stagecoachco
Line Up and Wait
http://news.yahoo.com/video/tech-15749651/danger-of-cell-phones-during-takeoff-and-landing-25523758
Not sure I believe it or not.
Not sure I believe it or not.
The US FAA is waiting for Boeing to issue a service bulletin to address Wi-Fi interference with Honeywell Phase 3 display units (DUs) before deciding if regulatory action is required.
"We're aware of the impending service bulletin. Once we get it, we'll determine if we need to take some regulatory safety action," said an FAA spokesman.
The rule to turn off all electronic items preceded the invention of cellular by several decades.Wasn't the initial reason to turn off electronics like cell phones strictly due to an FCC requirement?
The rule to turn off all electronic items preceded the invention of cellular by several decades.
But there is indeed a rule by the FCC. Part 22 to be exact that states that cellphone in the 800MHz band cannot be used in flight. There is no FCC rule for cellphones in any other band. For example those that operate in the 1900MHz are regulated under Part 24 and no mention is made of operations in flight. In fact little is mentioned in Part 24 that is applicable to the technology itself.
Agreed. I can almost always tell when my student has his cell phone still on in his/her flight bag or pocket. I get a "buzz" in my ANR headset that is very recognizable just before a call is received. I can also hear a similar kind of noise in my headset when the ASR-9 or 11 radar sweeps past me while taxiing. All of these signals are noticable, but do electronic devices interrupt communications or navigation? Evidently Boeing thinks that it does...and maybe there's some truth to that.
What types of cell phones operate on the 800 MHz band versus the 1900 MHz? One 3G/4G while other isnt?
Nope not so simple.What types of cell phones operate on the 800 MHz band versus the 1900 MHz? One 3G/4G while other isnt?
I can hear the buzz from my GSM phone if I forget to turn it off. I can also hear it in my computer if I lay the phone down next to it.I've never once heard my Verison (CDMA network) phone make noise in the comm's. However, when I fly with people who I know have GSM phones, I can hear them all the time.
Hmm.... Is it that hard to block electronic signals from interfering with those "sensitive electronic sensors hidden in the cabin" ?
Ghery will be along soon to clue us all into the real nitty gritty world of EMC.In general, electromagnetic compatibility is not a simple task.
http://forums.aopa.org/showthread.php?t=74141
Ghery will be along soon to clue us all into the real nitty gritty world of EMC.
Despite the fact that 20 years of testing still hasn't definitively proved that cell phones, let alone any other electronic device, can cause aircraft interference, passengers are still prohibited from using tablets and e-readers during takeoff and landing.
This was probably a phone using LTE. Lots of wideband noise. Really bad stuff too. 10-20MHz away with a rejection limit of -40dBm/MHz interference victims can be 10-20m away from the agressor transmitters.Well, CNN doesn't know all the facts. No surprise there.
I had a conversation with the chief scientist on EMC matters at the FAA earlier this year at an IEEE EMC Society Chapter meetings in Seattle. Dave told me about a recent case where Garmin was testing a new piece of avionics that included GPS. They were using a mobile phone and it appeared to be interfering with the GPS receiver. This is not anecdotal, this is verified fact - they took the hardware involved (product and phone) to the lab and duplicated the problem. The phone had a spurious emission from its power amplifier right in the GPS band. Every example of that model phone that they got their hands on did exactly the same thing. This isn't an "I heard it from a friend who heard it from his barber" type story. This is verified by people working on the hardware.
Needless to say, I still have concerns about transmitting devices being used on board aircraft. WiFi seems to be OK in that we had the old Connextions (sp?) by Boeing product and now airlines are fielding their own WiFi products on aircraft. But, they still prohibit use during taxi, take-off and landing. Looked at the tablets lately? My Google Nexus 7 only has WiFi, but it also has a GPS receiver. Some would argue that that receiver could be a problem, but my comeback to that is that it works, so if it isn't interfering with itself there's a better than even chance that it won't interfere with another GPS receiver. Other tablets also have radios in the mobile phone bands. We've already seen one mobile phone that tanks a nearly GPS receiver, so there's a potential problem there.
The jury is still out on this. I just saw on-line where the head of the FCC is talking to the FAA saying that the ban doesn't make sense. I think he needs to cool his jets a bit and stick to what he knows about. He is a lawyer, so it isn't EMC.
This was probably a phone using LTE. Lots of wideband noise. Really bad stuff too. 10-20MHz away with a rejection limit of -40dBm/MHz interference victims can be 10-20m away from the agressor transmitters.
I just saw on-line where the head of the FCC is talking to the FAA saying that the ban doesn't make sense. I think he needs to cool his jets a bit and stick to what he knows about. He is a lawyer, so it isn't EMC.
Noting that FAA rules have been too slow to change in the past, McCaskill's letter suggested that if the FAA does not act on this issue in a timely manner she is "prepared to pursue legislative solutions."
If portable electronic devices were much of a problem we would have seen evidence by now. Do you seriously think everyone has them turned off?
A couple of decades ago when I carried a pocket pager, that little devil radiated enough RF to break the squelch on the scanner and on the 2 meter radio I had in my ham radio shack. For months I kept thinking there was a phantom signal in my neighborhood. OF course it was on my belt and only bothered the radios when I sat down at the electronics bench.
In the early days of GPS my COM radio (King) would cause the GPS to lock up when the COM radio was set on certain frequencies. I don't remember which they were and a search should show it up (too lazy to do it myself)
What would happen is the IF oscillators in the receiver would mix together and heterodyne to a frequency that was close to the GPS frequency and that signal would radiate backwards through the amplifier stages and onto the COM antenna. Even though this signal leakage was low power it was of course vastly stronger than the weak satellite signal.
Same deal with any device that has internal RF oscillators - and this includes anything with a CPU in it, PC, tablet, pager, phone, digital camera, etc.
For those of you with no background in electronics do some reading on superheterodyne.
I have a similar issue today with my Garmin 196 in my pickup (2006 Chevy Silverado) - anytime the factory radio is in the AM band the GPS loses all it's satellite locks. 100% correlated. Step out of the truck more than about 15 feet and I get sat signals back. Change the radio to FM or XM and I get sat signals back. The sat signals are still there of course - it's just that the signal to noise ratio completely washes them out.