[aprssig] APRS: RFI from LED bulbs?

Hare, Ed W1RFI w1rfi at arrl.org
Mon Oct 22 09:43:08 EDT 2018

The ARRL Lab has the ability to make quantified measurements of field strength and conducted emissions from all types of devices.  We use calibrated antennas and spectrum analyzers with CISPR detectors to make accurate measurements in microvolts/meter.  We do not have an anechoic chamber or calibrated open-area test site, but our in-situ measurements can give a very good indication of how these devices would perform if measured under the laboratory conditions used by manufacturers and regulators to authorize devices.

There are probably literally thousands of LED bulbs made today, so we can't act on a simple report that "LED bulbs need to be measured." When they first started coming out, the ARRL Lab bought a large number of them and measured them, finding that the ones being sold by the big box stores at the time complied with the emissions limits.  (Interference is still possible.)  That could change, though, so what we need are model numbers and where they are being sold. The Lab can then buy a couple of the suspect devices, test them, and if there is an apparent emissions-limit violation, ARRL can turn this over to the FCC as a formal complaint. 

Unfortunately, most of the reports we receive do not provide enough information to act. They can range from "LED bulbs are noisy" to "my neighbor had noisy bulbs so we threw them away and replaced them with quiet ones."

Send specific RFI reports, including model numbers of bulbs if possible to:

RFI at arrl.org.

Ed Hare, W1RFI

-----Original Message-----
From: aprssig [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of Robert Bruninga
Sent: Monday, October 22, 2018 9:23 AM
To: aprssig at lists.tapr.org
Subject: [aprssig] APRS: RFI from LED bulbs?

I am hearing reports of RFI from these LED bulbs.  Not just HF, but also VHF.
If you can make any quantitative assessments of such RFI, please let me know.

And the amazing thing is that at VHF you will never notice it because RFI is noise power and it is noise power that keeps a squelch CLOSED.
Manuallly open the squelch and sometimes RFI will show full scale on the S meter yet not open the squelch.  And on my radios, when the squelch is closed, the S meter is inactive and shows 0.

Bob Bruninga, WB4APR

aprssig mailing list
aprssig at lists.tapr.org

More information about the aprssig mailing list