The 120 volt AC powered LED might use a switching power supply inside the base and the 24 volt might use a buck converter. Either of these can make RFI. Guess it really depends on how it was made and would likely vary from manufactures.
A LED powered direct from DC should not make any RFI.
lenk911
Member
But somewhere there must be an AC to DC converter that may be a radiating power supply unless you're powering with batteries. Then how do you charge them? Its hard to get away from these spectrum killers!
Thank you for the expanded explanation as my question was lacking. I’m thinking about moving my shack to a detached garage. And, the possibility of using 12V or 24V dc for lighting,
I built a 100Ah 24V battery bank. It definitely looks like an abomination against a Bluetti or Jackery but my objective was to learn. It has 24V jacks and also steps down to 12V circuitry to my HF base station, and a buck converter for charging HTs and all things USB. I have both 12V and 24V LEDs.
mmckenna
I ♥ Ø
I've found it to really depend on the quality of the lamp.
I've got 120vac LED lamps throughout my home, and no issues with them on VHF, UHF or 800MHz.
I have 12 volt LED lights on a Polaris Ranger, and they've been fine, no issues with the VHF radio installed in it.
I've had other 12 volt LED lamps that will create some RFI on a hand held VHF radio.
Like many things, you get what you pay for. Cheap Chinese stuff can be problematic.
Use a true linear DC power supply. Stay away from SMPS types as that's where the noise comes from in the majority of cases.
Not necessarily. Keep in mind that an LED is a diode. Many of these lights have no rectifiers. They feed the 120 VAC to a string of LEDs in series (to drop the voltage) and may add a capacitor to take care of the ripple and maybe a resistor to knock down the voltage.
Check out "bigclivedotcom" on YouTube. He tears down lots of LED lamps to show just how many corners the manufacturers are cutting.
Icom used to sell power supplies to accompany their HF radios. I have an Icom PS-125 that I use to power my IC-7610. No RF noise from the power supply. If you build a SMPS correctly, it will be quiet.
All very true.
I have some really quiet SMPS units as well. Including the smaller ones Icom included with some Icom receivers. I think the R75 and R8500 both came with SMPS type supplies. I don't think either of my R8600s came with a power supply at all.
I have nothing high current like the PS-125 though. At least not an SMPS type. I've since moved much of the radio equipment onto a battery system. The batteries are maintained by larger Astron linear supplies.
This works very well but is overkill for most.
I'll still use SMPS type supplies but I sweep them first for noise while they are under normal load powering whatever they came with. If I find them quiet, I'll try them.
I've also had a fair amount of cheap no name (usually) SMPS that fail in a year or less. It's always been a bad capacitor when I open them up. I've never had any of the supplies fail that Icom supplied.
Some of the ones I open up are plain scary when you see how they are built. It's a wonder they work at all.
JustinWHT
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Years ago I bought a string of warm white LED Christmas lights and hung it around the perimeter of my living room for ambient lighting. It had an annoying 30 cycle flicker, telling me it was half-wave AC. I cut off the end and inserted a full-wave rectifier, it looked pretty cool after that.
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