Coil Kills GPS?

Hi all,
While searching YouTube and watching several videos: I’m wondering if someone could confirm that a coil can stuff up a GPS, to the extent that the GPS’s memory could be wiped or even worse the GPS die.
If this has already been discussed in another thread please could you let me know where?

Thank you

I cannot say that it couldn't happen but it is very very unlikely although pulse detectors have a very intense field in close to the coil say within several inches maybe. These pulse could possibly fire up some significant stray voltages within the GPS which might screw some of the memory chips.

GPS memory is not magnetic field related and GPS operate at a very much higher frequency than what your detector operates at.

Every body uses their Tom Tom in the car to no ill effect and the inside of most cars is packed with magnetic fields (when the motor is running)somewhat stronger than what any hobby metal detector pumps out.

The magnetic field ( low frequency) in my Corrolla is up around 45 milligauss which I might add, is well into what is concidered to be a dangerous level (for humans)of low frequency magnetic radiation.

Yes it happened to me
I did wright this up in a previous post on this forum to warn members.

I did the silly thing of passing my gps too close to the detector coil and it wiped it and couldn't locate anything and was totally usless.
I did send it back in to garmin for repairs and they had to re-flash the processor.
Now it works fine.
If you rely on your gps understand that it will fail if it' gets too close to your detector coil.
Cheers Mark

Never knew that could happen. Will def take more care of the gps when out and about. Would put me up the creek without a paddle if my gps failed as my sense of direction is, well, nothing other than terrible.

Thanks for that piece of info people.

Adrian SS wrote:The magnetic field ( low frequency) in my Corrolla is up around 45 milligause which I might add, is well into what is concidered to be a dangerous level (for humans)of low frequency magnetic radiation.

Whoah! Crikey!! Thats one wealth of information! Adrian SS do you think my car would be the same? Reminds me of when my brother gave me a couple of issues of Nexus magazine (alternative thinker mag) to read back in the 90's, I freaked out!

Thanks for the heads up Mark, can't imagine what it would be like to get stuck without the GPS at the best of times! I get lost even with the GPS, a map and directions.... helps if I turn the Map or use track up function on the Megellan.

Our mates in melbourne have a GPS that Moos like a cow when doing more than the speed limit! Cracks me up because we don't have the audio effects that the city folk have on their GPSs. Our Megellan GPS has all the topo maps on it and best times to fish/hunt the only thing its missing is the points of interests (POI) for GOLD!!!! But I think it would soon start "mooing" if it were in my hands and I could see the POI for GOLD!!!!

Ange,
Am not sure what is causing the field but Imagine it is from the alternator. The field strength is strongest down near my feet. Maybe I should change my socks I would guess that different cars would produce different field strength readings.

The electromagnetic force that you would need to generate to shift the electrons in SD/Flash memory to "wipe it" in GPS receivers, would also be strong enough to rip the iron out of your blood.
Your GPS is basically a radio Receiver, to jam it you would need a transmitter broadcasting louder then the satellites signal being received by your GPS in that area, your detector wont effect you there....

As for MS saying that it happened to them and the company had to "re-flash the processor" I can only assume they meant that the company found an issue with the "Bios Eprom chip" and that a firmware needed to be upgraded onto the chip also known as "bios flashing"

As for the detector some how creating an a higher voltage to the eprom to some out corrupt its data, i can't imagine how this would happen, To erase data from the eprom you would need to subject it to UV light for 15 - 20 minutes and directly on the silicon die.

Anyways in short, No i don't believe your metal detector could "Kill" your GPS unless it's some how producing UV light and an EMP field as large as what you would see in a nuclear device being detonated, if it were you would have more problems to worry about then your GPS dying

Btw i have a Garmin 62S which i clip to the front of my harness and when i find a target i get pretty close to the search coil, No bad effects yet

Cheers Hilly

My GPS unit is a GARMIN GPSMAP 60CSX
The failure was from my detector coil, I used it for months with no problems, passed it over my coil and it instantly failed, remember a PI detector produces a powerfull electromagnetic field which induces a flow of electrons in the nuggets we find at depth so obviously does the same with any close electronic devices.
As I said before be careful it happened to me and I now know of others who stuffed up their GPS units the same way.
I'm no electrinics tech but understand odds , 100 + hrs of normal operation against the ten seconds of the coil coming into close contact and causing failure = 36000 to 1
Don't take my word for it, be my guest give it a go

rarebreed wrote:The electromagnetic force that you would need to generate to shift the electrons in SD/Flash memory to "wipe it" in GPS receivers, would also be strong enough to rip the iron out of your blood.
Your GPS is basically a radio Receiver, to jam it you would need a transmitter broadcasting louder then the satellites signal being received by your GPS in that area, your detector wont effect you there....

