Dave Hachadorian K6LL at ARRL.net
Fri Nov 21 07:25:13 EST 2008

My neighbor's kid had one of those scooters. I bought them a 
cheap outdoor timer so they could charge it up in the middle 
of the night. After a few weeks, the scooter broke down, and 
there was no local repair support, so the problem went away. 
I also purchased one of the chargers on EBay, put it in a 
metal box with filters on the input and output, and it still 
made too much noise. Those chargers are definitely bad news.

Dave Hachadorian, K6LL
Yuma, AZ

----- Original Message ----- 
From: "Jim, W4ATK" <w4atk at bellsouth.net>
To: <w9ac at arrl.net>; <rfi at contesting.com>
Sent: Friday, November 21, 2008 11:57 AM
Subject: [RFI] RFI

> Paul,
>    This type of noise is characteristic of a Chinese made 
> switching
> battery charger. I will just bet one of the neighborhood 
> kids has a
> Chinese made electric scooter.  The charger is 36V and 
> very bad news.
> The frequency will change as the battery charges, but will 
> always be a
> consistent 56KHz. A lot of people will confuse this with 
> the refresh
> rate on some monitors. I can supply photos of the 
> offending charger and
> scooter if you would like. I have one two doors up the 
> street from me.
>    ICE makes a filter than will go a long way toward 
> clearing it up,
> but it is expensive. I have worked out an arrangement with 
> the owners
> that stipulates that the charger will only be used when 
> there is
> expected use of the scooter. Alas, they forget and leave 
> it plugged up
> and eventually I will have to call.
>    If I can be of further assistance, drop me an email.
> 73s Jim, W4ATK
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