big ones". I always want them to succeed, since it helps us as customers, both tech-wise and price-wise(competition is good).
It's sad though, when it all ends up in a hoax, and a fraud.(XPS works, no doubt about that, but it's not working AS ADVERTISED).

[ben_beyer]

I'm with Kiwi, two antennaes and frequencies are better than one. If I go back to 2.4, I will only use a Spektrum or FASST system. And that's all I will recommend to anyone.

And as far as the bench test not being valid, well, if it can't pass a test in a controlled environment, how can it pass in the real world?

The plane was what, 10 meters away? Either way it's suppossed to change and it didn't.

[gareth.ky]

How do those 2.4Ghz cameras get licensed? They are not supposed to cause interference if they can detect traffic on their channel.

At least one thing the XPS dude is saying is true. If they source of interference is near the Rx its going to be worse than if its at some other location.

Since WiFi stations are stuck on the ground it seems that our only real problem would be Radar and 2.4Ghz video in other aircraft.

[klhoard]

	Quote: Originally Posted by Kiwi
	. . .<snip>. . I do not have the devices to totally swamp the entire 2.4 Ghz spectrum and see no real reason to go and procure such a device. . . .<snip>. .

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What about the readily available cell phone jammers? I imagine that the guys who get a thrill out of shutting down strangers cell phones in public will get a bigger thrill going to fly-ins.
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[Simpleton]

	Quote: Originally Posted by klhoard
	. . What about the readily available cell phone jammers? I imagine that the guys who get a thrill out of shutting down strangers cell phones in public will get a bigger thrill going to fly-ins. . .

Since cellular phones don't operate on 2.4Ghz in the US, it shouldn't be much of a problem.

http://en.wikipedia.org/wiki/Cellular_frequencies

[xed]

	Quote: Originally Posted by zoomer260
	I find this very interesting ! It never occured to me to fly a Transmitter below 9.6 volts. I always gave it a bump with a field charger. Is this not needed ? What is the voltage that most get nervous with ?

Why risk it, its not worth it... Fly at full charge, it takes no time at all to recharge the batteries for a new flying day.

[Simpleton]

	Quote: Originally Posted by gareth.ky
	How do those 2.4Ghz cameras get licensed? They are not supposed to cause interference if they can detect traffic on their channel.

Many of them aren't. Power output of these video cameras is limited to just a few hundred milliwatts in the US, any more than that and you need an amatuer radio license. Trouble is, you can buy a much more powerful unit off Ebay, a couple of watts, and use it. Nobody checks the power output or licenses at the field, and those powerful units aren't known for having the cleanest signal. On top of that, anything operating on 2.4Ghz has to accept any interference on its frequency, that's why you need to hop (or have a secondary frequency in parallel). I'd ask to see the specs on any video system somebody shows up with, and their Ham license if over the power limit (I think it's 200 mw, but I'm not sure. A visit to reputable US-based video dealers would probably show what they'd sell to unlicensed users).

[klhoard]

	Quote: Originally Posted by Simpleton
	Since cellular phones don't operate on 2.4Ghz in the US, it shouldn't be much of a problem. http://en.wikipedia.org/wiki/Cellular_frequencies

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That's good to know, let's just hope that these guys buy the right jammers!!
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[Julez]

	Quote: Originally Posted by xed
	Why risk it, its not worth it... Fly at full charge, it takes no time at all to recharge the batteries for a new flying day.

Well, the Fasst stuff I have seen so far has a 5v regulator on it. As long as you apply at least 6V from outside, everything is ok. As the transmitter computers do not change all of a sudden just because someone put a Fasst module somewhere near it, we can be safe to assume that it is no problem to handle recharging like we did the decades before.
Meanwhile, some swiss guys got over 2.3 miles with the Fasst system.

Sorry for OT.

[Simpleton]

	Quote: Originally Posted by klhoard
	. . That's good to know, let's just hope that these guys buy the right jammers!! . .

Well, they can buy 72Mhz jammers at any hobby shop.

On the other hand, all you'd need is a 700 watt microwave oven, take the case off (or leave the door off for a nifty directional antenna), plug it into an inverter, and swamp the 2.4Ghz band.

[klhoard]

	Quote: Originally Posted by Simpleton
	Well, they can buy 72Mhz jammers at any hobby shop. On the other hand, all you'd need is a 700 watt microwave oven, take the case off (or leave the door off for a nifty directional antenna), plug it into an inverter, and swamp the 2.4Ghz band.

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Good point about the 72Mhz jammer. . . . .
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However, I think a guy would look awful suspicious showing up to the field with a mangled microwave oven and an extension cord!!!
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[cptsnoopy]

Thank you Kiwi for responding. I asked the question as it is the very basis of the hopping feature. If the XPS continues to operate normally during your tests then that would invalidate everything you have shown on your video. Since I own quite a few XPS receivers it is still the biggest question in my mind. Will the system hop if it is being interfered with to the point of degrading function if there is a clear (or usable) channel nearby?

Again, thank you for your efforts. They are most definitely pointed in the right direction.

Charlie