[RFI] RFI-free Vehicle 5v USB Adapter?

[Greg Troxel]

"qrv at kd4e.com" <qrv at kd4e.com> writes:

> I just discovered that the 5v USB adapter I installed in my
> '86 Suburban is a RFI-monster.
>
> If the USB cable is anywhere near a radio it wipes-out SW.

A few datapoints:

  I have a few Anker dual-port lighter/USB devices.  WIth them in the
  shack, charging phones, and running an esp8266, I don't hear them.
  That of course doesn't prove totally quiet; it means less than my
  other noise.

  I tried a DROK buck converter board, to make 5V from 12-15V for an
  ESP8266, and it was dreadful in terms of noise on the voltage rails
  for supporting an ADC to measure the batteries.  Have not observed RFI
  because it didn't work well enough for purpose, and needs
  bypassing/filtering obviously.

  I have a few other lighter/USB things, and none of them have seemed to
  be egrerious.

other:

  Avoid really cheap stuff.  There's a reason it is cheap.

  I wonder who much of the trouble is from the converter, and how much
  of it is putting an antenna on your car 12V system.   My converts are
  on batteries (200Ah lead acid, solar float with genasun).


73 de n1dam