Independent tests prove lack of frequency hopping with XPS

[wrightme]

	Quote: Originally Posted by hillmanr2
	I had obviously incorrectly assumed that GUID codes would stop interfering signals on the same band. They obviously do not. I do not have an understanding enough of the way 2.4 works but if I can be shot down by some guy on a computer a block away(perhaps overly simplified but more than plausible)

You did not assume incorrectly, but oversimplified.

NO RF signal is immune from flooding of a frequency band. That GUID code is supposed to be NEVER the same as another piece of hardware. Futaba messed up if they are the same in some cases. That is not to lead you to assume that a computer WiFi can shoot you down.

It has been said before, but maybe not understood that plenty of these problems WERE evident with 72mhz (and 35, etc.), but are NOW much more understood with the advent of 2.4ghz. I will enjoy my XPS systems where I fly, and MUCH enjoy the removal of checking with other 72mhz fliers for frequency use. In fact, some channels of 72mhz just do NOT work well where I fly, and it is more than 5 miles from ANYTHING that should be an emitter, except for one LORAN tower. Sure there are crashes, and a fair number that lay blame on any specific system are in fact UNEXPLAINED! In the 72mhz world, such crashes were left unexplained, and it was assumed that the crash was from getting "shot down."

PERCEPTION is the big thing that has changes. With 2.4ghz, the assumption in "unexplained" crashes has shifted from "shot down" to "new tech problem." Until a PROOF is provided, they are conjecture.

[dick hanson]

Nice wright up!
Seriously
Each time I see the statement " I will stick with 72 till 2.4 is proven". I wonder "what needs to be proven to whom and compared to what?

[sherman89]

Good bye XPS, HELLO Futaba 2.4 Fasst!!!!!!

[JimC-MD]

Just so I am on the record. Hehe.

I am nervous flying on 72. I fly at a field that is only one mile as the crow flies from a county park. We are an AMA sanctioned field and have frequency control. People buying park sized planes in spades around here and "renegade flying" are the concern. I had my first unexplaned event with a plane last year. It was a Goldberg Cub on 72 with a Saito 100. Equipment that had been used in other planed. I was lined up on an inverted approach to the field and the plane was going in and out of hold. Throttle to idle, no response, get it back, then hold then back then hold and crash. Just missed a building and a big Ford pickup. Everything checked out afterwards. Someone came up after I had collected the pieces and asked if I was done with Channel 18. Did they accidentally shoot me down? Who knows. They were pitted on the side of the field I was approaching from. What ever. The plane is repairable with no major camage. Still, in over 20 years of flying, that was my second "loss of control" due to non dumb thumb events. The first was a battery that died second flight in 1988. The concern is that it could have as easily been one of the gassers with more of a loss and more potential damage, like Xjet has mentioned.

I and my inlaws have been flying on 2.4 for over six months with no issues at all. We have been flying mostly Spektrum and they have been using one FASST 6 channel. It has been on birds up to a Funtana 100. I am still thinking about the move to put my Dalton on 2.4. I have been leaning that way. That is why I am so interested in any accurate testing. I am hopeful that by the time I am ready to maiden this bird, some testing will be out there. I was at the Nall when they had something like 15 birds in the air at the same time last year, all on Spektrum and took them WAY out and UP. Giants, Jets, you name it. The 2.4 was unregulated and you could fly foamies off to the side at any time. I heard no complaints and saw no issues. I heard guys that were flying 72 that were having issues. Holds and twitches. These were nationally known demo pilots that were talking about easing off the routines they were doing because of a lack of confidence on 72. Hmmmmmm. Even with the concerns, I am still leaning toward 2.4 and a data logger. My thinking is to be as much of a stickler with pulling datalogger info as I am checking batteries between each flight. The other though process would be to train my mind to potentially cycle the power on my TX if I had trouble and time to do so. I do not know if this would be a useable extra step or not. My thinking is that it would be a potential way for the TX to see the better channels open and shift to them. I would like to see this tested to see if the RX would actually shift over if it was swamped out on the starting channels. Or is the quick rebind feature design to quickly try to reaquire the last two channels that are stored in some type of KAM (keep alive memory). Xjet and Kiwi, this may be something to add to the pile as a suggested or not recommended protocol. If altitude is where we tend to increase "issues" the time to the scene of the crash would increase. I am interested to see if the FASST system has any issues as well. Do not know how I would test that. Is there any was that the sync of the two units could be lost? If so, what does it take to reaquire the "dance steps"? Is this really a specially designed chip, or is it something that Futaba has been using in industrial applications that they have adapted to RC? That was how I understood it. "We have been doing this for years" type of information. If it is such a good system, why did they not press it into service earlier? Makes me wonder. My pessimistic side says because they know that the types of issues that Xjet and others have raised are real. It could also be that they would have been stuck with too many old radios they could not move......

