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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