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Post by ironhold on Dec 29, 2014 18:52:44 GMT
Yes, even a show like this one has actual scientific issues to be examined. AG171 / "Pokemon Ranger: Deoxys Crisis pt. 1 (original US air date 28 October, 2006) The characters have entered a region which is experiencing unusual levels of electromagnetic interference. This interference is so bad that electronic devices are malfunctioning and a flock of birds is shown as being unable to navigate without human assistance. One of the characters, a ranger named Solana, is somehow still able to use her rescue equipment in spite of the interference. In the original Japanese dub (if Bulbapedia is accurate), she explains that her equipment is shielded from EM field interference. In the English dub produced by 4Kids!, however, if I heard the episode right she explains that her equipment is hermetically sealed, which should only protect it from gasses and small particles. So - Can a hermetic seal around electronics also protect against EM interference? If so, then how does it compare to normal EM shielding? (I'm guessing that 4Kids! simply botched the dub again, but this time around they did raise an issue which does touch on science. I don't see anything as to whether or not any other foreign dub repeated this mistake, so this was likely localized. Given that the anime is as internationally known as the franchise itself is, there shouldn't be any issue with doing this myth in an episode unless Mythbusters is somehow broadcast in Saudi Arabia [which has an active ban on the Pokemon franchise].)
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Post by wvengineer on Dec 30, 2014 2:44:41 GMT
To start off, a hermetic seal is a airtight seal on a container. So the question is how is the seal made? A metal container would make a good Faraday cage and EMI (Electromagnetic Interference). If plastic, it would depend on the container. Most plastics are non-conductive and would not protect from EMI, but some are. Another option is to line the inside of the case with foil. This is very common with most modern small transmitters like cellphones and handheld two-way radios. They make plenty of models that are air, dust, and water sealed.
So without knowing more about the devices, it's really impossible to say.
In short hermetic seal =/= EMI shield and vice versa. Some electronics are EMI shielded without being hermetically sealed and some are. Purely depends on the design of the device.
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Post by the light works on Dec 30, 2014 2:48:34 GMT
my question is whether EM shielding would be of any benefit for navigational gear - or to be more precise, would the EM interference be able to be so specific that it would only interfere with the operation of an unshielded piece of equipment and not interfere with whatever external signals it uses for navigation?
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Post by wvengineer on Dec 30, 2014 16:49:28 GMT
What is the equipment in question? In a high EMI area, the usefulness of a device will depend on the function. Just some random examples: A DVD player would work fine if it is properly shielded. Where as a GPS,would not even if shielded. The GPS relies signals from outside to calculate position. If interference is strong enough to overwhelm the GPS signals, then it doesn't matter how well shielded it is, it won't be able to pick up a signal to work off of.
The question is how broadband is the interference and what signals are you trying to get?
You can have navigation devices that work of a compass and accelerometers to map a course, but they are not nearly as accurate or reliable.
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Post by ironhold on Dec 30, 2014 22:53:20 GMT
The inoperable items were an assortment of what would be considered "civilian-grade" in that universe, such as a GPS system, a palm pilot knock-off (which stores data on the region's wildlife for use as a quick-reference guide), and some other gadgets.
The operable items are an assortment of "specially made for public servants" items like a communications headset.
As far as the interference itself goes, the characters discover that the source is a meteorite which is acting as a lodestone due to a recent round of sunspot activity. IIRC, the activity begins to subside when the meteorite is destroyed.
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Post by the light works on Dec 31, 2014 1:26:38 GMT
The inoperable items were an assortment of what would be considered "civilian-grade" in that universe, such as a GPS system, a palm pilot knock-off (which stores data on the region's wildlife for use as a quick-reference guide), and some other gadgets. The operable items are an assortment of "specially made for public servants" items like a communications headset. As far as the interference itself goes, the characters discover that the source is a meteorite which is acting as a lodestone due to a recent round of sunspot activity. IIRC, the activity begins to subside when the meteorite is destroyed. so, in short, the shielded items would function, but might or might not get a usable signal.
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Post by wvengineer on Dec 31, 2014 1:57:40 GMT
Modern small electronic computers like smart phones and tablets actually are built to be shielded for various reasons. The biggest is that the small electronics can be susceptible to EMI so shielded cases provide better reliability. In cell phones, being tht they generate EM radio waves, they need a bit more because of that.
So looking at the list:
1. GPS, wouldn't work due to not being able to get a signal. May or may not be sheilded. 2. Palm pilot. Would likely already be shielded and would probably work as long as it was using internal memory. 3. Comm headset. Would be sheilded but would not work due signal being jammed.
As far as the meteorite acting like a loadstone due to solar activity, that bit is completely bogus.
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Post by ironhold on Dec 31, 2014 2:14:41 GMT
Thing is, the headset is shown getting perfect signal no matter what is happening.
EM radiation. Space alien. Explosion. Nothing kills the signal.
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Post by silverdragon on Dec 31, 2014 11:19:37 GMT
How do you "seal" an electronic gadget that needs cooling. Especially if it relies on air cooling....
