I am interested in testing RFI originating from LED T8 replacement bulbs, which are seated in troffers. Original ballasts have been removed from the troopers. Is there a simple test that can be performed without special test equipment? The goal is not necessarily gain a quantitive measurement, but to understand if and what frequency bands are impacted.

The issue is not critical (yet), however, I would like to know if there are simple / inexpensive methods to test. I am seeking tests that can be performed with equipment under $100. I would think that the most important spectrum to guard are the cellular and wifi bands: a UBNT Nanostation might be repurposed.

  • I would contact the mfg, T8 retrofit usually use a mosfet driver as the heart of the power supply and the manufacturer already has this information, however the RFI will be much less if it is a ballast bypass, if it is a plug and play (keeping the ballast) the original RFI listing of the ballast + & - the driver RFI. Whithout a spectrum analyser it would be difficult to find the frequency. – Ed Beal Sep 22 '18 at 16:01
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    Are these going in troffers? How critical is the EMI issues? What's youur budget? – Harper - Reinstate Monica Sep 22 '18 at 17:02
  • @Harper Good question: OP updated to address the questions – gatorback Sep 23 '18 at 18:39

A FM radio tuned to a weak station may indicate if there is interference, and tuning it to a frequency with no station may also work as detector. Muting must be switched off. An AM radio can likewise detect interference in lower frequency ranges.

LED bulbs/lights often are a big source of problems concerning RFI. Due to the pulse width modulation in the LED power supply, a wide frequency range is emitted if no filters are used in the LED electronic. There are cheap LED bulbs with a simple RC- network as power supply resulting in less interference, but they flicker - visible by quickly moving a finger or pen up and down in front of them.

When shopping LED bulbs, a RFI test can be performed with the radio (and earphones as antenna) that comes with many smart phones, but a muting switch is often missing. When purchased via Internet, LED bulbs can be tested at home and sent back if they fail.

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