#RFShields #HomeElectronics #EMRadiation
Have you ever wondered why RF shields are used in home electronics? 🤔 What exactly do they do, and are they really necessary in today’s technology? Let’s dive into the world of RF shields and uncover their importance in protecting our devices from electromagnetic radiation.
## What are RF Shields?
RF shields, also known as radio frequency shields, are protective barriers used in electronic devices to prevent interference from electromagnetic radiation. They are typically made of materials that are good conductors of electricity, such as aluminum or copper, and are designed to block or absorb radio frequency signals.
## Importance of RF Shields in Home Electronics
### Protection from Electromagnetic Interference
1. **Prevents Signal Disturbance**: RF shields help to prevent external electromagnetic interference from disrupting the signals within electronic devices.
2. **Ensures Proper Functionality**: By blocking unwanted radio frequency signals, RF shields help ensure that electronic devices function properly without any interference or glitches.
### Safety of Electronic Components
1. **Prevents Overheating**: RF shields can also help prevent electronic components from overheating by blocking excess electromagnetic radiation.
2. **Improves Longevity**: By protecting electronic components from electromagnetic radiation, RF shields can help extend the lifespan of devices.
## Common Examples of RF Shields in Home Electronics
1. **Smartphones**: Many smartphones have RF shields to protect the internal components from external electromagnetic interference.
2. **Laptops**: Laptops often have RF shields around the processor to prevent overheating and ensure optimal performance.
3. **WiFi Routers**: WiFi routers use RF shields to prevent interference from other electronic devices and ensure a stable connection.
## Are RF Shields Still Necessary in Modern Electronics?
Despite advancements in technology, RF shields are still a crucial component in many electronic devices. Here’s why:
1. **Increased Electromagnetic Pollution**: With the growing number of electronic devices in our homes, the risk of electromagnetic interference has also increased. RF shields help mitigate this interference.
2. **Regulatory Compliance**: Many industries have regulations in place that require the use of RF shields to protect electronic devices from external interference.
3. **Protection from Hacking**: RF shields can also help prevent electronic devices from being hacked or intercepted through electromagnetic signals.
## Debunking Myths about RF Shields
### Myth 1: RF Shields Are a Relic from the Past
While RF shields have been around for a long time, they are still relevant in today’s technology-driven world. As electronic devices become more advanced and interconnected, the need for RF shields continues to grow.
### Myth 2: RF Shields Harm Electronics
There is no evidence to suggest that RF shields harm electronic devices. In fact, they are designed to protect devices from harm caused by external electromagnetic interference, making them essential for the proper functioning of electronic devices.
In conclusion, RF shields play a vital role in protecting our home electronics from electromagnetic interference and ensuring their proper functionality. While they may seem like a small component, their impact on the performance and longevity of electronic devices cannot be understated. So next time you see an RF shield in your smartphone or WiFi router, remember that it’s there for a reason – to keep your devices running smoothly and efficiently.
Back in 90s early 2000s I knew my cellphone was going to ring because my speakers would make noise. The vacuum would mess up the TV picture. I remember we had something to close to a old plasma TV and turned the corner purple. So some reasons.
The shielding is to prevent unwanted emissions of RF. Devices need to be tested and certified by the FCC.
If they could get away without the RF shields they would have. A lot of things in electronics involve switching power on and off very quickly. For example the processor and graphics chip is constantly switching at its clock frequency in order to do calculations. So for every clock tick there is a huge power draw. Modern more powerful processors have even bigger power spikes. The current going through the wires like this makes the wires act like antennas.
And if you think about processor clock speeds they might often end up in the 2.4GHz range which is used for WiFi and Bluetooth. I have seen laptops with inadequate RF shielding lose WiFi signal at specific processor loads. And while most processors can not get up to the 5GHz band there are harmonics which can disrupt even this band. And then you have the new 6GHz band used by WiFi6 where other harmonics can reach. And then you have cell phones which use a number of frequency bands like 600MHz, 900MHz, 1.7GHz, 4.7GHz, and up. If your electronics is not shielded it will disrupt traffic on these bands.
It also goes the other way around. If your cell phone receives a call and therefore outputs a lot of radiation, something you might have heard through poorly shielded speaker cables. Then this signal will get picked up by the wires to the processor and if there is some harmony with the clock frequency it may disrupt the processor, most likely causing it to crash.
Every home electronics device is tested. They put it inside a chamber that blocks any RF interference from the outside. And then they test how much radiation it puts out on all frequencies. If it is lower then the legal requirements it passes. And then they test it while bombarding it with radiation at various frequencies and check if the device fails in any way. If the device is passes this test the engineers go inn and remove some of the shielding trying to make it cheaper to manufacture, and then they redo the test. They want to get away with as little shielding as possible. But usually they need extra radiation shielding between the processor, graphics card, WiFi module and power supply as these can interfere with each other due to their close proximity. But the engineers also have to take into account that people may leave their phone on the device or even connected to the USB port to change. So they need proper RF shields to the environment.
The government has very strict regulations on the amount of electromagnetic noise that a device can emit. This is to ensure that your electronics don’t disrupt the function of other devices.
