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CANOMOD . Experience RC . Heli-Max

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Main Discussion > Mobile Phone and Synth TX warning
 
 
BigChopper
Key Veteran
Location: Cambridge, UK

My Posts This: Topic  Forum

I think whether you consider it Dave's fault for having his phone in his pocket or not... It is a very real situation which is going to be difficult to control and have some potentially serious safety consequences..

I think if you tried to claim off a person who casually walked up to you, a pilot or not, who happened to have their phone in their pocket, you would have a hard time convincing them it's their fault... and add into that any serious injury.. it could get really nasty. A definate grey area.!!

CE marking is given on a product which is 'fit for purpose' in its usage situation, taking into account safety, radiated emission AND immunity. Not all standards are applied to all products, but clearly a GSM immunity test is appropriate in this situation.??
12-29-2004 Over year old.
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Dave Hollins
Senior Heliman
Location: UK

My Posts This: Topic  Forum		At last someone that can see the problem...thanks BigChopper.

As for the other comments:

"""did you program the failsafe before your test? I am pretty sure that it will acted like a normalish PPM rx unless you program the failsafe point."""... Yes I did!!! ..that's what you do with IPD

"""I am 90% sure that the situation would have been different if you had used a correctly programmed IPD rx."""... I have a video of the crash and I tested the IPD RX (With failsafe!!!!!!) and I am 200% sure the result would have been the same. I can prove this with one of your helis if you want
12-30-2004 Over year old.
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Dave Hollins
Senior Heliman
Location: UK

My Posts This: Topic  Forum		If you switch the TX off you lose the signal totally and the IPD goes into fail safe after 0.5 sec. With the phone situation it didn't go into fail safe after 0.5sec, eventually it did? it's not deterministic.

I don't think you can gurantee what the TX is outputing in the mobile phone situation. You are trying to get involved and give reasons without seeing the effects of this interference!!! Are you sure you don't work for Multiplex!!

The Cobra was about 12 feet off the ground in the hover, the controls went to, what appeared, full travel. The heli flipped on its back and hit the ground. Even if the IPD was fitted, it would not have saved the model.

I have been flying RC models for 30 years and I started my working life in Electronics, so I do have some idea what I'm doing

We can talk about this for weeks and nothing will resolve the issue. There are few more warnings for poeple to read. The Synth module is still on the market. The time bomb is ticking
12-30-2004 Over year old.
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Dan C
Senior Heliman
Location: Barnsley, Yorkshire

My Posts This: Topic  Forum		just a note on the CE marking I have found that a UK company has to jump through hoops to get the CE mark as the test houses in the UK charge big money per day £1K+ and are very keen to maximise revenue at the same time the germans french etc think its a way of excluding UK companies from their internal markets where we will let anything through once it has the CE mark.

I think you can get a CE mark with a file on the product that follows a set proceedure on tests and other odds and sods but does not actually require test to ensure it does not emit or suffer failure from emissions

I have even seen a few spark erosion machines with CE marks that radiate noise that can be detected by a simple radio so I am not so sure the CE mark is the golden standard to look for
12-30-2004 Over year old.
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jimmyhua
Veteran
Location: Guam

My Posts This: Topic  Forum		Just an FYI,

It's not just the Multiplex Synth Modules that have this problem.

Even the Futaba 9Z WC2 Synth Modules have this problem (it's been around for a long time).

All you need is a GSM phone to ring within 6 inches of the Tx, and your servos go crazy.

As far as I know, the old analog phones, TDMA, and CDMA == no problem.. Also, all you need is about 2 foot distance and you are okay.

I haven't had a chance to test other synth modules. But I am suspecting these are fixed. Namely, the Hitec Spectra Synth Module, and the new 9CHP Super synth module doesn't have this problem. Anybody with a GSM phone have a chance to test these yet?

Jimmy

P.S. For the Nokia engineer that says this is impossible. I'm using a Nokia 3390

“No, try not! Do or do not, there is no try.”
12-31-2004 Over year old.
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jimmyhua
Veteran
Location: Guam

My Posts This: Topic  Forum		Well,

I just tried the Hitec Spectra Synthesizer Module + GSM phone.

It fails the test. Servos go crazy with PPM, servos go into lockout with PCM.

2 feet away, and PCM is fine. PPM shows "signs" of interference.

