171–179 of 179 posts
> The final product showing the ferrite bead with three wraps of the interference causing USB cable around it. Isn’t that just two wraps? Or two and a half at best?
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The "bulky ferrite" he used is an easy 'hack.' the correct way to fix this wouldn't be as expensive or as bulky, as noted in the article: "I expect Apple could solve this problem with much cheaper and hidden it somewhere cleverly."
I'm not so sure. I can't think os a solution other than a choke off the top of my head.
Smaller, cheaper, lighter, better. Just hard to retrofit if they weren’t designed as part of the board to begin with.
so does this make charging more efficient? does it help preserve hardware in the long-run? is there a guarantee that these frequencies weren't added in for some engineered purpose?
I have a feeling this makes charging less... not efficient, but slower charging. The end of this thing is a bunch of wire in a loop, the inductor that transfers the energy to the phone. So it was odd to me that he chose the cord as the antenna that was broadcasting the noise, when I'd think it would be the business end. These frequencies being broadcast might be overlooked harmonics, ok to filter out, but they might…
So, no, this doesn’t slow down charging.
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> nothing faster than 300k That is exactly one of the misunderstandings I’m trying to warn that you are missing. I’m certain that your switching transition times are massively faster than the 300k period (each rise and fall time). You can have split grounds, but you don’t have traces under your grounds so in many cases you aren’t even effectively using them. You are grounding a portion of every signal inside every ot…
off topic, but what do you think of this video by Asianometry talking about the intricacies of analog design for a laymen audience? https://www.youtube.com/watch?v=lNypq1XuZRo
Then out of no where it's talking about tantalum nitride...
No, I'm pretty sure that video was made by an AI.
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> Broadcast stations are some of the highest-power radio transmissions around us, typically thousands of kilowatts (for example the rock station near me transmits at an ERP of 51,000 watts[0]). I don't think so. Not "thousands of killowatts" transmitted. Your example is as you say, an ERP of 51kW. But even ERP doesn't refer to the transmitter. An ERP of 51,000W is most likely a 5-10kW transmitter, with a gain factor…
Back in the pirate radio days 100 and 250kw transmitters were common. Back in the '30s a few AM stations ran at 500kw, and could be picked up on other continents.
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Due to proximity, the interference from the charger is comparable to what the receiver was expecting from a normal signal (like an amateur radio repeater or fellow operator's station), which is why his radio broke squelch while scanning. Because the radio is relatively close to the charger, the RFI is picked up quite well. Comparing to a broadcast FM station, the strength of the RFI as observed by any nearby radio wi…
> Broadcast stations are some of the highest-power radio transmissions around us, typically thousands of kilowatts (for example the rock station near me transmits at an ERP of 51,000 watts[0]). I don't think so. Not "thousands of killowatts" transmitted. Your example is as you say, an ERP of 51kW. But even ERP doesn't refer to the transmitter. An ERP of 51,000W is most likely a 5-10kW transmitter, with a gain factor…
I'm quite frankly amazed that this is the first time this guy has had to put a choke on something as a radio amateur. I guess he doesn't use HF that much otherwise he'd probably have opted to buy an entire bag of ferrites. Maybe his magsafe charger really is bad, but if it's plugged into a computer or a crap charger it's also likely that it's just RFI riding the cable straight out of the computer. USB stuff is the wo…
where can one buy a bag of ferrites?