The metal shields help to reduce emissions from noisy subassemblies in the unit – usually a switching power supply or processor. [source: part of my job is to take consumer electronics products to FCC/CE testing labs]
The shields are not there to ‘protect’ the electronics from radio frequencies. They are there to prevent interference. Things like video and audio outputs are very susceptible to radio frequency interference and would produce things like static/pops in audio and visual imperfections in video. The shields reduce these impacts.
they do the same thing as a “tin foil room” also known as a miniature faraday cage.
they keep the electrical noise inside the cage.
or they keep noise out of a sensitive circuit.
the fcc rules have two classes of things: an intentional radiator, and an unintentional radiator
an intentional radiator is like a wakie-talkie or cellphone or wifi device it is suppose to transmit intentionally.
a radio, like the one in a car to play music or to listen to the news or your television is not purposely transmitting (radiating rf signals) but it does any way.
some times to stop or shield this you put it inside a metal box
when i was a kid i had a trs80 model 1 it ran at about 4mhz, my room was next to the living room. when i turned on the computer the damn color on the tv went bonkers.
this was a problem because on sunday my dad wanted to watch football, and i would goto my room to play on my computer.. and the tv went crazy so bad that my dad forbid me to use my computer when the football game was on.
later versions used a copper based paint on the inside of the computer case, but i had an early one that did not have this special paint.
You remember old TV-s and radios making weird noises when a cellphone next to them got a call? Yeah, radio frequency interference is a thing. But if a piece of analog electronics just makes a funny noise, then the same funny noise in digital electronics is complete nonsense data that does not compute. That can in some extreme cases just brick devices if it gets saved instead of data that was supposed to mean something.
I make electronics and our org tests everything for em interference. When they fail, it is sometimes really obvious. Have a thing with cap touch buttons? Noise makes phantom button presses and turns your shit on and off at random. Com protocols? Half your messages just drop and you have to slow communications or just never get messages.
So we upgrade the hardware and firmware to handle the em so our gear doesn’t suck ass.
In most cases the RF shielding is actually not to protect that device but to keep that device from interfering with other devices. It is required to be limited so that it doesn’t interfere with other devices under federal law.
Pretty much any modern electronic device transmits information over wires internally at one frequency or another.
How do you create a radio transmit a signal over a wire. So basically all of these devices give off some EM/RF.
[https://transition.fcc.gov/oet/info/documents/bulletins/oet62/oet62rev.pdf](https://transition.fcc.gov/oet/info/documents/bulletins/oet62/oet62rev.pdf)
[https://www.fcc.gov/oet/ea/rfdevice](https://www.fcc.gov/oet/ea/rfdevice)
“This device complies with part 15 of the FCC rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.”
That is probably one of the worst worded statements. By accepting interference all it means is it won’t try to interfere with the outside transmission. You could operate your device in a Faraday cage and ground it. The chassis could do that. That would be legal. It would accept outside interference that way without interfering back. It is just grounding that interference.
I am the farthest thing from an electrical or RF engineer, but I have been wondering about 80’s era computers in particular. I mean, things like Commodore 64s and Ataris and stuff would have relatively thick shielding “cages,” but this seems to not be the case with consoles and things any more.
Is it because these sort of devices had RF modulators that output TV signals? I know that most PCs and entertainment devices like surround amps, etc. have metal cases, but I see lots and lots of high-end PC builds that are “open frame” or have huge plexiglass openings, etc. These seem to not have much adverse effect to other things of be adversely affected.
Most shielding is to keep interfering signals in. You may have heard buzzing or other sounds if you’ve put a radio put near electronic devices. WiFi and phone signals can also be obscured by improperly shielded devices. Shielding stops these problems. The FCC requires shielding to prevent radio signal interference in some cases.
Another purpose is to keep sensitive electronics in the device from being influenced from external signals, or from signals created in one part of the device from causing noise in another part of the device. You’ve probably heard power line hum in audio equipment. Powerlines and other sources radiate signals that can couple into the electronics of a device. These cause problems such as noise in audio signals, image artifacts in video signals, poor performance in radio electronics, poor reception of radio signals, and others. Shielding helps keep these noise sources away from where it would cause a problem.
My laptop drops wifi frequently, and this seems like the exact reason why. It’s definitely not abandwidth issue. What do I need to shield to prevent this? Or can I prevent it at all?
You’re swimming in a thick ocean of radio waves. Most things like light bulbs don’t care. Sensitive stuff can be interfered with by back ground noise, radio from space, cell phones. So yes, its really needed and not just an old timey thing
It’s worth understanding that our electronics create EM radiation whether they intend to or not, and all can be disrupted by the right power and frequency of EM radiation from other electronics. Given how many things are creating and depending on EM radiation these days, the shielding is probably more important than ever.
I’m using cheap LED shop lights as grow lights in my dining room. Due to RF interference, I can’t turn on/off my wirelessly-operated kitchen ceiling fan when they’re on. Or open or close my garage door when they’re on in the garage.
