[SCCC] OT: low RFI USB-C power supply?

[Steve Harrison]

I gave up on switching wallwarts years ago and now just replace them 
with regulated homebrew linear (transformer-powered) power supplies. You 
can never get them quiet-enough. Even the Hewlett Packard one for my 
laptop creates some noise that I wasn't able to completely eliminate so 
I had to not only make a linear supply, but also determine how to drive 
that third wire that HP uses to try to circumvent my using an external 
supply. What a PITA. Now my small AC-powered "ceramic" heater is 
producing noise on 80, I discovered last night. At least, I don't use 
that one much, and I have a real-old-fashioned type with resistance wire 
I'll drag out onna these days.

Steve, K0XP


On 11/3/2023 8:38 AM, Ryan Huggins via SCCC wrote:
> I have not done any evaluations myself, but I did a quick search and saw a similar discussion on a Flex Radio forum.  Someone there recommended "Jameco" as a source to buy good ones.  I took a quick look at their site and found this one:
> https://www.jameco.com/z/DCT18W050300US-A0-Jameco-ReliaPro-5-Volt-3-Amp-15-Watt-Regulated-Switching-Wall-Adapter-USB-Type-C_2318927.html
>
> It does not specifically mention RFI, and I assume you can contact them with the question, but it is UL and FCC stamped which gives me hope.  It's only $8 too.  Would be worth checking into their return policy.
>
> I've been hunting down RFI in my house as well.  Lots of type 43 ferrites and kits from Palomar-Engineers.  I had a wall wart for my Roku that was putting off 2-3 bars worth of noise (granted on the other end of the house).  A couple wraps through a clip-on ferrite helped reduce that greatly, so that may be an option too.  I put one at the Roku end as well.
>
>
>
> -73
> Ryan, KI6BTY
>
>
> On Friday, November 3rd, 2023 at 8:00 AM, Drew Arnett<arnett.drew at gmail.com>  wrote:
>
>
>> I've started chasing down a new noise source at home. (Early
>> assessment shows it's getting on the AC wiring and conducting all over
>> the house.) Probing around, looks like a new piece of gear that is
>> powered by USB-C and has a USB-C wall wart that was included is quite
>> RFI hot. I'm hoping it's the supply and not the load, so swapping
>> supply might cure it.
>>
>> USB-C power supplies are somewhat new. None are going to be specified
>> for conducted or radiated RFI. Has anyone done any evaluations, so I
>> can simply purchase once? Or do I have to do the equipment
>> evaluations?
>>
>> Thanks and best regards,
>>
>> Drew
>> n7da
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