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Eliminating radio interference from Apple charger

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Re: Eliminating radio interference from Apple charger

#51

Post by NovemberWhiskey »

Animats wrote: post #10

> This radio interference was also present on the aviation frequencies (around 124 MHz) How did this thing get FCC approval? What's it's FCC approval number? Who tested this thing? Want to look that up. If RF got outside the charger and into the USB cable, it's very badly designed. The power in the USB cable is DC. There shouldn't be any significant RF component. There should be ferrite beads and capacitors in the po…

>How did this thing get FCC approval?

Looking at the radio display, it seems like the peak power is about 7-8 S-units. At VHF, that would be about -100dBm; or about 100 femto-watts. I presume that the charger is pretty near the radio. With free-space path loss being inverse square law, it's essentially going to be completely negligible within a very short distance.

Oh, and if the antenna is indeed near the charger (say within one wavelength, 2 meters in this case) it might be inside the near-field - which means that you're getting additional power transferred that wouldn't be reaching the far-field, and you might even be affecting the behavior of the device due to coupling.

Looking at the FCC report, the radiated emissions are totally in-line with FCC Class B requirements.

Modern ham radio equipment has exquisitely sensitive receivers and you easily hear all kinds of interference from digital devices that are completely Part 15 compliant. The prevalence of switched mode power supplies literally everywhere has made HF radio completely unusable for many people outside rural areas.

Re: Eliminating radio interference from Apple charger

#52

Post by stefan_ »

NegativeLatency wrote: post #2

I wonder if someone suggested this at apple and was overruled because a bulky ferrite would "look bad"

It passed EMC so the ferrite is not needed and omitting it is literally a million dollars decision. And no surprise, the spectrum images he posted look fine. It's not and never was about eliminating all emissions, and his problem is purely putting the thing right next to the receiver.

Re: Eliminating radio interference from Apple charger

#53

Post by crote »

NovemberWhiskey wrote: post #51
Animats wrote: post #10

> This radio interference was also present on the aviation frequencies (around 124 MHz) How did this thing get FCC approval? What's it's FCC approval number? Who tested this thing? Want to look that up. If RF got outside the charger and into the USB cable, it's very badly designed. The power in the USB cable is DC. There shouldn't be any significant RF component. There should be ferrite beads and capacitors in the po…

> How did this thing get FCC approval? Looking at the radio display, it seems like the peak power is about 7-8 S-units. At VHF, that would be about -100dBm; or about 100 femto-watts. I presume that the charger is pretty near the radio. With free-space path loss being inverse square law, it's essentially going to be completely negligible within a very short distance. Oh, and if the antenna is indeed near the charger (…

Do you have any idea how that power compares to regular FM radio broadcasts, which are somewhat close in frequency?

Is this something a regular radio would detect, or is OP just trying to listen to a handheld radio half a continent away using a really sensitive receiver with the volume knob turned all the way up?

Re: Eliminating radio interference from Apple charger

#54

Post by NovemberWhiskey »

crote wrote: post #53
NovemberWhiskey wrote: post #51

Earlier quoted context omitted.

> How did this thing get FCC approval? Looking at the radio display, it seems like the peak power is about 7-8 S-units. At VHF, that would be about -100dBm; or about 100 femto-watts. I presume that the charger is pretty near the radio. With free-space path loss being inverse square law, it's essentially going to be completely negligible within a very short distance. Oh, and if the antenna is indeed near the charger (…

Do you have any idea how that power compares to regular FM radio broadcasts, which are somewhat close in frequency? Is this something a regular radio would detect, or is OP just trying to listen to a handheld radio half a continent away using a really sensitive receiver with the volume knob turned all the way up?

To get a very broad idea: if you had perfectly efficient but isotropic antennas (you don't) this would be about the power level you'd get receiving a typical 3W hand-held radio signal at 140MHz from 1,000 kilometers away. This is why you can talk to the International Space Station easily enough with vanilla ham radio equipment.

Or, taking a notoriously powerful FM radio station like KRUZ 103.3, it would be like hearing that station from perhaps 300,000 kilometers away.

Most loss is not free-space loss though - it's due to reflections from man made objects and absorption into the earth that results in line-of-sight effects at these frequencies.

Re: Eliminating radio interference from Apple charger

#55

Post by colechristensen »

wkat4242 wrote: post #16
Animats wrote: post #10

> This radio interference was also present on the aviation frequencies (around 124 MHz) How did this thing get FCC approval? What's it's FCC approval number? Who tested this thing? Want to look that up. If RF got outside the charger and into the USB cable, it's very badly designed. The power in the USB cable is DC. There shouldn't be any significant RF component. There should be ferrite beads and capacitors in the po…

Yeah and the external wire will act like an antenna especially if it's got the right length. Very bad. Strange also because Apple usually gets their PSUs made by Delta afaik and they are as good as it gets.

