2.4 Gigs sytems

[monty]

There are now two manufacturers, Futaba and Spektrum, using two different types of communication on the 2,4 Gigs band.
The Spektrum system utilies an unused channel (there are 40 channels I beleive) while the Futaba system continually from one channel to the next. I read in RCME that Thunder Tiger now have a Video link system operating on 2.4 Gigs.
If two or three of these different types of systems are in use simultaneously is there going to be a problem?
In the States JR have released their new 2.4 Gigs system, this is the JR PCM 9X2
transmitter with the Spektrum 2.4 Gigs technology.

[Danny Fenton]

A friend who flies with a Spektrum 2.4 suffered a Tx failure at the weekend which resulted in the model diving into the ground at full tilt. When the transmitter was tried with the other three models he was intending to fly (all fitted with 2.4 Rx) all had lost range, full control only being effective over about 6 yards, so the problem was clearly the Tx not the Rx. Anybody else have any instances of this?

[Tim Mackey]

Hi Danny, I am aware of this incident, from a thread over on "another forum" :-)
I did some extensive testing of my Spekky system, and could find no issues with range in the dry or wet ( results are on that thread. The only issue I have ever had was due to switching on the receiver BEFORE the tr which is not good practice anyway, and sometimes in this scenario he receiver would not react at all, as if it was not bound. Simply solved by switching on tr first, then recevr, and waiting a few seconds to ensure that the link is established.
As for compatibility problems with the 2 systems ( incidentally Spektrum use TWO channels simultaneously not ONE ) and the Futaba uses what is called FHSS Frequency Hopping Spread Spectrum I have flown at a meet recently together with a guy on the Futaba system, and neither of us had any problems.

[Danny Fenton]

Hi Timbo, I am only saying what we found, the fact that the three other models all displayed the same problem using that Tx says to me it isn't a useage problem ie they were switched on in the wrong order. My friend is not daft LOL if it were a model installation issue then it should have shown up in previous succesful flying sessions. The range checks did show control up to 18 feet, then the controls all started moving with a 1 second delay. as the range was increased further then the failsafe cut in. It is most odd. As you have seen the thread elsewhere you are no doubt aware of the reply from Horizon after they tested it? No fault found.

[Tim Mackey]

Hi Danny,I was not suggesting that your friend was at fault, from his reports it appears he has a good grasp of the system, and I am sure he is not thick LOL.
As of this morning, your friend has not reported any response from HH about this particular transmitter ( I assume we are talking of "squarehead" on RCMF ?? )
I understood it to be the other "faulty" transmitter he had returned earlier which was diagnosed as NFF, and that this latest will take 2-3 weeks turn-around for a report.

[Danny Fenton]

Hi Timbo, yep its "squarehead" LOL, it is always possible I have the wrong end of the stick(scuse the pun)LOL I was in a group chatting with him at club night on Wednesday and that was my take on what he said. I knew that he had a previous problem but thought that was resolved some time ago. That would explain how they had reported back to him so quickly, which did surprise me. I do hope we find out what is going wrong, whoever is to blame, so that we can make reliable choices. We are all wondering which way to jump.

[Tim Mackey]

Yes, me too, it is always sad when we lose a model to radio failure, and this, despite being on 2.4Ghz was exactly that...a radio failure, something which most of us have suffered at some time or another, on "old" 35mhz too !
I have already "jumped" last year, and fly ALL my stuff on Spekky, and although I like it a lot, no-one, including me, can rule out the possibility of failure, as in ANY R/C installation, aeroplane, mechanical/electronic device etc etc.
This is not the holy grail of control systems, purely because the holy grail is fictional :)

[Danny Fenton]

LOL Indeed, I for one have never had so much as a glitch (ruined it now!) on my PCM9XII with JR Rx's but they are £90 each. Some of the members are using Multiplex Rx's and have had similar success. I do wonder whether the power levels we are allowed to emit are too low. Do you know how the output levels compare to other devices? Mobiles etc??

[the unmagnificent man]

Hi all, in answer to Monty's original question. No i dont believe for for one second that there will be a problem if 2 or more people switch on a 2.4 Futaba systems at the same time, reason being is that because the Futaba switches its frequency every milisecond (or 2 miliseconds if your picky) you would have to have a million random switches matching your clubmates million random switches to cause him to take control of your plane or vice versa. Even then it would only be for 1 second. The probability of that happening would be similar to matching the lottery numbers every weekend for a long time. Al

[Chris Bradshaw]

Our transmitters aren't the only bits of equipment to use the 2.4Ghz band.
Most wireless routers do, as do video link systems to name but 2.

What's to stop any of these 'other' systems from interfering with our much more important equipment?
Could we see more crashes due to interference because some twit down the road bought a cheap wireless router on import that doesn't conform to UK rules & regs?

[Tom Sharp]

On my computer the mouse and the keyboard are on the old 27Mgs.

[Tim Mackey]

Chris. ALL "approved" 2.4Ghz equipment ( which is pretty well every item sold over the counter as it were )must conform to a worldwide protocol that prevents it from interfering with other 2.4Ghz. It is known as GUID ( globally unigue identity ). Each of the receivers and transmitters we use in our hobby also have to "talk " to each other...or BIND as Spekky calls it, and after successful binding, that receiver will ONLY receive instructions from its "partner" transmitter.
As I said in an earlier post, I have a lot of confidence in my Spekky stuf, so much so that ALL my models are on it, however i also said, and still believe that NO RADIO SYSTEM can be guaranteed to be completely secure. That said, I am not aware of ANY incidents of actual interference within our systems which has manifested itself as a problem, and I personally have flown in mixed company of futaba 2.4g, and several other spekky pilots on the flight line too, with no-one reporting any problems whatsoever.
Incidentally, I also use 2.4Ghz wireless k/b mouse, and have a wireless LAN router and switch unit operating 24/7 and have deliberately tested the spekky stuff in all sorts of ways right up close to it.....no prob at all, ever.

[Tim Mackey]

Incidentally, the problem which Danny mentioned earlier, about his friend who had experienced a Spektrum transmitter having no range, on any of 3 model selected appears to have been diagnosed as a faulty link in wiring to the aerial. Im sure Danny will update us further if necessary. This sort of "fault" could of course just as easily occur in any R/C transmitter 35Mhz included.

[Danny Fenton]

Hi Timbo yes you have reminded me to ask SquareHead next time I see him. He hasn't been about of late