Keep your phones at least 2 feet away from your transmitters.

Anyone got the new "Super" synthesizers for the Futaba 9C and 9C Supers? I wonder if they got it fixed here.

Jimmy

BTW, I also have an analog phone and TDMA phone. Tried it with that, and it shows minimal interference. Sorry CDMA has not reached Guam yet. However, we do have Sprint PCS (which I think is a variant of CDMA), Gotta try that sometime, I don't have that service though.

“No, try not! Do or do not, there is no try.”
12-31-2004 Over year old.
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BigChopper
Key Veteran
Location: Cambridge, UK

My Posts This: Topic  Forum		Jimmy,

It is not possible to qualify the 2 feet result, because you have no idea what output power level your phone is at.

Further away from the basestation and answer _could_ be 4 feet.

I'm afriad you cannot really get a decent result without the proper test equipment. If you are happy with this for yourself then go with it, but use extreme caution.

PCS is the same as GSM , but it is not in the 800/900MHz band, it is at 1800/1900MHz. It is nothing like CDMA at all.

Andy (an Electronics Engineer who does not work for Nokia)
12-31-2004 Over year old.
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helimodels
Senior Heliman
Location: Dublin, Ireland

My Posts This: Topic  Forum		Years ago when first had a mobile I tried and failed to get any adverse effect even in the extreme cases of being right on top of Tx & Rx, ringing in & out. Have been happy to plough on ever since, but no plans for a synthesised Tx. But let's see, what if the nearby cell tower goes down, and now your mobile has to really pump it out…

Once you believe the statements here, it's a proven fact that synthesised Tx modules are unfit for use near (the other guy's) mobile phone.

So why the CE mark? Don’t the manufacturers know we all have mobiles? And our friends? And the casual walker-upper?

A design has to be fit for its intended use, and that includes being near a mobile phone, your own or another's. Final.
12-31-2004 Over year old.
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Jinn
Heliman
Location: Taiwan

My Posts This: Topic  Forum		From the reply of Multiplex team for my crash, they say the mobile phone is well known for interference to memory and airplane! But I have never heard one big plane crashed by mobile phone! I think their synthesized Tx certainly fail by contacting mobile phone. I know they use some special cases as an excuse for their technologic weakness! The mobile phone is not so powerful. The electronic devices with processor around us is so many. How many will fail near mobile phone?( I had tested Palm, Pocked PC and some embedded systems). Will a responsible RC manufacturer make a sloopy device as minority? Specialy, as in their instructions, the radio-controlled models are not playithings!
01-11-2005 Over year old.
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z11355
rrMaster
Location: 10000 is enough time wasted.

My Posts This: Topic  Forum		they're German designers. It CAN'T be their fault. All German products
are flawless and perfectly designed.

01-11-2005 Over year old.
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G.Man
rrProfessor
Location: Bristol

My Posts This: Topic  Forum		TBH anyone who has a mobile phone knows what happens when it is in use to their radio in the car, TV at home computer monitor etc etc ad nauseum...

If you are that naive to believe another transmitter of reasonable power that interferes with every other electronic product in the home CE marked or not, WONT have any impact on your computer transmitter then IMHO you should be drinking Evian exclusively...

A mobile phone has no place on the flight line, if nothing else it is a distraction you dont need when in control of a flying meat cleaver...

Keep it in your pit box or car.... dont take unneccesary risks



Don't Email me as I wont reply - PM Only (spam countermeasures)
01-11-2005 Over year old.
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BigChopper
Key Veteran
Location: Cambridge, UK

My Posts This: Topic  Forum
Quote 
If you are that naive to believe another transmitter of reasonable power that interferes with every other electronic product in the home CE marked or not, WONT have any impact on your computer transmitter then IMHO you should be drinking Evian exclusively...


This need not be the case. It IS possible to design something which doesn't suffer from GSM inteference (cheaply!).. like I said before, people/manufacturers use it as an excuse.... interference on your car radio is not in the same safety category as an out of control RC heli.

