Independent tests prove lack of frequency hopping with XPS

[sweetpea]

	Quote: Originally Posted by captaine
	Sweety, you say you met Jim Drew only once, can you tell us about that, I heard you got a free plane from him because yours crashed due to XPS failure, I believe that's an automatic disqualification for you not to post in the 2.4 threads regardless of the subject. Are you now using the XPS system and in what planes, how many flights?

Rumors are great aren't they. No I did not get a "free" plane. I did buy a replacement plane from Wild Hare though....do I need to produce the CC reciept with my name and card number on it? People believe whatever they want because I said that XPS and I came to a resolution about the my crash using XPS at the time (and no where did I say XPS had to be at fault, I was professional with them 100% of the time on the internet, on the phone and at my home). Also I didn't must meet Jim...I also met his partner, who actually did more of the talking and explaining than Jim did. I was very impressed with the knowledge of the companies product and how they treated me professionally. I still fly XPS in my smaller planes. I fly Spektrum in my larger planes.

Why you might ask? 2 reasons.

1) after my crash on 2.4 I realized that a large 35% or 42% plane had a far greater chance of blocking the signal and it has a higher initial investment from my wallet

2) I've spent 10yrs working with Radars and radio freq in the military and I understand the pencil beam vs the firehose signal that comes from 2.4 and 72mhz.

Now as to why spektrum in my large planes.......easy....satellite RX's and the data logger. Until XPS comes out with satellites and telemetry I won't use it in larger planes (I told them this when they were at my house) I wouldn't use FASST either for the same reasons and because currently they don't support JR radios either. I've found with Satellites you can compensate for the pencil beam by having multiple reception points in the aircraft. (I'm not a fan of one RX no matter how many small wires you have sticking out of it in 2.4). I like the fact I can put a RX in the tail, center and nose so I can essentially do what 72mhz did with its enourmously long antenna. Oh and I don't get shot down from a "newbie" or a slip up down the flight line (I also can't shoot someone else down!) and can look at each antenna and see the signal strength and make changes accordingly.

So, yes I can post in the 2.4 forum........what systems/experience do you have that enables you the right? Why the personal attack?


Also.......why no mention of the problems with Spektrum or FASST in this thread.

Spektrum- voltage issues, reboot times, capacitors needing glued down, trouble binding sometimes. Can anyone tell me if I send my AR9000 in that they would fix all these issues for free or replace my RX? I'd like to know. So far I haven't heard you can send in a RX for the "new" rebot time fix.

FASST- unique ID's matching 2 radios at the same time, trim changes on models
The free software is supposed to fix these that comes out on the 8th.

Of course Spektrum and Futaba are fixing their issue with updates......but nobody calls foul or B.S. And these are major issues that can and have caused crashes (in some instances). They also do a good job of pushing it under the carpet......Spektrum is calling the changes "new features" and Futaba is just submitting software updates on the website.

So XPS found from its customers 3 issues.....

small antenna did not work as well in high noise enviornments, they replaced antennas for free, and future models came with new one.

problems setting functions in the RX (too complicated for some people to cycle through) now you can get a programmer that makes it a breeze and update your software with it instead of sending in the RX

Freq did not hop in sudden high noise like customers percieved. According to XPS this was not a fault but a known solution they had to an issue of band covering interference. With the rise of 2.4 cameras being used they decided to change the hop algorithm to include sudden noise becuase of customer concerns. This may prove worse in the future, who knows. Remember this thread started as an XPS does not HOP thread. That has yet to be disproved in all instances! Xjet only proved what XPS knew from the start.

Kinda like the reboot issue with Spektrum.....I didn't see in my manual that it would take 4 seconds to reboot if power was lost. Some customer had to do that first then Spektrum acknolwedged it much later after numerous crashes/near crashes and made a customer need a fix. Sounds very familar to XPS situation




So we have 3 major stakeholder in 2.4ghz. They all 3 have had issues from day one!

But because people don't personally like JD they pick on his company or maybe because its a small company and not huge like the others or because they don't like they way he advertises or markets.
Or they just want to see the company fail. I don't know.

