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Re: [TowerTalk] Halogen Bulbs - 1.8 Mhz RFI

To: "K2DBK" <>
Subject: Re: [TowerTalk] Halogen Bulbs - 1.8 Mhz RFI
From: "Jim Lux" <>
Date: Fri, 26 Nov 2004 13:35:53 -0800
List-post: <>
I'd have to check Part 15 to be sure, but something at >9kHz probably fits
in the category of things that need to be tested/certified/what-have-you for
radiated and conducted emissions.  Except that there might be an exception
for "lighting equipment".
And, as has been discussed, even if they're supposed to design and check,
there's no guarantee that they do.

If it really puts out 20kHz AC (almost certainly a square wave, or close to
it), that's going to be a mighty fine RFI generator.  Can you crystal lock
it and use it as a marker generator? <grin>  Maybe a suitable rectifier
bridge and filter could make it 12VDC.

it probably falls under Part 15.3 as an "incidental radiator"
n) Incidental radiator. A device that generates radio frequency
energy during the course of its operation although the device is not
intentionally designed to generate or emit radio frequency energy.
Examples of incidental radiators are dc motors, mechanical light
switches, etc.
    z) Unintentional radiator. A device that intentionally generates
radio frequency energy for use within the device, or that sends radio
frequency signals by conduction to associated equipment via connecting
wiring, but which is not intended to emit RF energy by radiation or

If it is an Incidental radiator, the only requirement is:
Sec. 15.13  Incidental radiators. -    Manufacturers of these devices shall
employ good engineering
practices to minimize the risk of harmful interference.

If it's an unintentional radiator, it might fall into:

Part 15.103 Exempted Devices
(d) A digital device utilized exclusively in an appliance, e.g.,
microwave oven, dishwasher, clothes dryer, air conditioner (central or
window), etc.
    Maybe they're claiming it's an appliance?
----- Original Message -----
From: "K2DBK" <>
To: "Jim Lux" <>
Cc: <>
Sent: Friday, November 26, 2004 12:19 PM
Subject: Re: [TowerTalk] Halogen Bulbs - 1.8 Mhz RFI

> Jim (and all),
>     It's a "WAC Lighting Company" model EN-12PX-AR. Specs on the case
> say input is 120v 50/60Hz, output is AC 12V at 20kHz, 150W load max.
>    I did a quick Google check and it seems to be a pretty common PS.
> No FCC tag (unless it was on the side mounted to the wall, which I'd
> rather not remove unless/until I'm going to replace it.
> --
> 73,
>     David, K2DBK


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