I ask as I am having this conversation elsewhere, in a slight different nature, on how to seal up a camera for underwater work....
So far, the "Duh!" moment came with the fact the container was in contact with Water.... water cooled....
EM shielding, some electronics now come with EM shielding in place.
On what you just said, Space alien, wouldnt they just take out the satellite broadcasting the signal?... Radio waves may be interrupted by an EM pulse. Will they be killed?... depends on the decay rate of the pulse, and how much gets as far as the broadcast aerial. If the signal is stopped, doesnt matter how much you shield your equipment, you wont get a signal.
Also....
I spot a huge flaw.
How the heck do you protect equipment that is dependant on outside signals?... See that big aerial you have to receive signals?.. it goina get FRIED fool?..... (Even if its only the size of a mobile phone aerial ... its still an aerial... it still getting signals...)
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Post by the light works on Dec 31, 2014 14:27:30 GMT
How do you "seal" an electronic gadget that needs cooling. Especially if it relies on air cooling.... I ask as I am having this conversation elsewhere, in a slight different nature, on how to seal up a camera for underwater work.... So far, the "Duh!" moment came with the fact the container was in contact with Water.... water cooled.... EM shielding, some electronics now come with EM shielding in place. On what you just said, Space alien, wouldnt they just take out the satellite broadcasting the signal?... Radio waves may be interrupted by an EM pulse. Will they be killed?... depends on the decay rate of the pulse, and how much gets as far as the broadcast aerial. If the signal is stopped, doesnt matter how much you shield your equipment, you wont get a signal. Also.... I spot a huge flaw. How the heck do you protect equipment that is dependant on outside signals?... See that big aerial you have to receive signals?.. it goina get FRIED fool?..... (Even if its only the size of a mobile phone aerial ... its still an aerial... it still getting signals...) cooling a hermetically sealed device is easy - you just put the heat sink outside the seal. (or more specifically, you make the heat sink part of the sealed enclosure)
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Post by silverdragon on Dec 31, 2014 14:42:31 GMT
Putting the heat-sink outside of the seal... you have to seal around the heatsink. Thats quite different from putting the thing in either a snapllock container or a sealed plastic bag, it involves making a seal around something quite often metal, not easy to "glue" to, or to get off again when you finish the project.
"Budget" bodges dont come easy......
This is one reason why I am now playing with a Raspberry PI. Its a small computer that doesnt give off a lot of heat and can be sealed up for a certain length of time in a small space with no extra airflow needed.....
All we need now is to work on the "Window" for the camera. The thick plastic has been glued to a glass window and is air-tight, now we need to experiment to see what depth we can get..... And we have to work on the dummy load and flotation balance to get neutral.
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Post by the light works on Dec 31, 2014 14:56:33 GMT
Putting the heat-sink outside of the seal... you have to seal around the heatsink. Thats quite different from putting the thing in either a snapllock container or a sealed plastic bag, it involves making a seal around something quite often metal, not easy to "glue" to, or to get off again when you finish the project. "Budget" bodges dont come easy...... This is one reason why I am now playing with a Raspberry PI. Its a small computer that doesnt give off a lot of heat and can be sealed up for a certain length of time in a small space with no extra airflow needed..... All we need now is to work on the "Window" for the camera. The thick plastic has been glued to a glass window and is air-tight, now we need to experiment to see what depth we can get..... And we have to work on the dummy load and flotation balance to get neutral. so once again you are looking for a way to do something without using any of the bits and bobs that were designed to do what you want. Like, say, an underwater camera. www.scuba.com/scuba-gear/Underwater-Camera.html
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Post by silverdragon on Dec 31, 2014 15:11:57 GMT
And what use is all of that website?.... All of us in the project already own DSLR camera's that were the price of owning and running a decent car when new. Do we now wish to pay again for a completely new and different camera? One that may not be as good as what we already have, just works underwater.....
No.
But do we want to sacrifice our own DSLR?....
Again no.
But do we have the technology to put our camera into a thick safe waterproof environment to be able to do some underwater photography?.... Yes, yes we do, and why not?.
One thousand dollars just for your camera..... (on that web site...) we intend to spend half that on a rig that will support MULTIPLE camera's, and be fully remote control.... As in, we are cannibalising a R/C Submarine. It will send Video back over a Wi/Fi network, hence this Raspberry PI I am playing on, and with a bit of luck, also send instant copies of the photographs taken back as well, via most camera's ability to plug in to USB.
Yeah, sure, I can pay thousands for a submersible.
But what fun is that?.. Buying the thing ready built out of the box?... What final satisfaction, compared to something a team builds.
