mavrick

My Feedback: (1)

HI Guy's
I am after anyone that has first hand information or experienced a cell phone getting into 2.4 set up's, here in Aus there is a lot of hype about it. The only time that I know something weird that happened was when a guy at the field was binding one of his planes at the same time that another person was resetting the time on her Mobile phone,it went all hay wire and he ended up having to send it in to get cleaned out and reset to defaults, it was a 7 channel Spektrum. I personally have been on the phone around my Jets with out any prob's I run 9100's.
Regards
Mav

madmodelman

Mav,
I used to be in the mobile business, in the UK they operate on 1.8 ghz but even so a harmonic could possibly touch 2.4 ghz. if it was very close.

i.e. 1.8/3 = 62.4/3 = 8 therefore all multiples of three are harmonics if you get my drift.

1.8 is a universal GSM frequency so the same should apply where you are, of course when the model is in the air its rx is miles away from the handset and won't be a problem.

Hope that makes sense to you,

Gary.

junglejet

Mav, its a club by-law not to have them in the pit area. End of story!

Pete

mavrick

My Feedback: (1)

It's good to see you are keeping up with the latest goss Pete
mav

CraigG

My Feedback: (40)

I think the situation is similar to cell phones causing interference on airliners, lots of anecdotal tales but very little empirical evidence. In both cases (r/c airplanes and airliners), there have obviously been many flights with cell phones on and no problems.

But I think the attitude of most people is, why take a chance, and just turn them off (if you remember).

Craig

Nhalyn

There is the same sort of thinking about cell phone in hospital environment with medical stuff. Cell phones are forbidden "by care" on intensive health department, but "not forbidden" elsewhere in the hospital.

Moerig

Cellphone interference is real, just like any powerfull transmitter it can cause problems for any electronic device. Operating frequency has little to do with it. Cell phones emit RF in short high power packets that form very low frequency AM content. That is why FCC part 15 requires equipment to be able to accept a reasonable amount of interference without malfunction. Spektrum has had many design issues and the program flash is prone to corruption. many will no doubt have seen those gizmos that sometimes can be found on motorbikes that flash an LED in response to cell ringing. The LED is powered from the RF alone....

madmodelman

Cellphones do not emit "high power", they are very low, its the cellsites that chuck out the power.

rcguy!

My Feedback: (69)

Hmmm.... I've had my cell phone ring while flying jets with my JR 2.4 equipment. Not even a lost frame was recorded. Woulda been difficult to answer it, let alone talk on it at the time........
I couldn't tell ya anything else about the subject.

Dave

madmodelman

Lol!

Xairflyer

My Feedback: (1)

There were stories in the past with phones causing programming to be wiped from Futaba transmitters.
My Mazda convertible has a microwave alarm and if you put the phone in the car and turn on the alarm, then ring the phone, it will set off the car alarm!

Dont know of any actual official tests have been done re phones and transmitters, safest bet is to not have them on you when flying.

Chris Nicastro

My Feedback: (3)

At our field we have policemen in patrol cars who like to hang out near the entrance or they come in and watch us fly, its a private club on county land. So they do their reports and take breaks there. Well one of our guys was flying his large IMAC Extra 300 or something like that and while the patrol car was there he had his Futaba radio system blank out then recover and then on final to try and land safely it blanked out again and went to fail safe mode. He lost the plane. Sent everything to Fuataba, Fromeco, sent it all to have everything checked out....nothing, all is normal.
Right after the plane went down he said he remembers the patrol car left.

I had a similar incident that cost me my plane as well and it also involved a patrol car and Sherrifs helicopter in the immediate area.

Bottom line our devices are passive and all other radio traffic takes priority by FCC requirement. Unless you have a HAM or professional radio operators license so you could operate commercial grade radio equipment your pretty much subject to any other devices that are allowed to broadcast over our radio systems.

speed is life

A few years ago Multiplex actually put out a bulletin that warned MPX users against having a cellphone within (I think it was) 2-3 meters of a transmitter. It had not to do with 2.4ghz specifically but with the possibility of interfering with the flash memory of the radio. Something about the cellphone signal output/strength when it first initiates the link with the cell system on a call.

