@muleface, I'm a big fan of your dedicated research in the 'COB Users:Lettuce Grow Challenge', thanks for allowing me to watch and learn!
...and you are absolutely correct about the intensity dropping off unfortunately quickly
Have you taken any light level readings under them? Either PAR or Lux?
There's surprisingly not much difference in accuracy between a PAR reading on an Apogee and a LUX measurement on a decent LUX meter when it comes to measuring LEDs
https://www.apogeeinstruments.co.uk/light-intensity-measurements-for-light-emitting-diodes-leds/
They word it politely, but if you look at their sensor's response as opposed to the PAR spectrum(2nd graphic down) and then their admitted error% in the chart above, you can see what I mean. I hope
So while it's not in PAR, I have done some measuring
This is what I want to see; readings at the tops or canopy.
Thanks for your strippin & scroggin' thread GG, i appreciate the info in it and the good nature of it...I'm still subbed up
Well I usually just sponge info@RIU, but apparently this is a chance for me, myself &I to give something back to the fine folks here.
As requested - note that I do not conduct 'experiments' in a scientific nature. I smoke ganja heavily and, this time, fiddled with a ruler, LUX meter, pencil and paper.
-Testing Equipment:
Taken with a consistant, 200,000k digital LUX meter
-Testing Area:
27 x 18 inch cabinet (3.375 sq feet)
-Light configuration as tested: (will try and get a pic up soon of it, been BUSY)
8 x 560mm EBs @3K
HLG-120H-C700A @700mA
@700mA, units expressed as LUX
.5" 100K
1" 65K
1.5" 60K
2" 55K
3" 50K
4" 42.5K
6" 35K
6.5" 30K
-Further away than that, why bother. This IS a flowering cab and I'm about that PPFD
Strips are only 0.75" apart, 4 on each 'side' with a 2" gap in the middle. There are more strips than gaps obviously as is. It's a pretty dense diode arrangement.
I could have driven them higher and designed the fixture accordingly, however i'd prefer to add diodes and drop drive current personally