It’s not very bad. Detectable signals is not at all equivalent to interference.

Folks need to relax. People actually experienced with RF wouldn’t worry about this at all, and the FCC is perfectly capable of doing its certification job.

Re: Eliminating radio interference from Apple charger

#56

Post by hellotheretoday »

wyager wrote: post #22
chankstein38 wrote: post #20

>But it really bothers me to buy 40€ product and I still need to fix it with component costing over 2€ Honestly doesn't surprise me. I hold the same kind of sentiment after spending $1200~ on a brand new iphone 14 pro max just to find that I had to buy the charger brick so I could plug it into a wall. Come on Apple. Eliminating QOL things doesn't just automatically equal improvement.

Probably like 98% of customers already have a USB power source of some kind, so that seems like a reasonable cut corner.

That doesn’t mean they have chargers that meet the wattage and port needs of newer phones. I still use an iPhone XS Max, which uses a 5 watt usb a charger. If I upgrade to an iPhone 15 I will need to get an usb a to c cable and the phone will take forever to charge. I don’t even know if that wattage is enough to charge the phone while it’s on, especially with the pro models.

Or they could just include a 20 watt usb c charger with my $800-1200+tax and activation fees phone and not force me to spend another $60 on their power adapter. though to be fair a third party option would certainly be less expensive.

Re: Eliminating radio interference from Apple charger

#57

Post by mschuster91 »

sdflhasjd wrote: post #28

This thread looks like a relevant one to mention an issue with the Mac Studio that causes large inrush currents when you plug it in. The power connector arcs badly enough to trip a domestic 30mA RCD, it's reproducable with several units and on different electrical circuits at both home and office.

The arcs have nothing to do with tripping the RCD part of your breaker. The RCD part only trips on a substantial current (>30 mA, or less for specialty devices, or more for upstream RCDs) between hot and ground, it doesn't care at all about the current flowing between hot and neutral.

That inrush current however, given sufficiently large buffer capacitors, can be enough to trip the overcurrent protection that most if not all RCDs also have - and that one tends to get more sensitive as they age, it's a common issue with old breakers.

(Another device that could trip is an arc-fault detection device, but AFDDs are fairly new and not required by many electrical codes. Nevertheless, it's a good idea to upgrade your distribution boxes with them, if you have the budget. These things save lives.)

Re: Eliminating radio interference from Apple charger

#58

Post by colechristensen »

chankstein38 wrote: post #20

>But it really bothers me to buy 40€ product and I still need to fix it with component costing over 2€ Honestly doesn't surprise me. I hold the same kind of sentiment after spending $1200~ on a brand new iphone 14 pro max just to find that I had to buy the charger brick so I could plug it into a wall. Come on Apple. Eliminating QOL things doesn't just automatically equal improvement.

I have a box full of various Apple chargers. Anybody who wants one can have one.

I’m pleased Apple stopped adding enormous amounts of ewaste by not producing tens or hundreds of millions of these things every year for the majority of people who do not need them.

Re: Eliminating radio interference from Apple charger

#59

Post by sdflhasjd »

mschuster91 wrote: post #57
sdflhasjd wrote: post #28

This thread looks like a relevant one to mention an issue with the Mac Studio that causes large inrush currents when you plug it in. The power connector arcs badly enough to trip a domestic 30mA RCD, it's reproducable with several units and on different electrical circuits at both home and office.

The arcs have nothing to do with tripping the RCD part of your breaker. The RCD part only trips on a substantial current (>30 mA, or less for specialty devices, or more for upstream RCDs) between hot and ground, it doesn't care at all about the current flowing between hot and neutral. That inrush current however, given sufficiently large buffer capacitors, can be enough to trip the overcurrent protection that most if…

The Mac Studio has a 3-pin earthed C5 connector. I presumed it's not overcurrent as it trips a 32A type C RCBO in an instant.

Either way, it's certainly a problem with the computer - I've far more demanding equipment that has never done this, and have yet to find a circuit it won't *pop*.

Re: Eliminating radio interference from Apple charger

#60

Post by Clamchop »

pnpnp wrote: post #43
stetrain wrote: post #15

Earlier quoted context omitted.

There's a big difference between causing interference in a receiver a few inches away versus an airplane 1000ft above you. It may be that this charger passes the legal requirements while still causing small amounts of interference when placed near a receiver.

There’s also a big difference between one charger emitting some noise, and a couple million in a big city raising the noise floor for the frequency.

It's not Apple's job to determine if there's a problem with that and regulations on this issue are, so far as I'm aware, treated very seriously.
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