As for MS saying that it happened to them and the company had to "re-flash the processor" I can only assume they meant that the company found an issue with the "Bios Eprom chip" and that a firmware needed to be upgraded onto the chip also known as "bios flashing"

As for the detector some how creating an a higher voltage to the eprom to some out corrupt its data, i can't imagine how this would happen, To erase data from the eprom you would need to subject it to UV light for 15 - 20 minutes and directly on the silicon die.

Anyways in short, No i don't believe your metal detector could "Kill" your GPS unless it's some how producing UV light and an EMP field as large as what you would see in a nuclear device being detonated, if it were you would have more problems to worry about then your GPS dying

Btw i have a Garmin 62S which i clip to the front of my harness and when i find a target i get pretty close to the search coil, No bad effects yet

Cheers Hilly

I can only suggest that ya Give Ut A Go and find out for yourself

The field strength at approx 1.5 inches from my Infinium 10 x 14 mono coil is in the region of 100milligauss plus, My meter is maxed out at 100 milligauss and the Inf drives it off the clock.

The Electric field measures approx 500 volts per metre at the same distance.

I am pretty sure that any GPS Satelite signal reaching a handheld GPS is not within an elephants fart of that level.and I feel sure that any GPS device that was passed that close to the coil of the detector would have some very significant voltages generated within any inductive ccts within the GPS and that any excessive current flows produced by those voltages may not be benificial to the GPs unit and its semiconductor componemts.

As far as the magnetic field density around the coil is concerned in relation to being harmfull to humans and other fleshy animals; I believe that there is as yet no hazard levels established but that low frequency magnetic fields of around the 3 milligauss mark do appear to have some effect on cell tissue and possibly rattle our brains a bit.

Hey Adrian SS

Lets look at the evidence, MS said that garmin fixed his gps unit by re-flashing the eprom, so technically speaking no electronics were "damaged" from his detector right ?
So we have 2 possible conclusions from this.
1.) The search coil produced a high enough EMF which the eprom some how conducted voltage from and corrupted the data in the eprom.
2.) It was a coincidence that the data became corrupted in the eprom.

Having this in mind, if the EMF was the cause of the eprom corruption, then walking under high voltage power lines would cause corruptions in pretty much every electronic device that needs eprom chip.

I would suspect that the EMF from high voltage lines would be far worse then a metal detectors ?

Cheers Hilly

Reply with quote

Re: Coil Kills GPS?

New post MS Yesterday at 11:34 pm
My GPS unit is a GARMIN GPSMAP 60CSX
The failure was from my detector coil, I used it for months with no problems, passed it over my coil and it instantly failed, remember a PI detector produces a powerfull electromagnetic field which induces a flow of electrons in the nuggets we find at depth so obviously does the same with any close electronic devices.
As I said before be careful it happened to me and I now know of others who stuffed up their GPS units the same way.
I'm no electrinics tech but understand odds , 100 + hrs of normal operation against the ten seconds of the coil coming into close contact and causing failure = 36000 to 1
Don't take my word for it, be my guest give it a go


My question, Why did you pass GPS over coil? thought you would have been more interested in the results of passing coil over soil.

Burnie

burnie wrote: Reply with quote

Re: Coil Kills GPS?

New post MS Yesterday at 11:34 pm
My GPS unit is a GARMIN GPSMAP 60CSX
The failure was from my detector coil, I used it for months with no problems, passed it over my coil and it instantly failed, remember a PI detector produces a powerfull electromagnetic field which induces a flow of electrons in the nuggets we find at depth so obviously does the same with any close electronic devices.
As I said before be careful it happened to me and I now know of others who stuffed up their GPS units the same way.
I'm no electrinics tech but understand odds , 100 + hrs of normal operation against the ten seconds of the coil coming into close contact and causing failure = 36000 to 1
Don't take my word for it, be my guest give it a go


My question, Why did you pass GPS over coil? thought you would have been more interested in the results of passing coil over soil.

Burnie

Hi Burnie
I had the GPS running on a belt clip and was getting interference on my detector , I had a not so bright idea it could be from the GPS so without thinking just took it off the clip and passed it over my running detector coil, the interference was due to bad weather ,the stuffed GPS was my stupidity.
Cheers Mark

rarebreed wrote:Hey Adrian SS

Lets look at the evidence, MS said that garmin fixed his gps unit by re-flashing the eprom, so technically speaking no electronics were "damaged" from his detector right ?
So we have 2 possible conclusions from this.
1.) The search coil produced a high enough EMF which the eprom some how conducted voltage from and corrupted the data in the eprom.
2.) It was a coincidence that the data became corrupted in the eprom.

