The issue isn't that the components in these supplies are cheap, it's that necessary filtering components are not in there at all.
https://en.wikipedia.org/wiki/Power_factor#Switched-mode_pow...
Do you mean devices with RFI-suppression components omitted to save cost? Those devices are subject to FCC part 15 rules just like devices manufactured domestically.
> from off-brand vendors
Again, who is supposed to enforce that these vendors comply with US laws? My point is that those laws are not enforced. The reason that look-alike Apple USB charger costs $3.99 is because it contains no RFI suppression parts and is probably made with toxic plastic.
It is the job of regulators to shut down firms importing this garbage. By failing to do so the regulators harm the people their regulations are supposed to protect. Meanwhile, US firms who comply with the rules can't sell their USB chargers for a competitive price so they go out of business.
Thankfully Kodi streams from SMB shares extremely well.
But just as firms want to be able to import steaks that have been made from cattle raised near polluted foreign rivers, firms import power supplies made with RFI-suppression parts omitted because someone along the way wants that $0.15 as profit and US regulators don't care.
Incidentally, a law was passed fairly recently that allows agricultural firms to remove information about where food items were produced, so quite possibly the steaks we eat will soon be made from cows who drink the water runoff from the polluting factories that make the low quality switching supplies.
Our "first world" environmental regulations (food quality, air and water quality, RF noise floor) are only as good as our regulation of imported products that commit fraud by selling products that do not comply. By failing to enforce these laws, US regulators have helped foreign firms cheat their way into the US market, putting US firms out of business and harming consumers indirectly by polluting their environment.
I'm not arguing that all of those regulations make sense, just that it is silly to have laws that we don't enforce when the health consequences and RFI consequences harm everyone.
Most consumers won't realize that the USB charger they purchased for a fraction of the cost of a name brand product is why their phone's battery capacity declined so quickly.
With so many sellers on Amazon doing bait-and-switch, solving the problem is going to be very difficult for Amazon to solve without causing a disruption in the flow of low-cost electronics.
I fixed this by putting the USB 3.0 thumb drive through the washing machine in my pants pocket. After being washed, the thumb drive no longer works, but my wi-fi is working great now, thanks to the washing machine. Problem gone.
Given current data in the area of climate change (I say this as a California resident who has seen firsthand the effects of long term drought in the area), we need to consciously conserve water. Reservoirs are drying up, fires are out of control, etc. Please don’t contribute to the problem. Use a hammer.
USB now works great!
https://forums.macrumors.com/threads/usb-3-causing-interfere...
Apple's article mentions USB 3 devices, but the issue is very much with Mac Mini's ports. Moving the devices further away doesn't help much.
I have a pair of cheap Bluetooth earbuds. They have a range of about 30 feet with when paired with an iPhone and about 4 feet when paired with the Mini. Apple's Magic Mouse needs to be within about 4 feet to work as well.
I'm glad I can finally have some closure :P
This explains so much. FFS.
The first is the C plug spec.
The second is the USB 3.1 protocol and cable spec.
The third is the USB power delivery spec.
All of these can be mixed and matched as the OEM sees fit.
I realize TPMS is not 2.4gz but thought that was relevant to interference concerns
http://support.logitech.com/en_my/article/38032?product=a0qi...
Took me a week before I learned that I need to plug in the Logitech wireless USB thinger directly in to my laptop. Plugging it into the hub made the mouse partially unresponsive.
1. Do not place USB ports near antennas, or RF parts 2. USB allows for rather large deviation from base frequency, use a drifting frequency source to spread the emission spectrum 3. Use shielding where possible
[1] One I can sometimes trick with a "headless" DP cable, but even that isn't reliable enough to stick in a closet and forget about.
[Edit: plenty of other comments about Logitech issues too]
EDIT: I came across this whitepaper when looking into the problem a few years ago and just accepted that performance of wireless mice and keyboards is going to be bad. I haven't yet seen any good bluetooth replacements. Most of the bluetooth keyboards I see are smaller without 10-key. I think I had a bluetooth mouse at one point and the lag was unbearable (given, this was years ago, so maybe they're better now).
Only usb-to-bluetooth dongles are likely to have the signal strength to penetrate walls. Mobile devices, and in particular earpieces and similar small devices, are likely to use weaker signals that rely heavily on being reflected off surfaces to get around obstacles.