Fine, don't buy XPS. Nobody is pre-charging your credit card.

I agree that we need to keep the thread open.......but come on....personal attacks, and people bashing systems etc......all crap.

Keep it professional. State the facts.

That is all we, as customers need......

So I'll repeat the FACTS as stated by the manufacturers that we as customers have asked them to verify and they have by fixing their items.

XPS
-High noise, sluggish controls.....small antenna may not be for all areas (so use new antenna)
-freq hop does not happen in sudden noise rise (like 2.4 cameras)........Software fix coming
-Problems understanding how to program your RX....buy the XDP device to make it easier but it can still be done without it.

Spektrum

-battery volt issue.....buy external capictor and realize min voltage amount
-reboot time...After july 07 all RX's have a much faster reboot time (no word yet on if you can get older rx's fixed for free or at all)
-Sometimes it binds sometimes it doesn't.....no fix or cause determined yet

FASST

-Unique ID on 2 radios.....looking into this claim
-Trims change on models......should be in software fix avail 8 Jan


And if you think there won't be more problems with each of these systems or any of the "new" chinese versions.......pull your head out of the sand. There is always room for improvement. Its just with 2.4 and the software they use its much easier/cheaper to update than a PCM 72mhz RX.

[sweetpea]

So does this shake my confidence or anyone else's in 2.4? All these problems......

Sure it does. But I had less confidence in my 72mhz system. I've had planes fly great for 2yrs then develop a weird symptom that couldn't be explained from exhaustive testing. I've had lockouts, I've had crashes, I've almost turned on another persons freq (that scared me the most!). To date I have not known anyone turning on my freq while I was flying but it could have happened on one of my many early crashes and I did not know about it. I have seen it done to at least 20 people though....most of the time it made the other plane crash!

Sure 72mhz works just fine. So does 2.4ghz They both have problems, they both have risks. It all comes down to what YOU are willing to take.....the good for the bad.

I felt and still do that 2.4 with all its problems is a better system than 72mhz. And it continues to get better. Many others do not think its better. Make up your own mind.

I've been here on this thread agreeing and disagreeing with Xjet because I want truth for all those on the fence. I like what Xjet has done as far as testing. I just hope he is sitting back at home eating some chips reading this thread still. Because the majority of us on FG want him to post his data. Not to disprove what he has done, but to improve upon his test and take it a few steps further so we might all learn some other limitations or excellent features from all all the systems out there.

[Plane_Reaction]

	Quote: Originally Posted by sweetpea
	Had a long conversationg with Jim and Scott today. We went over the fields 2.4 spectrum and in detail what both pilots of my plane experienced. We talked in length what the plane did and didn't do or felt like they did and didn't do. This is much easier to explain in person than online. We also talked about the range checks both at my house and the field. We also talked about the Bennett field and his system there. He has been very busy racking his mind why my system felt sluggish. We then went to the house and inspected the plane and placement. He informed me that most test planes had the unit placed a little higher in the fuses. Not that he blamed my install but he did determine that both Vegas fields are dirty for 2.4 with alot of traffic. He plans to test my units extensivly to see what happened or if he can re-create. Jim also took "care" of me. I'm very satisfied with the results of our meeting. I look forward to XPS shipping, which he did say some units have shipped and they were headed home on Sunday to get more ready to ship!

If you did not recieve a new plane from Jim Drew could you please explain this statement. I truely believe this is where all the rumors come from. Maybe a CC Reciept would put this to bed. Sorry but I think this post is why some people think you were taken care of.

[tkilwein]

No brand war meant here.
I have the 14MZ 2.4GHz module setup and it has been working great so far with the minor trim -model issue, which I read is fixed in the forth coming SW update. Yes they ALL have issues of some sort when they are on the bleeding edge. No one is perfect in this world.

I had 2 wireless phones and 1 cell phone all on at the same time and the quick blips from the TX affecting the phones were spaced apart by some amount, the ear could separate the blips enough, so it is hopping by this crude check. The SA will show the entire profile easly. I have seen screen shots of the freq range the 14mz-2.4 occupies and it covers a wide band. The pictures are on another site and I do not have the URL. So hear say for now.

