Independent tests prove lack of frequency hopping with XPS

[KrisW]

	Quote: Originally Posted by ASSAN
	hi, guys. i am disappointed that some body told the people that without hopping system is not as advanced as hopping system,easy broken when it's meet nosie. i must say that is wrong,because X8 is one ch system without hopping. that report hurt us and make customers worry about what he purchase. i need told the customer the fact, that they don't so clear know what happened in the new commuicate technology. in fact, one channel 2.4G system can keep solid in the noise condition.if it's not better than hopping,it's equal to.i think. lets look at the pictures, i shot them this morning.that proved that without hopping,X8 system is still keep solid in full nosie conditon.

Assan, it goes without saying. . If a system does not have the ability to change frequencies, as Futaba and FASST does, then it is not as advanced as one that does. That is very simple.

If it does not transmit on more than one frequency, as Spektrum does, it is NOT as advanced or interference proof as one that does. Again, it's as simple as that.

Currently there are two more advanced, more capable, and more interference/shootdown proof systems on the market, those are Futaba and Spektrum/JR, with the Sanwa/Airtronics system coming out soon. EVERYTHING else, up to this point is not as advanced, more prone to getting shot down, and less capable than those three systems.

Whatever you believe about the single-frequency/non-hopping 2nd tier systems out there, they are not as good as those provided by the 1st tier players.

[BZFrank]

	Quote: Originally Posted by ASSAN
	i must say that is wrong,because X8 is one ch system without hopping. that report hurt us and make customers worry about what he purchase.

I did test Assan and also done some RF plots. While I consider the system rather solid, I believe that in the face of RF interference its performance is lower than FASST or Spektrum. For the system interference on its allocated 'channel' is seen as an increase in noise level. It is possible to cut into its range performance e.g. by activating a 2.4 Ghz FM video transmitter right on its allocated band. Also I notice a higher antenna alignment dependencies at long range compared to FASST or Spektrum - which I think is due to the single antenna in the receiver (I used the 8ch, the 6ch with its dual whip antennas gave me only about half the range!).

Don't get me wrong - I think it does work and for its money I consider it it good value. But I think it lacks

- Frequency Hopping (also in the face of EU restrictions, I am sure you like to sell to this market in the future), or another form a frequency agility scheme.

- RX antenna diversity

[Fish07]

Very simple,NO BACKUP !!!

	Quote: Originally Posted by ASSAN
	hi, guys. i am disappointed that some body told the people that without hopping system is not as advanced as hopping system,easy broken when it's meet nosie. i must say that is wrong,because X8 is one ch system without hopping. that report hurt us and make customers worry about what he purchase. i need told the customer the fact, that they don't so clear know what happened in the new commuicate technology. in fact, one channel 2.4G system can keep solid in the noise condition.if it's not better than hopping,it's equal to.i think. lets look at the pictures, i shot them this morning.that proved that without hopping,X8 system is still keep solid in full nosie conditon.

[Kiwi]

OK guys,

Last night I finished the testing of all four systems in the exact same environment. The results are not unexpected. The tests used an ASSAN 8 channel system, FASST 7 channel, XPS 10 channel and Spektrum 7.

The videos have been rendered and now I need to tone them down to a 60 Mb size or less. They are currently 2.5Gb each and I dont see Max wanting me to burn up that much space on the server.

Anyway the testing was down right simple with no fancy bells and whistles. I used a scanner to show the noise levels and interference I produced. I used a traversing signal generation so each WiFi band was hit with 10 seconds of signal in sequence so we went from Channel 1 to 13 in 130 seconds.

The receiver was setup with a servo on a degree wheel so we could see any jerky movements and failsafe or holds.

The radio was a FUTABA 8UAPs, old but sturdy for three of the units and the Spektrum was a DX7 as I was unable to get the module for the Futaba radio.

I will post the videos here and on You Tube so for those who dont want to log in or sign up they can still see them.

The results are my findings and I make it absolutely clear that I have no bone to pick with any of the system manufacturers and I have no hidden agenda doing this. I done it because I wanted to know for myself.

Both XPS and ASSAN are single channel non hopping systems. They were both easily put into hold or failsafe with some signal or interference generated by my setup.