And one such obstacle is the human body. Thus putting you phone on one side, and the ear piece on the other side may results in poor reception. But standing near a surface, be it a wall, a car, or something else, in front or behind may allow better reception as the signal can bounce off said surface.
(also, when I first wrote this, I was half-kidding until I read https://en.wikipedia.org/wiki/Fly-by-wire#Fly-by-wireless)
RFI most frequently affects wired equipment. Radio-radio interference doesn't happen as much (due to SNR margins, protocol design etc.)
Advice: buy USB 3.0 accessories with good shielded cables.
...That would actually be rather fun to see, like http://www.erikyyy.de/tempest/
Of all the frequencies to interfere with...
I bought a cheap 3rd party one, when I used it I could not use WiFi. When I replaced the cheap one with an Apple one everything worked perfectly.
Also 802.11aX is out soon, it will use 2.4/5ghz just with a bit more bandwidth on both, so you may want to just wait for that instead. (edit: looks to be maybe +25% or so more)
The 2 meter radio I have in my car goes crazy with RF(up to S9) when I drive through the local Starbucks. That said bringing it up with anyone will probably get you a couple funny looks and not much else.
(things are even worse on HF and the like)
I integrated the total power with a spectrum analyzer... but any radio I tested (including GPS, FM, WiFi & GSM maybe due to IF or saturation?) would stop working within 10ft=3m of the lamp. Driving around I could tell if the lamp was on using my AM radio (set to any station) due to the 120Hz buzz from several blocks away.
As far as I could tell it had passed Korean FCC equivalent, several tens of thousands were imported, and sold (at Frys at one point) around the country.
I destroyed ours, but sometimes, just driving around, I think I can hear one when I switch to AM.
I really love the form factor - about four of these would replace close to a kW-worth of hardware I currently run, and could hide in a closet. Maybe I should try again with known-good versions.
Just bought a laptop, and now you need to start hacking it up and changing the wifi-card so it doesn't cause interference to itself? What next, break out the soldering iron and go over all the cold joints?
We can only keep the spectrum in good shape by, as a producer or designer, test and design to comply. As an importer, require and check certifications on what we import. As a consumer, report when we find something being funky. (again, not blaming you)
I don’t think there would have ever been any legitimate concern of low-power digital devices like mobile phones causing any problems like coupling into control systems or anything... Digital radios are typically much better filtered and far lower power than analogue radios.
The company I work for makes satellite antennas for ships and large road vehicles, and the only time we’ve had a problem like that was when somebody mounted a 20kW S-band weather radar three metres from our antenna. It just requires a little extra shielding in one module though.
That being said, unofficially I agree, given Wi-Fi is provided on flights now, I'm sure that means you're alright to leave your Wi-Fi radio on. The answer to why shut off all GSM/CDMA, Bluetooth, and GPS radios as well, however, probably predates the high prevalence of all these wireless technologies in a unified device.
In the latter case, they would (I'm assuming) be flown with proper high gain directional antennas instead of tiny antennas mostly hidden inside a metal tube that attenuates most of their signal
How did that ever make it past FCC certification? I understand unintentional QRM from cheap things but that is something that's spec'd out.
Unless I'm mistaken?
My guess is that the connection to your house to the service wires in incredibly low impedance, otherwise you'd see all sorts of voltage sags when you used a large appliance with an inductive load(or power tool). So any change large enough to affect the service line is going to go straight into your house. Circuits aren't directional(unless you have a diode or voltage/impedance follower) hence why it would impact the quality of power-line networking.
Additionally any sort of low pass filter(RC, LC or RLC) involves putting a inductor(P) or resistor(R) in series with the circuit(AKA your transmission wires) which isn't simple or cheap.
My understanding is that you mostly care about the minor reflections caused by wire junctions in a system like this, and that line headed outside is more or less a signal sink no matter what. It's possible a capacitor would need to be a bit further away than directly at the breaker box, but by the time you reach the pole I'm reasonably confident that absorbing the entire signal with $.50 of components and no inductor would be fine.
Is your house longer than 32ft/64ft? Those lengths are halfwave on 20m/40m and make a great radiator. For reference all I need is 5w to get out ~400mi so I'm sure these things are kicking off a ton of RF on those frequencies.
Fundamentally if you have an unshielded wire and you're driving these frequencies across it you're going to see RFI along those frequences(along with the harmonics).