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Post by the light works on Dec 31, 2014 15:17:42 GMT
And what use is all of that website?.... All of us in the project already own DSLR camera's that were the price of owning and running a decent car when new. Do we now wish to pay again for a completely new and different camera? One that may not be as good as what we already have, just works underwater..... No. But do we want to sacrifice our own DSLR?.... Again no. But do we have the technology to put our camera into a thick safe waterproof environment to be able to do some underwater photography?.... Yes, yes we do, and why not?. One thousand dollars just for your camera..... (on that web site...) we intend to spend half that on a rig that will support MULTIPLE camera's, and be fully remote control.... As in, we are cannibalising a R/C Submarine. It will send Video back over a Wi/Fi network, hence this Raspberry PI I am playing on, and with a bit of luck, also send instant copies of the photographs taken back as well, via most camera's ability to plug in to USB. Yeah, sure, I can pay thousands for a submersible. But what fun is that?.. Buying the thing ready built out of the box?... What final satisfaction, compared to something a team builds. hey, you do what you want to for a hobby. I mean, I go into burning buildings, who am I to judge. but don't expect me to not point out that if your hobby is reinventing the wheel, you might advertise it as such.
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Post by wvengineer on Dec 31, 2014 22:38:23 GMT
I saw a site a few days ago that carried waterproof cases that were custom fit for various popular DSLR cameras. IIRC, most cases were in the ~$100 USD range. The biggest issue is getting the right case adapter for the lenses you want to use. I'll have to see if I can find it again for you.
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Post by wvengineer on Dec 31, 2014 23:13:42 GMT
Back to the OP, on the headset, where is the signal that it uses coming from? If it is close enough to the transmitter, it could work, but if it is a long way away, then no.
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Post by OziRiS on Jan 1, 2015 4:16:46 GMT
Back to the OP, on the headset, where is the signal that it uses coming from? If it is close enough to the transmitter, it could work, but if it is a long way away, then no. Aren't you all overlooking the issue of frequency here? It's EMI, not EMP, so whether or not there's interference would depend on the frequencies of the equipment used and the frequency range in which there's interference. Had it been EMP (electromagnetic pulse for those who don't know), all unshielded electronics would be fried. But it's not EMP. It's just interference. If the interference is causing birds to be unable to navigate, that suggests the frequency of the interference is extremely low. Birds use the magnetic field of the Earth to navigate and that's only in the 2 kHz range. Communications systems work at much higher frequencies than that (3 MHz and up, usually, and a park ranger is not likely to carry a radio with a 30 foot antenna, so it's most likely 300 MHz and up in this case), so unless the interference is over a very broad band, it's not going to have any effect on either radio or GPS signals.
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Post by wvengineer on Jan 1, 2015 4:45:20 GMT
Op states that birds and GPS are both affected, so that means a VERY broadband interference. Just going off of what the OP describes. Blame the writers.
Sorry, I wasn't overly clear in my last post. I meant that the comm headset could work if it was close enough the the transmitter of the comm signal. If it is close enough, a reasonable powered signal would have enough strength to be received over the EMI in the background if the receiver was close enough. Something like say a Bluetooth headset talking to a cell phone on someone's hip. However, a headset communicating with a base station several miles away would get lost in the EMI.
Also, frequencies above 100 MHz don't carry well over the horizon. Frequencies in the upper VHF and UHF+ bands are used for high data bandwidth but relatively short range communication, basically line of sight comm. Higher frequencies are also used because they penetrate better things like buildings, forests, etc. A UHF transmitter is lucky to get 50 miles with a high, tower, clear line of sight and a strong amplifier. To get further ranges, you need to get into repeaters. If you want to go long distances, you want lower frequencies. Something in the, say, 30 MHz and down range where you can get some atmospheric bounce to give you range. IF you are out in the middle of nowhere, If you want to hit a satellite, you want UHF to penetrate the atmosphere. HF to bounce a signal off the atmosphere and hug the ground for a long distance.
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Post by silverdragon on Jan 1, 2015 10:05:49 GMT
And what use is all of that website?.... All of us in the project already own DSLR camera's that were the price of owning and running a decent car when new. Do we now wish to pay again for a completely new and different camera? One that may not be as good as what we already have, just works underwater..... No. But do we want to sacrifice our own DSLR?.... Again no. But do we have the technology to put our camera into a thick safe waterproof environment to be able to do some underwater photography?.... Yes, yes we do, and why not?. One thousand dollars just for your camera..... (on that web site...) we intend to spend half that on a rig that will support MULTIPLE camera's, and be fully remote control.... As in, we are cannibalising a R/C Submarine. It will send Video back over a Wi/Fi network, hence this Raspberry PI I am playing on, and with a bit of luck, also send instant copies of the photographs taken back as well, via most camera's ability to plug in to USB. Yeah, sure, I can pay thousands for a submersible. But what fun is that?.. Buying the thing ready built out of the box?... What final satisfaction, compared to something a team builds. hey, you do what you want to for a hobby. I mean, I go into burning buildings, who am I to judge. but don't expect me to not point out that if your hobby is reinventing the wheel, you might advertise it as such. I realise that my reply may have sounded a little snarky, if so, problems in translation.... I apologise.... I am not re-inventing the wheel, What we are looking for are real world solutions that we can afford. Not ones that require us to start again with the investment.... We have camera, we wish to take photograph, and the salespeople say "Ah, but you bought the wrong camera".....
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Post by wvengineer on Jan 1, 2015 13:59:17 GMT
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