I have been testing, flying and posting results regularly here on my experiences with the 14MZ-2.4GHz setup.
http://www.helifreak.com/showthread.php?t=55670

I had the 3 phones within 2-4ft of the RX and turned them power on-off-calling, at no time did the servos glitch that I could tell visually running the built in servo tester, this is with the TX ~30ft away and in range check mode.(low power).

The bottom line I guess, is what makes the individual owner happy. That's what variety is, the spice of life.

[XJet]

	Quote: Originally Posted by sweetpea
	I fly Spektrum in my larger planes. Why you might ask? 2 reasons. 1) after my crash on 2.4 I realized that a large 35% or 42% plane had a far greater chance of blocking the signal and it has a higher initial investment from my wallet 2) I've spent 10yrs working with Radars and radio freq in the military and I understand the pencil beam vs the firehose signal that comes from 2.4 and 72mhz. Now as to why spektrum in my large planes.......easy....satellite RX's and the data logger.

Given that you believe JD to be a straight-up and credible guy can you please reconcile your statements (as someone with obvious RF experience) that you won't fly XPS in a large plane due to the blocking effect that can take place on a single-antenna -- with JD's absolute assurances that XPS does not need satellite receivers.

Right from the start I predicted that a single-antenna system was *not* going to be a good idea in a large model, even if it worked with smaller models). For my prediction, I was roundly slammed by the fanboys and JD who kept telling everyone about this mythical patent-pending spherical antenna system that nobody has ever seen (even when comparing the XPS and XBee modules side by side and posting the photos like I did).

Surely you must concede that JD is either fooling himself or trying to fool the public when it comes to the capabilities and technology involved in XPS.

If you believed what JD says (about not needing satellites and the physics-defying capabilities of that mythical antenna) then surely you would be flying XPS in your big birds to this day.

The fact that, as time rolls on, all the challenges I mounted to JDs claims appear to be proven true doesn't seem to carry any weight with the fanboys. Even the facts won't change their minds -- so why bother.

The workshop refit is still underway. If I get time when it's done, I'll perform the tests I was speaking of but I have a feeling that no matter what iron-clad, independently audited tests I presented, the fanboys would refuse to believe and call it all a conspiracy.

Fortunately, the majority of FG members (and I include Sweetpea in this list) have somewhat more open minds so I hope the results will be of value to them.

[sweetpea]

	Quote: Originally Posted by Plane_Reaction
	If you did not recieve a new plane from Jim Drew could you please explain this statement. I truely believe this is where all the rumors come from. Maybe a CC Reciept would put this to bed. Sorry but I think this post is why some people think you were taken care of.

What terms XPS and I came to are not anyone else's concerns. What we came to agreement about may not be what they do for other customers. Some they may do more some they may do less. Was I 100% satisfied? Of course not. I lost alot of money in my crash. I had over $3k invested in that plane and a year of flying on it. And I had recently recovered the plane myself. Some stuff was repairable, some was trashed and the plane was worthless except a few tail feathers. I bought a new plane because I had the money to do so. End of story.

And though many of you out there think I'm a fanboy of XPS (that term is soooo gay)...I hope you see that I criticise them as much as I do the other companies. None of these products are perfect and I expected bugs in all of them. I chose to risk my aircraft. It was not different than when I put a JR PCM RX in my 42% plane for the first time. Then switched to a JR PCM scan select then switched to Spektrum module. Each change was a risk.

I also notice that they talk more with the consumer than the bigger companies which tends to be backfiring on them.

I am not sponsored or in any companies pocket in the R/C world. Tried that back in R/C cars. Wasn't worth the hassle to be sponsored and told by the company what to say, what to run and have to perform for them. I'm in this hobby for me. I have my own job and I buy what I can afford.

If you or anyone else want to speculate they gave me a new plane, showing my CC reciept won't stop that. People like rumors. Why do you think TMZ is so popular.

