Passenger use of GPS
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PAXboy: For all intents & purposes, on board a passenger aircraft the "inertness" of a GPS receiver can pretty much be relied upon, as the IF level possibly radiated by the antenna is not only at a miniscule level (compared to say digital broadcast towers spewing out harmonics everywhere that the aircraft navigates over with no problem whatsoever), but at a frequency that goes nowhere near instrumentation/navigation receive frequencies. 
I think the main reason that many airlines don't want you using your GPS on board, is that they have no control over whether the unit has been modified, or is still in spec.
I have used a GPS receiver on SAS, Swiss, and Cathay after consulting the CC. No US airline (that I have asked) has allowed me, nor Qantas or BA.
I think the main reason that many airlines don't want you using your GPS on board, is that they have no control over whether the unit has been modified, or is still in spec.
I have used a GPS receiver on SAS, Swiss, and Cathay after consulting the CC. No US airline (that I have asked) has allowed me, nor Qantas or BA.
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Passenger use of GPS
I've used a laptop with Oziexplorer and USB Pharos GPS (got it with Microsoft Streets and Trips) and generally have good reception with the GPS stuck to the window. In moving map mode got altitude, GS etc
I travel mainly in Canada and have asked CC in both Westjet and Air Canada - in both cases they went and checked with flight crew and got permission no problem.
I travel mainly in Canada and have asked CC in both Westjet and Air Canada - in both cases they went and checked with flight crew and got permission no problem.
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10W & Pax Vobiscum
Referring back to your gps read out. 697mph is a typical figure for Eastbound flights in a jetstream, I have made many flights from Zurich to Bangkok with the indicator pegged on 1111kph (690mph). Needless to say it doesn't work the other way!
Referring back to your gps read out. 697mph is a typical figure for Eastbound flights in a jetstream, I have made many flights from Zurich to Bangkok with the indicator pegged on 1111kph (690mph). Needless to say it doesn't work the other way!
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Assuming a cruising speed of Mach 0.83, that equates to (counts on fingers) a 150mph tailwind.
Mach No. depends on Outside Air Temperature and hence Air Speed varies with Mach at different temperatures. Some jet streams can have speeds of 250-300kts.
I know flights comeing across the pond to the UK slow their airspeed right down as yes it would be nice to land early but they would not have a gate to go to.
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To summarise that thread, if the GPS is a receiver only, then it's ok to have it on at all times (incuding during take-off and landing) (despite what it says on the Qantas website about GPS systems). But of course, it is up to the Captain of the flight as he/she will have the ultimate say.
Thread Starter
mingalababya
...thanks, what a terrific thread ! Haven't been all through it yet. Didn't see any mention of reference ellipsoid either, surprising as I thought that's how gps goes from earth centic cartesian to map + height.
Some of these threads can get surprisingly energetic: begining to wonder why some std pax abuse isn't included with the initial formalities ('..will you clowns please pay attention, even those of you who can't read and paid a stupidly small price for the service we provide..')
Some of these threads can get surprisingly energetic: begining to wonder why some std pax abuse isn't included with the initial formalities ('..will you clowns please pay attention, even those of you who can't read and paid a stupidly small price for the service we provide..')
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barstow,
What about local oscillator radiation? There's not just the IF to consider - which itself can be a pretty big signal at the detector, as well as the radiation from the digital processing stages. That will depend more on the level of integration and the CMOS geometry used - to some extent, the geometry defines the supply voltage and thus the logic voltage swing. Very small geometries mean low voltage, but in complex circuits, leakage currents can be big enough to make a larger geometry more attractive.
A lot depends how the particular device is classed by the manufacturer under the EMC Directive: portable broadcast receivers have no limts (EN55013), while car radios have to meet -57dBm below 1GHz and -47dBm above. Those limits apply to general receiver radiation too, to meet Eu requirements. (ERC REC 74-01, implemented in all ETSI Standards -that will apply generally to cellphones). The US is somewhat less stringent. (CFR47 Part 15). If a Chinese make, the CE mark may just mean 'Chinese Export', with no attempt at meeting any EMC or spurious emission limits. Or it may be very good.