Enough of a ramble.

Good day all.

[XJet]

	Quote: Originally Posted by sherman89
	Good bye XPS, HELLO Futaba 2.4 Fasst!!!!!!

Given the GUID probelms facing FASST right now I have two words to contribute: fryingpan, fire

:-)

I'm sure Futaba will sort the problem, it's just a shame that their technically superior system appears to have been shot down, not by interference but by a design glitch.

The way Futaba handles this will be very revealing and probably a huge factor in their continued success in the 2.4GHz marketplace.

No 2.4GHz system on the market today is without its problems -- that's why we need to do a head-to-head comparison of strengths and weaknesses.

[XJet]

	Quote: Originally Posted by dick hanson
	Nice wright up! Seriously Each time I see the statement " I will stick with 72 till 2.4 is proven". I wonder "what needs to be proven to whom and compared to what?

It's a "horses for courses" situation Dick.

Where I fly we have quite a bit of 2.4GHz traffic once you get up to 100 feet or so but, despite this, we've had good results with all the 2.4GHz systems that have flown here (even the cheap Chinese stuff).

However, I stick with 72MHz for my more expensive models because we simply don't have a problem with interference on that band at all.

I've left the 72MHz monitor on all day and it never gave a peep -- which means that it's a *safer* operating band than 2.4GHz -- AROUND HERE.

There's also zero risk of being shot down by another flier on 72MHz here because everyone in our club has their own frequency on one of the 35, 36, 40, 72MHz bands that are available to us (we have 136 individual frequencies available on these bands!). The only time I've ever had to wait for a peg is when we have a well-attended meet, and even then there was only *one* other guy on my frequency.

Now I know there are locations (in the US and elsewhere) at which the 2.4GHz noise levels are problematic. It would not make sense to fly 2.4GHz RC systems there because the risk of lockout/loss would probably be too great.

Likewise, there are fields where the noise on other bands is too great for reliable/safe flying so 2.4GHz may be the best option.

The thing is that we can't simply say that 2.4/72 is "best" because it's highly dependent on your flying environment.

I notice that some of the losses attributed to XPS have occurred when, after many months of trouble-free flying, people have gone to another club or event then found themselves with a smoldering wreck on their hands. Their own field may have been 2.4GHz-friendly, the other field probably wasn't and given that it appears XPS is the least able to handle interference (no redundancy, very limited hopping), they went in.

As I've said before, what the RC market needs is some dedicated spectrum where we're not fighting for space with mobile phones, wireless internet, leaky ovens, cordless phones, wireless TV transmitters, pagers, etc. If we can get a nice piece of quiet spectrum then it wouldn't matter if we used spread spectrum or auto-negotiating synthesizer-based narrow-band gear -- the hobby would be a whole lot safer.

I expect that the annual loss of models to the interference we currently have to endure (on 72 and 2.4) would be far less than the cost of leasing a MHz or two of spectrum somewhere safe.

[dick hanson]