RF shields serve 2 purposes. It protects what’s inside from external radiation and it protects what’s outside from emissions from the inside. A given device could need a shield for either reason. A device would be tested in a special facility for both emissions and immunity. It needs to function properly in the presence of radiation and needs to generate less than a certain level so it doesn’t interfere with other stuff. A given device might need shielding for either reason and there is a cost involved so if it can do without it certainly would.
There are three different kinds of EM shielding – The first is the kind that’s built into every electronic device which reduces harmful or undesirable interference to or from other electronic devices. The second is the EM shielding that they market to gullable Aunt Karen because EM waves are “harmful radiation” (they aren’t*) and they’ll “give you cancer” (they won’t*) and by blocking these waves, you’ll live a long healthy All Natural life. The third kind is the kind that they market to crazy Uncle Jeff that will protect his electronic devices frem the EMP when The Chinese/The Russians/The Koreans/The Liberals launch their attack and nuke the United States.
Only one of these kinds of shielding is worth a damn and actually does what it’s supposed to. I’ll leave it up to the reader to noodle that one out.
A colleague of mine had his laptop connected to a machine he was programming. Turns out, a machine nearby was impropriety shielded, which fried his laptop. Good times.
>Why have RF shields in home electronics? What do they actually do??
>
>Protects your stuff from EM radiation and stuff, but is this really a concern
You seem to have this backwards. RF shields are not to protect your devices from interference but rather to limit the RF interference that your devices emit. By making it a legal requirement for devices to limit their EM emissions we can create an environment where devices do not need to be heavily shielded from outside EM interference which reduces overall costs and complexity.
Now a example of what life would be like if limiting EM emissions was not a requirement. I had a neighbour way back in the day who had a lawn mower that would generate a ton of EM emissions due to a improperly shielded spark system and when they were mowing their lawn it would be impossible for us to watch TV or use computers because the lawnmower was creating enough EM interference in the right frequency bands that the TV and monitor would display a wall of fuzz instead of the proper picture. Another neighbour was a shortwave radio enthusiast who had a improperly grounded transceiver which meant that when he was talking to people on his radio I could hear it over my computer speakers – I ended up having to make a complaint to the ACMA (Australian equivalent of the FCC) to get him to fix his setup (they would have threatened him with massive fines if he didn’t fix it by properly grounding his setup).
All these things are buzzy. They might not seem very buzzy, but the people who make them are really really good. If you have these buzzy things by other buzzy things, their buzzy-ness gets all wonky, and they don’t work right. The RF shields make sure this doesn’t happen.
Radio nerd here.
You’d be surprised how much RF household devices put out. With the right equipment I can tell you a Lot about what kind of electronics are being used within a block of me.
The other thing to consider is that there is a LOT of high energy RF out there that you likely have no idea exists because all your stuff is shielded. Not just from local stuff either, sensitive consumer electronics would suffer from the EM put out by the sun if they weren’t shielded.
Yes, it’s 100% a problem!
For example, Bluetooth mice operate at 2.4Ghz. By coincidence, the speed of a USB 3.0 signal is also *roughly* in that frequency range. This means that if you don’t have proper shielding for your USB devices they can interfere with your Bluetooth connection. Bit of a problem, especially considering Bluetooth dongles are usually plugged into a USB port, *right next to potential interference*. Intel wrote an [entire whitepaper](https://www.usb.org/sites/default/files/327216.pdf) about it.
Most non-wireless devices don’t really care all that much about incoming signals, so the shielding isn’t needed to protect it or something. However it’s **very** easy for electronics to accidentally *emit* signals, often at unpredictable frequencies. The shielding is needed to keep all the bad stuff in and stopping it from potentially interfering from all kinds of wireless devices anywhere even remotely close to it.
power wires aren’t shielded. only signal wires (and some sensitive components.)
the shielding prevents stray electromagnetic interference from corrupting the signal by draining away the excess current.
all environments experience stray EM waves but especially the 6 inch +\- cooridor surrounding power cables, 60hz (or 50hz in Europe)
signal wires within this “corridor” space would be engulfed in and completely obscured by the induced current without shields
power wires are high voltage. 120volts (240v in Europe) alternating current. this creates a corresponding electromagnetic magnetic field around the wire.
signal wires are low voltage. 5v, 3v, 1.5volts etc. DC “direct current”. (one way, not alternating) easily over powered by adjacent power wires EMF.
so in home appliances, you typically see the entire power supply surrounded by a shielded box to help contain the EMF. and sensitive signal wiring and components shielded to further protect from from EMF.
some times a simple circuit can operate in a “dirty” environment because it’s not critical to operation. an LED light for example is only switching power to run a lamp. you wouldn’t notice if the circuits were “dirty” because it would only very slightly change the light intensity. sound equipment, tvs, and computers however couldn’t operate “dirty” because the signal’s integrity is crucial.
it’s amazing how difficult it is to describe this in a concise way because there are so many assumptions about current and magnetic fields that must be understood first.
Radio absolutely effects electronics and anyone that got a text in 2005 near a computer speaker knows that as a definitive fact