|Utilitech Pro Soft White LED Bulb|
A recent posting by Phil, KO6BB, to Yahoo Group's ndblist, described his recent search for some LED lamps to replace the CFL's in his shack / radio workbench area. If you have been wondering how much RFI that LED lamps might be producing, you may find Phil's findings of some value.
I had a 60W equivalent CFL in the floor lamp directly over my operating position. I'd tried a 100W equiv one but it was extremely noisy! Also a couple CFLs in the ceiling lamp.
This is a floor lamp with a crookneck at the top and a triangular metal
shade reminiscent of the old style desk lamps, bulb is horiz to the
floor. I've used it for years and like it because it places the light
directly over the operating position work area (keyboard, radios etc).
The actual bulb was about 4.5 inches from the front of the Softrock SDR
receiver (in a plastic case), with the base of the lamp (where the
electronics are) about 7.5 inches (somebody asked about the distances).
This coupled a LOT of RFI directly into the SDR, visible on the
waterfall. For best results when recording and having the light on I'd
slip a 60W incandescent lamp in place of the CFL. The lamp is also
about 16 inches above the operating table, and when listening to ANY
portable radio on the table, if it was in the AM or Longwave band and
using the built in loopstick antenna, got a LOT of RFI from the lamp
(unless the lamp was off ;-)
So today I went down to Lowes (we have a Costco, but I don't have a
card) and looked at their LED lamp offerings. As I expected they had a
large variety of them, from a low cost 3 pack for ~$9.00 for 60W units
to about $18.00 or so each (Sylvania). From what I read here I wanted
to avoid the REALLY cheap ones as some reported them to be 'noisy'.
Also, I wanted to put a 75W equivalent unit in the one over the
operating position, and a pair of 100W equivalent units in the ceiling
lamp. All three had CFLs, and if I walked around the radio room with a
portable radio and the ceiling lamp on I could hear it's 'hash' anywhere
in the room. . .
The ones I settled on were a brand I'd never heard of, "UtiliTech Pro"
soft white, 75W for the bench and 2 100W ones for the ceiling. They
were what I'd call "mid-priced", $8.98 for the 75W and $9.98 for the
75 W one draws 12W and gives 1100 Lumens.
100W one draws 16.5W and gives 1600 Lumens (the pair in the ceiling
should then be 3200 Lumens if I calculated right).
How low is the RFI to my Radios?
75W one over the bench:
NO trace from the lamp electronics visible in the SDR waterfall at
all. With a portable radio on the bench-top, NO audible RFI. Put a
portable radio up to the "bulb" part (light area) and with no station
tuned in can't hear ANY RFI. Move the portable to the base area of the
lamps there is SOME RFI, but I won't be putting the radio that close to
the lamp, move it a couple inches away and the noise disappears.
100W ones in the ceiling lamp, NO audible RFI in the portable when
walking around the room, RFI just barely perceptible right next to the
light wall switch that turns the lamp on, again, audible IF I put the
radio right up to the base of the lamps, not a likely real-world scenario!
Based on the sample of three that I bought and the almost
non-existent RFI from them I'd consider the UtiliTech Pro lamps to be a
good product and suitable for use in the radio room. I consider them
good value for the ~$30.00 I spent for three."
If you have tested anything similar (other brands / models), please let me know and I will add it to Phil's helpful information.
KO6BB's website can be found here, along with some of his homebrew equipment.