FASST and SPEKTRUM were both impossible to get to go into failsafe or hold in the exact same conditions as the single channel systems. That is you would not know you were in a high noise environment with them as they simply showed no sign of failing.

However that does not mean they are perfect and bullet proof. What this testing does prove beyond any doubt is that FASST and SPEKTRUM have much higher tolerances in a noisy or high interference flying environment. NOTHING ELSE.

I used ASSAN on some of my small foamies and electric helicopters. It works perfectly in our local environment.
I would use XPS in the same circumstances if I had to. XPS is a very well designed and very powerful package but it just lacks the collision avoidance capabilities that FASST and SPEKTRUM have.

So when it comes to looking after my large scale or high priced toys I go for the most resilient system. To me thats FUTABA or JR. I cannot justify saving $50 on a radio if it puts at risk a $5000 plane. The common sense tells me my maths would be wrong there.

One thing that clearly sets the higher end systems apart from the simple and lower priced setups is lack of antenna diversity or the capability of adding it to existing units and the inability of them move away (hop frequencies) from an oncoming lockout or failsafe situation.

I know there are more systems coming such as Airtronics and Weatronics. Both these units will be FHSS and the later will apparently be a two channel FHSS system if the rumors are right.

Gents, there you have it. Its my opinion and mine only, totally unbiased and factual. The choice on what you fit or like or use is totally a personal thing. All I have tried to do here is show the strengths and weaknesses of the four systems in a noisy interference prone environment.

If and when any new systems come available I'm sure we will get our hands on some and test them in the same environment.

The vids will be up tonight guys so hang tight please.

[Fish07]

	Quote: Originally Posted by Kiwi
	OK guys, Last night I finished the testing of all four systems in the exact same environment. The results are not unexpected. The tests used an ASSAN 8 channel system, FASST 7 channel, XPS 10 channel and Spektrum 7. The videos have been rendered and now I need to tone them down to a 60 Mb size or less. They are currently 2.5Gb each and I dont see Max wanting me to burn up that much space on the server. Anyway the testing was down right simple with no fancy bells and whistles. I used a scanner to show the noise levels and interference I produced. I used a traversing signal generation so each WiFi band was hit with 10 seconds of signal in sequence so we went from Channel 1 to 13 in 130 seconds. The receiver was setup with a servo on a degree wheel so we could see any jerky movements and failsafe or holds. The radio was a FUTABA 8UAPs, old but sturdy for three of the units and the Spektrum was a DX7 as I was unable to get the module for the Futaba radio. I will post the videos here and on You Tube so for those who dont want to log in or sign up they can still see them. The results are my findings and I make it absolutely clear that I have no bone to pick with any of the system manufacturers and I have no hidden agenda doing this. I done it because I wanted to know for myself. Both XPS and ASSAN are single channel non hopping systems. They were both easily put into hold or failsafe with some signal or interference generated by my setup. FASST and SPEKTRUM were both impossible to get to go into failsafe or hold in the exact same conditions as the single channel systems. That is you would not know you were in a high noise environment with them as they simply showed no sign of failing. However that does not mean they are perfect and bullet proof. What this testing does prove beyond any doubt is that FASST and SPEKTRUM have much higher tolerances in a noisy or high interference flying environment. NOTHING ELSE. I used ASSAN on some of my small foamies and electric helicopters. It works perfectly in our local environment. I would use XPS in the same circumstances if I had to. XPS is a very well designed and very powerful package but it just lacks the collision avoidance capabilities that FASST and SPEKTRUM have. So when it comes to looking after my large scale or high priced toys I go for the most resilient system. To me thats FUTABA or JR. I cannot justify saving $50 on a radio if it puts at risk a $5000 plane. The common sense tells me my maths would be wrong there. One thing that clearly sets the higher end systems apart from the simple and lower priced setups is lack of antenna diversity or the capability of adding it to existing units and the inability of them move away (hop frequencies) from an oncoming lockout or failsafe situation. I know there are more systems coming such as Airtronics and Weatronics. Both these units will be FHSS and the later will apparently be a two channel FHSS system if the rumors are right. Gents, there you have it. Its my opinion and mine only, totally unbiased and factual. The choice on what you fit or like or use is totally a personal thing. All I have tried to do here is show the strengths and weaknesses of the four systems in a noisy interference prone environment. If and when any new systems come available I'm sure we will get our hands on some and test them in the same environment. The vids will be up tonight guys so hang tight please.