[Black Sheep]

	Quote: Originally Posted by sweetpea
	So does this shake my confidence or anyone else's in 2.4? All these problems...... Sure it does. But I had less confidence in my 72mhz system. I've had planes fly great for 2yrs then develop a weird symptom that couldn't be explained from exhaustive testing. I've had lockouts, I've had crashes, I've almost turned on another persons freq (that scared me the most!). To date I have not known anyone turning on my freq while I was flying but it could have happened on one of my many early crashes and I did not know about it. I have seen it done to at least 20 people though....most of the time it made the other plane crash! Sure 72mhz works just fine. So does 2.4ghz They both have problems, they both have risks. It all comes down to what YOU are willing to take.....the good for the bad. I felt and still do that 2.4 with all its problems is a better system than 72mhz. And it continues to get better. Many others do not think its better. Make up your own mind. I've been here on this thread agreeing and disagreeing with Xjet because I want truth for all those on the fence. I like what Xjet has done as far as testing. I just hope he is sitting back at home eating some chips reading this thread still. Because the majority of us on FG want him to post his data. Not to disprove what he has done, but to improve upon his test and take it a few steps further so we might all learn some other limitations or excellent features from all all the systems out there.

My experiences almost exactly except mine was on 36 meg.
What made me think about going to 2.4 was a recent incident at an airshow I flew at and the fact that every smoke pump I used caused some interference at the extremes of the display box. I was making a knife edge pass with smoke on down the runway when a full size Jabiru flew right across my path. All of a sudden I lost radio and was heading straight for the Jabiru and then I got control back. Some say the magnetos on the Jabiru caused the problem, I don't know but it shocked the hell out of me. With many other shows to attend, I thought I have to find a cure for this and started looking at 2.4.
I nearly went for the Spektrum system but I didn't like the loose wire from the TX antenna and then I saw an ad from the distributor comparing all the 2.4 systems and I have to say that XPS stood head and shoulders above the rest. With what people are saying in this thread, it would appear there is a lot of false advertising going on here by making the claims that XPS have. I find that a little hard to swallow given the "litigation society" there in the US. It would be VERY risky for someone to claim their system does something it doesn't especially when it has the potentional of putting people's lives at risk. I don't know about the technical side of it all, I'm no techie, but I hope XJet AND Kiwi sort it out soon.
The other point is people are saying that the XPS system crashed their plane so you should stay away from it. Well, does that mean that if 72 or 36meg crashes your plane, you should stay away from it?

[sweetpea]

	Quote: Originally Posted by XJet
	Given that you believe JD to be a straight-up and credible guy can you please reconcile your statements (as someone with obvious RF experience) that you won't fly XPS in a large plane due to the blocking effect that can take place on a single-antenna -- with JD's absolute assurances that XPS does not need satellite receivers. Right from the start I predicted that a single-antenna system was *not* going to be a good idea in a large model, even if it worked with smaller models). For my prediction, I was roundly slammed by the fanboys and JD who kept telling everyone about this mythical patent-pending spherical antenna system that nobody has ever seen (even when comparing the XPS and XBee modules side by side and posting the photos like I did). Surely you must concede that JD is either fooling himself or trying to fool the public when it comes to the capabilities and technology involved in XPS. If you believed what JD says (about not needing satellites and the physics-defying capabilities of that mythical antenna) then surely you would be flying XPS in your big birds to this day. The fact that, as time rolls on, all the challenges I mounted to JDs claims appear to be proven true doesn't seem to carry any weight with the fanboys. Even the facts won't change their minds -- so why bother. The workshop refit is still underway. If I get time when it's done, I'll perform the tests I was speaking of but I have a feeling that no matter what iron-clad, independently audited tests I presented, the fanboys would refuse to believe and call it all a conspiracy. Fortunately, the majority of FG members (and I include Sweetpea in this list) have somewhat more open minds so I hope the results will be of value to them.

Ok.....lets get a few things straight........

