[Elecraft] OT: LED Light Bulbs

[Bob McGraw K4TAX]

One thing observed at our repeater location is that the CFL was quiet until the the transmitter was on the air. It then generated noise.  In a simplex condition it wouldn't be observed. But in a duplex operation or multiple receiver situation it becomes an issue.  Replaced by a LED with lessened issues. 

Bob, K4TAX


Sent from my iPhone

> On Oct 21, 2017, at 11:21 AM, Jim - N4ST <Hamshack at N4ST.com> wrote:
> 
> I have noticed the background noise level growing on the HF bands, and for me, especially on 18 Mhz.  I need to declare war on RFI and find out what is causing this.  I did carefully checkout some Walmart "100 W" LED lights before committing to them and they were fine.
> 
> 
> _________
> 
> 73,
> 
> Jim - N4ST
> 
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Bob McGraw K4TAX
> Sent: Saturday, October 21, 2017 11:32
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] OT: LED Light Bulbs
> 
> Makes me wonder if at all or how frequently production lots are evaluated to determine if they are in FCC Part 15 compliance.
> 
> Otherwise, the approach "we evaluated one production lot, deemed it passed" {a.k.a - I saw it work once, ship it}  and then produced a million or so afterwards including those with some engineering changes and cost down changes.
> 
> Guess I need to power the radio from the tractor battery and dump the main breaker in the house to see how much the noise changes.
> 
> 73
> 
> Bob, K4TAX
> 
> 
> 
> On 10/21/2017 9:48 AM, w4sc wrote:
> 
> > An observation:
> 
> >
> 
> > I too had RFI from LED lights, but the interference was to OTA television, Channel 10 (192-198 MHz) DTV.
> 
> >
> 
> > Not all LED bulbs are created equal in this regard, RFI reduction / elimination.  The RFI was generated in this case by the SMPS integral to the bulb.
> 
> >
> 
> > The offending bulb is Utilitech part # 5DG6 (printed on the bulb) and is ‘C  UL  US’ listed, purchased from LOWEs.
> 
> >
> 
> > I have a overhead fixture that was populated with four 800 lumen (60w?) bulbs, 2 being Utilitech, and 2 Sylvania OSRAM.
> 
> >
> 
> > By removing the bulbs and observing channel 10 reception, the offending bulb was determined to be the Utilitech.
> 
> >
> 
> > I replaced the the the Utilitech bulbs with Sylvania OSRAM, and the RFI on channel 10 OTA was eliminated.
> 
> >
> 
> > The Sylvania OSRAM part number used is LED8.5A19/DIM/0/827/G5/RP as printed on the box UPC, and were purchased from LOWEs also.
> 
> >
> 
> > NOTE: There may be interference from Sylvania OSRAM bulbs on other frequencies.  LED bulbs are required to meet FCC Part 15 FCC, Class B regulations.
> 
> >
> 
> > YMMV
> 
> >
> 
> > I have not seen a comprehensive report or article that unveils “good” vs “bad” LED bulb manufacturer and part identification as far as RFI emissions across the spectrum.
> 
> >
> 
> > Ben W4SC
> 
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