OK guys,there you have it ,as simple it can get ,THX Kiwi !!!

[Kal]

Kiwi I would be curious to know if you have the equipment to swamp big portions of the 2.4ghz band. For example I would be curious to see what would happen if you swamped the whole half of the 2.4ghz band either in the middle or from either end. Obviously if that half happened to fall on the half that Spektrum's two channels were on you would end up with lock out however I'm curious if the FASST system is capable of dealing with such a great ammount of noise and still work (probably see some slugish response). Basically I would be curious to see how much of the band you can swamp and still have the FASST system respond to inputs in a way that would allow you to land or have a decent degree of control. It seems FASST which hops the entire band would be the only one that would have a chance at working through such an environment. This to me would be the ultimate test in interference avoidance.

[Four Stroker]

This could easily be done if Kiwi can borrow a couple more WiFi signal generators and run them simultaneously on fixed channels. A microwave oven will jam a large portion of the upper band. However, I have taken my cheap spectrum analyzer to the field and there is no persistent interference that would even lockout a single channel system.

Flying fields for 40% planes tend to be in the outback anyway. Urban outlaw fields are big enough for helicopters and might have a much higher noise floor.

[jonkoppisch]

AAAAKKKKK... I was just told by jd to not post any messages in his paid forum or he will ask that I be banned from the area completely....

& threads are deleted again...

[Fish07]

	Quote: Originally Posted by jonkoppisch
	AAAAKKKKK... I was just told by jd to not post any messages in his paid forum or he will ask that I be banned from the area completely.... & threads are deleted again...

i think i haved been banned forever!!!

[Kiwi]

Gawd durn it fourstroker.

Its not the Airhorns that cost the bucks, its the darned computers. You know at the peak of my meddling to get a scenario that was totally repeatable I was running four computers together.
1. Scanner
2, Backup scanner with different software
3. Airhorn signal generator
4. Video editing (Mac) as I hate Windoze video.

But there is a way I can try out your theory and that is if I make lots of end range noise (say 1 to 3) with a crappy video camera, Use the airhorn to make lots of noise mid range that will squeeze SPEKTRUM into the far end of the frequency and it will select two channels side by side if you dont give it anywhere else to hang out.

I will try it but not this weekend please mate. My flying has turned to bulldust as I have been playing techy and pit B(*&^% for the kids on weekends. Plus I'm headed to the Nall and gonna have a right royal ball meeting all you guys again or for the first time.

First vid is being loaded as we speak. FASST is first cab off the rank.

[Kiwi]

OK,

Here they are.

The first three out of the box. SPEKTRUM will be tomorrow as I'm bushed tonight and need a decent nights sleep for a change. I will put the SPEKTRUM vid in here as soon as Youtube get it converted guys.

YouTube - FASST testing in a controlled noise...

YouTube - ASSAN 2.4Ghz controlled noise...

YouTube - XPS bench test in an interference...

[Toumal]

Kiwi, thanks for your most excellent work on those videos. Very informative, and with a shockingly clear punchline. Now I'm anxious to see how Spectrum fares under these conditions.

[Kiwi]

That video is done and you will see it this afternoon. It performs exactly as advertised if that steals the punch line.

Hang in, its a holiday here and the kids have demanded a little attention.

[Prof. Dr. YoMan]

Just raise the bandwidth of the noise. If the noise eats up more space Spektrum is
the next to fail whilest FASST will still be going (maybe with some additional latency).

[Toumal]

There's certainly going to be a point when even FASST is going to fail. For example, if someone were to use the same hopping sequence, that could be trouble.

If you want to survive even such deliberate interference, you'd need VDL Mode 4, (edit: I mean the methods employed there to counter interference, not the frequency band ) which unfortunately is beyond the scope of companies like Futaba. And even then, there's a point where either the signal is too weak or the interference is too wide-band and powerful.

It would be really interesting to see what it takes to actually kill FASST via deliberate band-wide interference.