I agree that you need to leave your phone in your box/car. I don't think Dave ever denied his mistake.. the issue is interference from someone else walking up to you with a phone. It is an easy thing to do by accident, even if you know about the problem..I know I've done it before.
01-11-2005 Over year old.
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Jinn
Heliman
Location: Taiwan

My Posts This: Topic  Forum		In addition, interference on your car radio is also not in the same effect as an out of control RC heli! The radio and computer monitor after mobile phone interference just get some noise into output signal (just blinking and buzz). It never take control of the monitor, i.e., you have never seen some fixed pattern on your monitor. (If it happen, you will hate the monitor). But the Multiplex synthesized one will continuely control your model by mobile phone such that the processor on Rx can not find any nosie in signal and failsafe never work. I don't think this is a general interference effect. It may be a special design that a model controlled by a mobile phone through Multiplex Tx! One day it is may be a good Idea!
01-11-2005 Over year old.
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RotorHead486
Key Veteran
Location: England

My Posts This: Topic  Forum		We have had this issue brought up in our club recently, and the danger is very 'real'!!

There is two schools of thought:

1: To not allow synth Tx's
2: To not allow mobiles on the flight line etc...

The problem being, if someone goes out a buys a new £1500 worth of Synth radio equipment and can't use it, they ain't gona be best chuffed!

Or like Dave said, you can't get away from the fact that someone will just walk over, either a dog walker or a kid or somebody and 99% of these people have mobiles!!

Like Bigchopper said, a 'Grey Area', a huge honking one at that!!!

From what i understand the more reception a mobile phone has the less power it chucks out, and the less reception the phone has the more power it chucks out to look for signal.

Since reading Dave's report i've started leaving my phone in my car or more often turning the thing off, synth or no synth!!

Cheers!
Rotorhead486

One Reason For Crashing'Rogue Servo Bent on World Domination'!!
QuickUK Pilot
01-12-2005 Over year old.
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9387ASH
Elite Veteran
Location: UK

My Posts This: Topic  Forum		Not Heli related ( just yet ), but at home I use both IR Headphones & Radio Headphones, I have a Nokia 6210 and I always know when my mobile is about to go off as I hear the pulsing on my headphones.

I have access to a JR Synth module, so tomorrow I will be checking out its susceptibility to my phone. I will let you know the results as soon as I have tested it.

01-12-2005 Over year old.
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9387ASH
Elite Veteran
Location: UK

My Posts This: Topic  Forum		Well,

I managed to squeeze in a few minutes earlier ( between servicing ) and tested a PCM10X with a Synth module set to CH 73. Using a R800 PCM receiver I couldnt get anything to happen. I the tried with an R549 PPM receiver and same again.... nothing.

As I work in a weak area for mobile phones, I started by turning the mobile off, turned the mobile on to start the search for a node, sent a Text Message with Reports set to on , then set a call up to my home number. Nothing. I will try and set more time to this on Friday. The Synth is the same as the Graupner/JR and if its gone through the German CE marking, then from my previous experience of Teutonic thoroughness, they will have tested it completely !


01-12-2005 Over year old.
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RotorHead486
Key Veteran
Location: England

My Posts This: Topic  Forum		JR!!! You see!!! best in the world!!

Mac_Man: What are the differences between the S649 PCm and the R900 PCM?

Cheers!
Rotorhead486

One Reason For Crashing'Rogue Servo Bent on World Domination'!!
QuickUK Pilot
01-13-2005 Over year old.
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9387ASH
Elite Veteran
Location: UK

My Posts This: Topic  Forum		Very little to be honest, the 900 has gold pins, whereas the 649 has silver.

The Ccty inside hasnt really changed either.

01-13-2005 Over year old.
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Methodical
Heliman
Location: Fairbanks, Alaska

My Posts This: Topic  Forum		just to re-iterate my opinion.

This is most likely to occur in these conditions

A> The phone is not a CDMA phone (verizon, sprint PCS). Needs to be TDMA or GSM, maybe analog will do it as well. most carriers (att and cingular) use GSM.

B> the call is being RECEIVED by the mobile. When a call is sent to a mobile, that mobile pops up and responds will a full-power "im here". When a call is originated from a mobile, all the transmissions are power-throttled.

C> the phone is near the transmitters synth module. RX's may be a bit vulnerable as well, but the range has to be way closer than you'll ever to fly to someone, probably (less than a few feet?)
01-14-2005 Over year old.
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3 pages [ <<    <     1      2     ( 3 )    >    >> ]12631 viewsPOST REPLY
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Main Discussion > Mobile Phone and Synth TX warning
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