Having this in mind, if the EMF was the cause of the eprom corruption, then walking under high voltage power lines would cause corruptions in pretty much every electronic device that needs eprom chip.

I would suspect that the EMF from high voltage lines would be far worse then a metal detectors ?

Cheers Hilly

Well now, that all sounds like reasonable logic , even ta me

Maybe it was just a fluke that the GPS sh...t itself at that particular moment but in any case now I am going to have to go out and take some magnetic field strength and voltage density readings beneath HV power lines and by HV I mean above 66,000 volts 50 hz.

The magnetic field strength at ground level beneath these power lines is not going to be very high so the inductive ability will also not be high; The volts per metre might be up a bit, depending on atmospheric conditions although I doubt that an electric field would be as damaging as an dense VLF AC magnetic field.

Anyhoo it will be intersting to find out.

Well I think it is feasible for a device to lose its memory when it is subjected to pulses from a PI coil. It would be fairly easy for voltages to be induced in to the tracks on the cct board which can then cause a glitch to occurr. This can happen with glitches on the power rails causing the processor to skip an instruction or any number of random outcomes. It could also cause glitches with the microprocessor sending and retrieving data from the eeprom. Eeproms these days are electronically programmable and erasable.

I work on tractors and have seen a number of times when processors loose their memory because of a bad diode in an alternator causing excessive ripple on the power rails. I see this as being no different.

Cheers Mick

Let us know how it goes Adrian SS, I'd be interested to see the outcome on your tests

Cheers

OK Mark fair enough I wasn't doubting your claim, just having a dig

Burnie

rarebreed wrote:Let us know how it goes Adrian SS, I'd be interested to see the outcome on your tests

Cheers

This is what I discovered this morning.

Weather.... Cold, Cloudy, Windy, Damp from recent rain.
Time 10:00AM

Standing directly beneath a 132kv distribution line:

1. 50 hz magnetic field Strength.......2.9 milligauss
2. 50hz electric Field density............450 volts per mtr


Standing 35 mtrs to the side of the transmission line:

1. 50hz magnetic field Strength.......0.6 milligauss
2. 50hz Electric Field density..........25 volts per mtr.

This is as I suspected the results to be and I would not want to be living directly beneath this tramission line.
I doubt that these levels would be of any trouble to a GPS but could definately upset some metal detectors.

These readings would vary with on load and atmospheric conditions and would also be proportionally higher if taken beneath 330kv and 500kv Transmission lines..

I used two meters to cross check the readings; One meter reading the field strengths in three directions and the other meter reading in one direction only, this meter indicates the strongest signal when pointing directly at the sourse. Both meters gave close enough to the same readings.

And a bit of useless drivel for those interested in working out how the above figures relate to some every day situations.

For those concerned with low-frequency electromagnetic radiation in the home, the following conversions are needed most:

1000 nT (nanotesla) = 1 µT (microtesla) = 10 mG (milligauss)
1,000,000 µT = 1 T

• 31 µT (3.1×10⁻⁵ T) - strength of Earth's magnetic field at 0° latitude (on the equator)
  
• 5 mT - the strength of a typical refrigerator magnet
  
• 1.25 T - magnetic field intensity at the surface of a neodymium magnet
  
• 1 T to 2.4 T - coil gap of a typical loudspeaker magnet
  
• 1.5 T to 3 T - strength of medical magnetic resonance imaging systems in practice, experimentally up to 9.4 T
  

Power lines can and do affect GPS signals through multipath interference. As surveyors we try to set up our RTK equipment as far as possible from power lines for this reason. The receivers will still operate but the accuracy can be affected. This does not matter so much for a Garmin as it is only reading the code of one broadcast, whereas survey equipment relies on more than one signal from the satellites plus reads the carrier phase as well.

As for a detector coil wiping out the memory of a handheld I can only assume that this has happened to something else in the electronics other than the receiver itself. My knowledge does not extend that far unfortunately. I can ask a doctor at the uni I attend, he knows a cartload about it, plus a bloke I work with who was one of the first surveyors to use GNSS and has been using them for 25 years might know something too. I will definitely be keeping it in mind, I would hate a detector coil to wipe the data off one of our controllers or base receivers. Cheers!

I have yet to have any dramas with my garmin GPS. Interesting topic indeed......

Not quite what you are talking about here but I was trying to
talk to someone on my 2 way radio and they couldn't hear me.
I could hear them clear as day. I turned my detector off and hey presto, they could
hear me clear as a bell.

Normally I just communicate with my wife and she's usually near by and we have
no problem.This was to a car going down the road a bit further away.

Alan