Re: Automobile Cell Phone Charger RFI (followup)

Joe Puma

I haven’t seen a usb charger that didn’t take out my radio in my BMW X5. Great idea to use a SDR and console in the car. I may take a look at my situation but does anyone recommend a usb charger that is clean. I found some nice flush one that don’t pop out of the cigg lighter power, too bad the buggers are noisy. 


On Aug 31, 2018, at 1:32 PM, doug <dmcgarrett@...> wrote:

On 08/31/2018 12:27 PM, doug wrote:

> I have a 4 port charger that makes listening to FM barely hearable and totally wipes out AM. I had never thought of using SDRC to track it down.

> 73 Rick N2AMG
I am sort of surprised that your device contains a switcher when all you need is 5 Volts DC from a 12 to 15 volt cigarette lighter socket. I would put a 5V series regulator in the charging device and it
would make no RFI at all. Perhaps there is one made like that. I have a two-port lighter plug with USB jacks on it. I will take a look and see if it generates RFI. And my phone came with a separate
charging cord compatible with a USB jack, which the AC charger has on it. (And IT is a switcher of course, sind it plugs into
In the meantime, Does the device you have have a built-in charging cord that goes to the phone, or do you use a separate USB to phone cable? If it's a separate cable, then disconnect it and see
if the RFI goes away sufficiently to listen to the radio. If it does, then get some ferrite snap-on RF chokes and run the charging cord thru about three of them right next to the lighter socket.
If that doesn't work, you will have to find a charger made with that series regulator.

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