I said the blocking effect on a single RX. Not a single antenna! I no more bought into the hype of the spherical doohickie than you. Just like I don't buy Spektrum/Fasst and having 2 antennas less than 1 inch apart calling it antenna diversity. We are stretching on all these accounts.

And I don't do what everyone else is doing out there......to me XPS is a company not a person. I've read JD's past, it didn't sound all that great but I spoke with his partner at great length at the AMA show when they first introduced XPS. I also spoke to JD. To me they were XPS not a single person. Though JD is the only one who tends to post on the internet. (had that been me, I would have made my handles XPS and left it at that....keep personal and business seperate, but that s my thinking).

Now interesting thing.......I spoke at length at the AMA show....

First----Spektrum wouldn't confirm modules were coming out. I didn't want to buy a new radio (especially a 6 or 7 ch) just to go 2.4ghz.

Next----XPS I asked alot of the questions that have already been asked here on this thread and many other threads. I asked about the freq hop and was told pretty much what has been said here. Maybe I asked the question just right or maybe XPS thought I knew what I was talking about. It is of no surprise to me the reasoning behind the decision to not have it hop. At the time I didnt' consider 2.4 cameras to be an issue either. And guess what....I asked about satellites. They said they were an option with telemetry and would come out when it did since it hooks up to that. Great I said! The 2 things I wanted from the start. RX diversity (by more than 1 inch). My question to them was can I hook 2 RX's at once....answer was no (but spektrum said you could with their system). I decided to buy XPS thinking the telemetry was about only 6 months out or so and Spektrum was a at least a year if they even did modules.

Well, I waited awhile before I put XPS in my plane. I saw several people fly XPS in smaller size planes at my field (so no need to start there for me). I also read posts by Darcy on his jet and 40% without problems. And there were several other larger scale success's at the time. I also read that FASST was coming out and it was to be a single RX design as well. So maybe I was wrong to think that only 1 RX wouldn't work and thinking that telemetry to view the signal strength and satellites was around the corner I chose to use it.


So to answer you again.......for me giant scale needs multiple RX in various locations due to the pencil beam and short antennas (FASST are not that long IMHO but better than both Spektrum and XPS for the main) 72mhz didn't need this becuase the beam was much wider and the antenna was almost the length of my plane. Thus increasing the chance of the signal being hit.

In my GS planes I use all 3 of Spektrums RX's. Basically giving me the same antenna collection that 72mhz did.

When XPS telemetry comes out with Satellites I'm sure I'll read up on the actual features and users (like I did before) and if its better than what I have or at least as good I'll pick one up. Until then my small planes use XPS where I've had no issue with blockages. And like I said.....XPS asked me if I would continue to use their system or not. I know they expected me to say no. I told them they had the best customer service, warranty and worked with the customer. I also liked where the company was taking itself with giving the customer what they wanted (XDP, software updates, endpins etc). I told them my giantscale was waiting for the satellites. (though at the time I no longer had any GS planes)



And last........thank you for recognizing I have somewhat of an open mind. I've disagreed mostly with your technique of presenting your results and some of your future conclusions off of what you found. But I'm glad you did the tests and look forward to more of yours on other systems along with Kiwi's.

[Black Sheep]

I forgot to add, since putting the system into my 35%er it has performed flawlessly and I purposefuly flew it out till it was just a dot with smoke on and the radio was as solid as a rock. I have it mounted near the floor of the plane under the front cockpit of the Extra and apart from having to try a couple of times to get a link between the TX & RX have had no dramas to date. Mind you, I fly out in the boonies in the country and haven't taken it anywhere else yet, so I hope it still holds up. Can't be any worse than 36meg. Can it?

[XJet]

	Quote: Originally Posted by sweetpea
	Ok.....lets get a few things straight........ I said the blocking effect on a single RX. Not a single antenna! I no more bought into the hype of the spherical doohickie than you. Just like I don't buy Spektrum/Fasst and having 2 antennas less than 1 inch apart calling it antenna diversity. We are stretching on all these accounts.

So (just to clarify) you also don't believe JD's claims that XPS doesn't need satellite receivers for large models?

