ok, so I already know I'm setting myself up to receive the dumbest question ever to be posted, but I gotta ask.
My owners manual states that cell phones should NOT be used inside the vehicle because of the massive amount of electronics the vehicle depends on, and that doing so may very well disrupt said electronics causing the need of servicing. The vehicle is a 1999 RR. This just doesn't sound logical. . . . . but I have to ask.
is this for real ?
Location: Bloomfield, CT If I died today, I lived there all my life.
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Not really such a dumb question. Back in 1999, most cellphones were analog, not digital. Despite being very narrow band, analog RFI (radio frequency interference)is common in other analog circuits. Today, analog cellphones are all but extinct. The chances are pretty slim that even the primitive electronics in a 1999 car will be affected by todays phones.
A rangie friend of mine used to run the RFI lab at Otis elevator. I think they might have worried that evelvators would come slamming to earth when those obnoxious stockbrokers blathered away to impress everyone else in the car.
Correct, it is the RF signal from an analog cell phone that can interfere with many things from reproducing the analog signal in a rhythmic pattern through the speakers of an active system, interfering with other RF signal and also causing damage to the internal workings of electronics. This is the reason why you are asked not to use your cell phone in many emergency rooms. It may mess with some of the electronic devices, heart monitors etc.
Uhm Hello Mom,,,,,, flat line patient....
Digital signal is reproduced in a series of ones and zeros - not an RF sound wave. The receiving device cannot reproduce the ones and zeros thus there is no interference or damage. Not to say the don't have their own damaging qualities but in this scenario there is no problem, particularly in todays technology. (some analog signals still exist, but are fewer)
digital phones still use rf energy to transmit the bianary signal (1's and 0's) and basicly it's the same as analog whats different is the systems at either end (phone and the switch). it affecting anything is very very rare. what started this stuff was in the early 90's someone was on a nextel and the switch screwed up in a c.o. bringing down the phones and they blamed the signal from the phone. i think it was a coincedence and remain skeptical. but thats the story "they" use. i see these signs posted everywhere everyday and everyday i use a cell and so dose everybody else. so far for the last 11 years (since my inception into the feild) nothing has happened do to interference.
hey, thanks for taking me seriously. I had never heard of such a thing, but since it was in the owners manual, and since I'm totally new to Land Rovers... thought I better ask.
well...... actually I have heard of something similar. I work in a hospital and for awhile there were signs everywhere instructing family and visitors not to use cell phones in the units and in the ER... because of the signal interfering with the monitoring equipment. I did some research on that one and found that studies showed that a person would have to be within 1 to 2 feet of the patient / monitor for there to be even a slight chance of interference.
digital phones still use rf energy to transmit the bianary signal (1's and 0's) and basicly it's the same as analog whats different is the systems at either end (phone and the switch). it affecting anything is very very rare. what started this stuff was in the early 90's someone was on a nextel and the switch screwed up in a c.o. bringing down the phones and they blamed the signal from the phone. i think it was a coincedence and remain skeptical. but thats the story "they" use. i see these signs posted everywhere everyday and everyday i use a cell and so dose everybody else. so far for the last 11 years (since my inception into the feild) nothing has happened do to interference.
As a previous Nextel employee of 8 years, Tmobile for one and as a contract employee for ATT then Sprint. I'll agree to disagree. Only beacause they have not completely linked the device and it's signal to damage although the damage occurs. If you place a Nextel phone next to any audio device and the unit receives a signal you will hear the intereference in the speakers. CDMA and TDMA can have the same affect but only on older non shielded devices / speakers. This was much more prevelant 10 years ago but hardly noticable now.
As a previous Nextel employee of 8 years, Tmobile for one and as a contract employee for ATT then Sprint. I'll agree to disagree. Only beacause they have not completely linked the device and it's signal to damage although the damage occurs. If you place a Nextel phone next to any audio device and the unit receives a signal you will hear the intereference in the speakers. CDMA and TDMA can have the same affect but only on older non shielded devices / speakers. This was much more prevelant 10 years ago but hardly noticable now.
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i can see how that would happen on transmit but not recieve. you have to think of it in simpler terms, think of a radio. the signal is in the air regargless of weather or not the signal is being cought by a device. just because you turn on a radio and hear music does not mean that magicly the signal goes to the radio as soon as you turn it on, it's always there. same as a phone just because your not standing near any rf sensitive devices when your using your phone the signal is still everywhere. now on transmit that is a different story in that case the closer you are the stronger the energy. oh well some things i'll never get especially their theory on grounding chokes i have yet to find an engineer to explain that to me.(dd2 u might know what i'm talking about depending what side of the industry you were on)
It is not the issue of analog vs digital per see, it is one of RF power, frequency and harmonics. However the oldest analog phones put out up to 3W of RF power vs something like the 600-800mW power of current handleld digital phones (The Nextel guy can probably give the exact number)
Back when auto electronics were newer, the car makers put all kinds of disclaimers on use of RF devices in vehicles. Most were unfounded, but some were real.
The real culprit are high powered ham rigs or CB's with big linears. They can transmitt a "near field" signal that is so strong that it can swamp the input of sensors and other items that feed digital systems.
There are other sources of RF noise that can screw up systems. As an example, I had one car where the bimetallic directional flasher wore out. In addtion to the directionals not working, the arching on blinker acted like a Marconi-spark gap transmitter and screwed withe the ABS sensor input.
Whenever I switched on the directional, I would lose my brakes because the ABS thought I had wheel slippage and pushed back my brake pedal. I put in a new flasher and all was fine.
This simple thing could have caused a fatal accident. For this reason, car makers are gun-shy of approvals of any RF device.
Cell phones are now so common that they can't avoid them, but you will also notice that they don't mention them now either.
A garage door remote can cause issues or a radar detector even the electric door sensors at the grocery store.
In the dish sat biz it is common for people to have a problem with their set top boxes because the radar detector in their car sends signal is through the LNB of the dish and back to the box and bam, it needs to be reset to decode the signal from the satellite.
Not RF I know, but an example of signal interference.
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maybe the dumbest question in here. . . .
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