[RFI] Raspberry PI / Wall wart RFI

[N4ZR]

Jameco has a bunch of 5 and 12-volt linear wall warts for quite 
reasonable prices.  For example, their 5V unregulated 800 ma wall wart 
is $3.90, and a 12V 2 amp unit is $13.95.  There are a lot in between.

73, Pete N4ZR
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On 4/2/2021 8:49 PM, Jim Brown wrote:
> That's because it's a switch-mode power supply. What voltage and 
> current?  Depending on that, it may be possible to re-purpose an old 
> linear wall wart. Also, study my tutorials on chasing and killing RFI. 
> They include specific advice on subbing the linear supply.
>
> Text:  http://k9yc.com/KillingReceiveNoise.pdf
> Slides: http://k9yc.com/KillingRXNoiseVisalia.pdf
>
> 73, Jim K9YC
>
> On 4/2/2021 5:15 PM, David Gottschalk wrote:
>> I'm wondering if anyone has had success finding a wall wart for a 
>> Raspberry
>> Pi that doesn't make horrific RFI on HF (or really any switch mode power
>> supply that isn't noisy!)
>>
>> I recently discovered the wall wart for my Raspberry PI (that is mounted
>> outside in a water proof enclosure for my 4G internet) is making S7 
>> level
>> noise on 80m. Unfortunately, my 80m loop is currently pretty close to 
>> it.
>> When the PI is battery powered, or off, it's S4 noise level here 
>> (This is
>> in the middle of the day). 60m also seems to be severely affected as 
>> well.
>>
>> I found this on Amazon, but it seems like it's more of a AC line
>> conditioner, but might be worth a shot. Any feedback would be greatly
>> appreciated.
>>
>> https://www.amazon.com/iPower-Supply-International-Travel-Adapters/dp/B01GNNXP0Y?ref_=ast_sto_dp&th=1 
>>
>>
>> 73,
>> David
>> KN4ZKT
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>
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