As for diversity -- antenna diversity (such as that used by Spektrum/FASST) *does* work.

Although it won't be as effective as a satellite receiver in the case of shielding caused by large reflective/absorbent structures, it does work very well in dealing with multi-pathing and polarization issues.

In fact, fixed/close-spaced antenna diversity can (in some cases) be *more* effective than a satellite because you can ensure that the element spacing isn't an exact multiple of a wavelength and that the losses due to cross-polarization won't affect both antennas at the same time..

Antenna diversity is designed to ensure that one element is always likely to be outside of the null-point created by multi-pathing.

Futaba and FASST have the added bonus of using multiple frequencies which means that even if the antenna is nulled for one wavelength, it's unlikely to be nulled for the other(s). XPS unfortunately doesn't have these advantages and uses extra sensitivity with a positive acknowledgment protocol on the transport layer instead -- which seems to work satisfactorily.

Some claim I criticise JD at every turn -- and perhaps that's true, but only because he continues to feed gullible people with an endless stream of BS (spherical antennas, no-need for transmitter dipoles, no need for satellites, etc, etc.). Even when the evidence proves him wrong, he says that the changes he's made (dipole on the transmitter, satellite receivers, frequency hoping) aren't at all necessary -- which is just more BS.

It's important that people realize the fact that just because JD says it's so doesn't mean it's true.

Not only is the credibility of the product important but also the credibility of the company and people behind it.

I think we're about to see an example of this in exactly how Futaba handles their latest FASST issue. If they attempt a hush-up without telling customers honestly and truthfully what they find then I think it will backfire badly on their sales.

There is already a lot of discussion that Futaba might just try to do a snow-job on this -- let's hope that's totally unfounded.

I think the market is mature enough to realize that all of this 2.4GHz gear is going to have issues (at least in the early days) and that the most essential thing for manufacturers to do is to be open and honest about the cause, effect and solutions to those problems.

To give him credit, JD has acknowledged the frequency-hopping issue. I hope he continues to stay in touch with reality as the product goes forwards.

[sweetpea]

	Quote: Originally Posted by XJet
	So (just to clarify) you also don't believe JD's claims that XPS doesn't need satellite receivers for large models? As for diversity -- antenna diversity (such as that used by Spektrum/FASST) *does* work. Although it won't be as effective as a satellite receiver in the case of shielding caused by large reflective/absorbent structures, it does work very well in dealing with multi-pathing and polarization issues. In fact, fixed/close-spaced antenna diversity can (in some cases) be *more* effective than a satellite because you can ensure that the element spacing isn't an exact multiple of a wavelength and that the losses due to cross-polarization won't affect both antennas at the same time.. Antenna diversity is designed to ensure that one element is always likely to be outside of the null-point created by multi-pathing.

Now we are getting somewhere....

On Pt#1.....I told XPS I thought you needed multiple Rx's and not just one RX due to blockage issues. But even FASST says that isn't true, their one RX system with longer antennas is fine (I suppose it is if you can get past the blockage). Only Spektrum acknowledges its true and currently only spektrum gives you the ability to fine tune the placement of all its RX's. (Me like that feature alot)

On Pt#2.....antenna diversity. I've got mixed feelings here. I think both designs have pros and cons but neither eliminate blockage issues. A large 3W157w/cans that run down half my fuse is a pretty big blockage. Now add a fuel tank and smoke tank (if your into that). And depending on the orientation of your one antenna or 2 antennas you can still be blocked quite well, for at least some degradation. I stick to the satellites as being the cure for this issue or some 72mhz length antennas for the main RX (which really isn't possible freq wise).

Now on that topic, I believe that XPS satellites are single antenna as well while spektrum are dual. So that will be another topic of debate I'm sure if I remember the picture correctly.


As for Futaba.....I hope they don't sweep it under, but the track record isn't good. Plus all they have to say is......"new software update is up on the site" They don't have to explain why its there or what it does. Seems not many people question it, they just do it.

[sweetpea]

I wish I could make the AMA convention this year......I have tons of face to face questions for all 3 vendors!