	Quote: Originally Posted by XJet
	It's a "horses for courses" situation Dick. Where I fly we have quite a bit of 2.4GHz traffic once you get up to 100 feet or so but, despite this, we've had good results with all the 2.4GHz systems that have flown here (even the cheap Chinese stuff). However, I stick with 72MHz for my more expensive models because we simply don't have a problem with interference on that band at all. I've left the 72MHz monitor on all day and it never gave a peep -- which means that it's a *safer* operating band than 2.4GHz -- AROUND HERE. There's also zero risk of being shot down by another flier on 72MHz here because everyone in our club has their own frequency on one of the 35, 36, 40, 72MHz bands that are available to us (we have 136 individual frequencies available on these bands!). The only time I've ever had to wait for a peg is when we have a well-attended meet, and even then there was only *one* other guy on my frequency. Now I know there are locations (in the US and elsewhere) at which the 2.4GHz noise levels are problematic. It would not make sense to fly 2.4GHz RC systems there because the risk of lockout/loss would probably be too great. Likewise, there are fields where the noise on other bands is too great for reliable/safe flying so 2.4GHz may be the best option. The thing is that we can't simply say that 2.4/72 is "best" because it's highly dependent on your flying environment. I notice that some of the losses attributed to XPS have occurred when, after many months of trouble-free flying, people have gone to another club or event then found themselves with a smoldering wreck on their hands. Their own field may have been 2.4GHz-friendly, the other field probably wasn't and given that it appears XPS is the least able to handle interference (no redundancy, very limited hopping), they went in. As I've said before, what the RC market needs is some dedicated spectrum where we're not fighting for space with mobile phones, wireless internet, leaky ovens, cordless phones, wireless TV transmitters, pagers, etc. If we can get a nice piece of quiet spectrum then it wouldn't matter if we used spread spectrum or auto-negotiating synthesizer-based narrow-band gear -- the hobby would be a whole lot safer. I expect that the annual loss of models to the interference we currently have to endure (on 72 and 2.4) would be far less than the cost of leasing a MHz or two of spectrum somewhere safe.

You certainly have a vastly different soup of frequencies than we enjoy!
Around here 72 radios are constantly being dug out of the attic and stuck in the RC car -etc..
So 72 -for me, is really a crapshoot and will get worse as others get rid of of theirs . My 53 .xxx alway worked well and was successful in guarding against the occasional abandoned Kraft, etc..

[hillmanr2]

I leave one more post with what I should have said in the first.

I do not understand why the radio manufactures jumped to 2.4 in the first place with the exception of re marketing old products on a new frequency and call it cutting edge. (seems self evident)

The big thing about,2.4, already coined "the wild west" uncontrolled freq. was the elimination of shoot downs by fellow pilots. This is a very easy situation to control on 72mhz. All that would be required is for every 72 mhz radio sold from now on, to scan for unused channels the way 2.4 does and polk hobby radios( no I don't use one) and not transmit on used channels and bind the same way 2.4 does, on 2 free channels although this is not necessary. This would allow 30 users at a time. Don't bother with the GUID thing, it would not matter as 72mhz is a controlled freq and it is a software program not a radio necessity. Rc'ers would then still have a dedicated, shoot down free, frequency tag less, environment, not subject to the increasingly noisy environment of 2.4. which I bet will be to screwed up to use by most within 2 years

My last 2cents, I truly feel like we are being duped on this 2.4 thing.

Anywho I look forward to reading all of your findings and that you xjet and Kiwi for your dedication!

[sweetpea]

Except.......I would then have to look at the board for 2 freqs to make sure no one turned on an older radio while I was flying on my new radio. All your method does is protect me from shooting someone else down. It does nothing to stop an older radio from shooting me down with the new software.

The problem lies in how do you protect the new radios from the old radio's. You can't....so you have to go to an entirely new freq where every radio is using the new format.

And don't even get into freq control at a major event when each radio is requiring 2 freqs......No thank you on that!

[XJet]

	Quote: Originally Posted by sweetpea
	Except.......I would then have to look at the board for 2 freqs to make sure no one turned on an older radio while I was flying on my new radio. All your method does is protect me from shooting someone else down. It does nothing to stop an older radio from shooting me down with the new software. The problem lies in how do you protect the new radios from the old radio's. You can't....so you have to go to an entirely new freq where every radio is using the new format.

Which is why such a move must also coincide with the allocation of new (dedicated) spetrum to RC flying.

If one of the conditions of type certification was that it had an intelligent auto-frequency select system then there'd be no problems and *everyone* would be happy.

Why aren't (or are?) the AMA using some of their members' money to really push for this?

Both 72MHz and 2.4GHz are far from ideal solutions to the problem and both are far more susceptible to woes than such a dedicated band with a strict certification requirement.

[wizard]

As an answer to the question about frequency allocation. The problem is trying to find an open area of the radio spectrum. Here is the US frequency allocation chart.

[RH1N0]

FYI... but not intended to derail this thread.

http://www.rcgroups.com/forums/showa...mentid=1660908