What about local oscillator radiation? There's not just the IF to consider - which itself can be a pretty big signal at the detector, as well as the radiation from the digital processing stages. That will depend more on the level of integration and the CMOS geometry used - to some extent, the geometry defines the supply voltage and thus the logic voltage swing. Very small geometries mean low voltage, but in complex circuits, leakage currents can be big enough to make a larger geometry more attractive.
A lot depends how the particular device is classed by the manufacturer under the EMC Directive: portable broadcast receivers have no limts (EN55013), while car radios have to meet -57dBm below 1GHz and -47dBm above. Those limits apply to general receiver radiation too, to meet Eu requirements. (ERC REC 74-01, implemented in all ETSI Standards -that will apply generally to cellphones). The US is somewhat less stringent. (CFR47 Part 15). If a Chinese make, the CE mark may just mean 'Chinese Export', with no attempt at meeting any EMC or spurious emission limits. Or it may be very good.
10DowningSt
Why, I wonder. They are electronically inert, as someone has pointed out. In other words they represent no more risk to aircraft safety than a Biro pen, and perhaps less than an Ipod.
I have personal experience with a Garmin 100 used in a Cessna 310 which would prevent communication on HF as long as the Garmin was turned on.
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Took a long time to catch up on that one, didn't it?
Not many Cessna 310s with HF comms these days, and even more surprising that a Garmin GPS would prevent the use of it. We live and learn, don't we.
Not many Cessna 310s with HF comms these days, and even more surprising that a Garmin GPS would prevent the use of it. We live and learn, don't we.
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Maybe we can solve this once and for all?
Certainly Virgin, perhaps other carriers allow you to have handhelds operational if in Flightsafe mode.
Blackberry Pearl with cell tx/rx off (Flightsafe) GPS function still works.
Turn it on, hold it to the window and go "AAaaahhhh..." as it displays a speed of 550+MPH in the cruise and loads a nice little map showing you just where you are.
Certainly Virgin, perhaps other carriers allow you to have handhelds operational if in Flightsafe mode.
Blackberry Pearl with cell tx/rx off (Flightsafe) GPS function still works.
Turn it on, hold it to the window and go "AAaaahhhh..." as it displays a speed of 550+MPH in the cruise and loads a nice little map showing you just where you are.
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I used my Garmin 96 on a Ryanair from PIK-STN last week and it worked fine, didn't need to "press it against the window" to get a proper signal but picked up more satellites if it was close to the window,
Pretty much good fun and a good way to wile away the trip. My readout was 455kts and pilot said we'd be flying at 37000ft and readout was 37263ft, due to flying flight levels and pressure varience. All good fun, I'd recommend it.
Pretty much good fun and a good way to wile away the trip. My readout was 455kts and pilot said we'd be flying at 37000ft and readout was 37263ft, due to flying flight levels and pressure varience. All good fun, I'd recommend it.
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I have personal experience with a Garmin 100 used in a Cessna 310 which would prevent communication on HF as long as the Garmin was turned on.
All the Garmin 100's I've used were specifically designed aviation dashboard-mounted GPS units.
Not many Cessna 310s with HF comms these days,
Cheers,
DIVOSH!
Thread Starter
I originally wanted to know this because....
flying from Luton to the IoM I think the a/c moreorless flies over my house and I wanted to know when and which way to look. Hadn't figured on a global response. One thing that may be relevant is that there is always the possibility of modified gear. So whereas shop-bought stuff should be OK, perhaps chipped equipment is untested and unknown.
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I have used both my Garmin hand held a/c GPS as well as the Nuvi for my car (in off-road mode) during flights and both have worked well albeit after a little while to acquire satellites. I did this in plain view of CC with no problem.
