Effects of MDs on Storage Media?

Bucket Lister

Bronze Member
Dec 20, 2023
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Detector(s) used
XP Dēus II
XP MI-6
XP WSA II-XL
Primary Interest:
Metal Detecting
Got into a discussion about finding lost items, and could a metal detector find things like flash drives, SSDs, micro SSDs, etc. No problem as long as there's some metal on them. But what about any data? I tried searching, but most articles were talking about walk-through metal detectors, and said don't take your laptop through one.

So what about "our" metal detectors (yeah, same basic tech)? If we locate someone's lost flash drive, micro SSD card, etc. is there risk of wiping out their data? :dontknow:
 

Upvote 2
I wouldn't think there would be any risk. I mean, metal detectors aren't emitting magnetic fields, they're emitting radio waves. The air on this planet is full of radio waves all the time, and USB drives don't erase themselves. Wifi, cell towers, AM/FM/Shortwave and other radio bands, broadcast TV bands, satellite and down links, microwave transmissions, and so forth. I don't see how the relatively weak RF emitted by a metal detector is going to do any damage when none of those other things do.
 

Yeah, iv taken the odd picture of something on a detector coil with my phone whilst the detector was still on and the phone would have been just 6 or 7 inches away. It never entered my mind if it would be a problem because I never thought about it, but it seems not to be after reading this.
 

I have found several micro ssd cards, mostly in parks where the homeless tend to gather.Those who say no, put your coil closer to the ground.
 

I wouldn't think there would be any risk. I mean, metal detectors aren't emitting magnetic fields, they're emitting radio waves.
What are radio waves, but a type of electromagnetic radiation?

I have found several micro ssd cards, mostly in parks where the homeless tend to gather.Those who say no, put your coil closer to the ground.
Please clarify. Are you saying a MD can/will wipe a micro ssd card?
 

Sorry I miss red the OP question, as he stated finding the ssd card, then wiping it. No it will not wipe it, only FIND it.
Thanks.

I just don't want to have to tell someone, "I can find your ssd card, but it'll wipe out any data."

Something like that wouldn't make recovery worthwhile.
 

I mean, metal detectors aren't emitting magnetic fields, they're emitting radio waves.
Sorry, that is exactly backwards. Metal detectors do not emit radio waves (to any significance), but they do emit a fairly strong magnetic field.

Whether it's strong enough to damage magnetic media I don't know. I've carried my laptop through a walk-through security a number of times with no ill effect but it has an SSD, which stores data using an electric field effect instead of a magnetic field effect. As do flash drives and SD cards. But even electric field effect storage can be altered by a strong and fast changing magnetic field, such as with a PI detector. I just don't know how strong it would have to be. You can easily test it by putting some files on a flash drive, set it on a metal detector coil for a few seconds, and then see if files survive.
 

Sorry, that is exactly backwards. Metal detectors do not emit radio waves (to any significance), but they do emit a fairly strong magnetic field.
I stand corrected.

For the benefit of anyone else laboring under the same misconception that I was, here's an explanation. I had always thought that metal detectors emit RF, since they operate either on single frequency, or multi-frequency (and since they are so easily interfered with by other sources of RF). Frequency is something that radio waves are measured in, not magnetic fields. But... for metal detectors, frequency isn't referring to the oscillation of a radio wave, it's referring to the oscillation of a magnetic field by the reversing of direction of current flow in the detector's coil. More info here.

Today I have learned. :icon_thumleft:
 

I stand corrected.

For the benefit of anyone else laboring under the same misconception that I was, here's an explanation. I had always thought that metal detectors emit RF, since they operate either on single frequency, or multi-frequency (and since they are so easily interfered with by other sources of RF). Frequency is something that radio waves are measured in, not magnetic fields. But... for metal detectors, frequency isn't referring to the oscillation of a radio wave, it's referring to the oscillation of a magnetic field by the reversing of direction of current flow in the detector's coil. More info here.

Today I have learned. :icon_thumleft:
Wireless detectors, like Dēus II, DO emit RF. That's how the components communicate with each other.
A search coil, a remote control and headphones (+ optional pinpointer). All three components communicate with each other over lightning fast digital radio signal.

It's got quite a range, too. Often I've had to go back to my car for something, or inside to use the restroom, and (I leave my headphones on) I can still hear the signal from 100 feet away.
 

I mean, metal detectors aren't emitting magnetic fields, they're emitting radio waves.


Actually, they emit both.

Every frequency has both an electric field (far field) and a magnetic field (near field). Metal detectors operate within the magnetic field.

Google "magnetic field vs. electric field" and you'll get plenty of info. BTW, it's all Maxwell's fault.. :laughing7:
 

Actually, they emit both.
I figured. IDK how these things work yet, but since it seems to be able to tell the difference between ferrous & non-ferrous reasonably accurately, I thought there must be some kind of magnetic field involved, BICBW.

This has been a really interesting (for me, anyway) discussion--thanks to all. I don't feel confident there's a definitive answer--or even a consensus--so I think I'll stick with telling folk (for now), "I may be able to find it for you, but I can't guarantee the integrity of the data."

It could have been corrupted anyway, but I'd rather be honest & transparent. :laughing7:
 

In theory, most of electronic equipment and data media is suseptable to changeing magnetic field. In reality, most of short term exposuers to commercial VLFs and most of PIs does not harm data in storage media or electronics circuits. However, high energetic deep seeking PIs will and does. I use to have a PI with polarisation power of 700 W, managed to kill a laptop computer and a few cell phones with it.
 

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