I just ask guys that are addicted to their cell & with the Bluetooth in the ear to stand a little farther away..........or I move away.
IMO more clubs ought to discourage cell use on the flight line, if for no other reason than distraction or lack of attention to flying the model.

Moerig

Wrong. GSM phones emit up to 1W and non handhelds are allowed 5W. The actual power transmitted depends on the signal strength reported back from the cell tower, that is the further away the cell is from the tower the higher the output. Which is why cell batteries last longer in dense cell areas than rural. The handset has the poorer of the antenna efficiencies. It is worth squat if the handheld cannot deliver the range the tower can, despite the antenna differences.
At any rate it does not require much power to interfere with a high impedance circuit. Interference in this case is not necessarily via the RF path, ie antenna.
Anyway Part 15 requirements state that if you experience interference you should move the source further away, not much use on a fast jet....
If you dont believe it, put your cell in your jet when flying and give it a call...

madmodelman

Chris, that does not suprise me, if you ever get a chance have a look in the boot of a Police car, the transmitter is huge and very powerfull!

Even our local police with small cars have a bootfull of radio equuipment and traffic cars have two lots, one for local and one to contact HQ often some fair distance away.

If anyone doubts me I am actually a amateur radio licence holder although I don't use it nowadays, not as much fun as a Jet!

Gary (G4XRD)

madmodelman

What you say is correct except that I would not call 1 watt powerful!

Xairflyer

My Feedback: (1)

So come on who is game

ash 26

xairflyer You can try it with your new Iphone4 the next time you are down

jeffEE

My Feedback: (5)

Now I would pay money to see that demo flight!

GerKonig

I keep my cell in the shirt pocket (so I can hear it), and fly w/o problems ever when it rings.

Anyway, never a problem, and we have people on the line talking from time to time, never ever an incident. But, I can see it is easy to blame the cell phones, or the cops, or whatever we can blame... I always drive to the field with the truck. and sometimes, I fly when there is nobosy at the field. So, if I ever have a problem, and I crash, I am blaming the darn truck...

Gerry

sljensen

My Feedback: (6)

Everyone seems to be forgetting that there is RF of all sorts coming from electronic devices. It doesn't have to be on the same band that the electronic device operates on. The RF could be coming from one of the boards inside the device, or one of the processors. If you are trying to bind a receiver to a signal, it will be looking for whatever it can find. You could have two identical phones and one could cause interference, and the other wouldn't. If quality control was perfect there wouldn't ever be a problem with anything.

mavrick

My Feedback: (1)

Thanks for the responce guys, as you can see from my mates reply earlier on we have a bylaw in our club not to have cell phones on the flight line or in the pitts but it is hard to police because people leave them in there pockets (me included sometimes) I have yet to see any interference with a plane in the air but I TOTALY agree with Pete it is far better to be safe than sorry after something happens and mybe some one gets hurt. I would hate to be bending over with the pointy end coming at me. LOL
Regards
Mav

GerKonig

In a little over one week we have a great Warbird show here, one of the big ones in the east coast. The Warbirds over Delaware airshow. You will have a handful of models in the air at all times, and during noon they put like 30 1/4 scale WWI models in the air at the same time. All while you have hundreds and hundreds of onlookers and participants. I can assure you that at all times you have dozens and dozens on cellphones in use, and no problems with the airplanes.

SAID THAT, if you are at your field and someone crashes for whatever reason, and you are using a cellphone I bet you will be blamed:-) (because people are just stupid, and will need something to blame, and you would be an easy target).

Gerry

Moerig

From that point of view it is not really a problem. That said what could be an issue (The OP's scenario) is when the cell is in close proximity to another piece of electronics like the CPU's in the TX and RX, induced RF power can cause memory malfunction if the equipment is not properly designed.
Pacemaker mfs had this scare in the early days of cell technology, real or perceived.

Xairflyer

My Feedback: (1)

Someone official AMA, JPA, BMFA etc need to do some tests or maybe Bruce from RC Model Reviews.