[RFI] Variable Color LED Grow lights

HP pfizenmayer at q.com
Mon Jan 29 01:42:24 EST 2018

Anyone have any experience with RFI suppression 
of these variable color LED grow lights ? At first glance it seems it 
should be easier to suppress than sodium vapor or metal halide lights . 
The LEDs appear to be driven with something less than 24 volts and constant current sources - and the AC to DC conversion appears to be switching mode 
but the changing from driving one set of LEDS to another seems to have strange frequency compinents -not just the basic switcher which appears may be 19.1 khz . 

I am hoping someone else has encounterd these type grow lights . 

An AC line filter would be a first shot but how effective it would be would depend on the run the supply/programmer to the lights . 

One of these appeared within 50 feet of my antennas and is apparent from 160 thru 10 meters . I can see the color thru the window and it slowly varies from a deep blue/purple to red and back - blue/purple in about 3 second cycles .From what I read on the web , thats what the plants need - and you can get more specific dwells at different colors at different periods of growth . 

Using peak reading on a P3 , on 20 M the peaks of the "sawtooth" 
vary from 6.5 khz spacing at 14211.8 increasing to 20.1 khz at 14245.8 
then start decreasing to between 12.5 and 13.5 at 14336.9 to 14426.6 
there is an abrupt change from 14303.3 of 19.9 khz to next step at 14336.9 which 
is 12.8 khz . This AM I checked on 160 and the spacing seems to be 19.1khz In Interesting , it almost looks like they have some filtering for the AM broadcast band 
as I cannot hear it at all above local AM stations with a little Sony Walkman 
about 20 feet away . So it appears they have eliminated the "you are broadcasting to anyone with a car radio you are "growing ".which used to be a tool . 

This one started out with about 4 hours from around 6:30 to 10: 30 PM - but today it has been on all day so guess they are into the 12 hour period. 

Hank K7HP 

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