Light bulbs and your noise floor the cost of saving power to your receiver Lu Romero – W4LT WCF TechCon 2019

What we will cover Saving power, but making noise in your receiver The legacy of “Dirty Power” harmonics What’s inside those new efficient light bulbs Are LED bulbs any better? Brute force filters, aluminum foil and other “Hammy Fixes” What can we do about it? Will we ever hear S-2 signals again in suburbia? Conclusions and discussion

Comparison of lighting technologies

Comparison of lighting technologies Incandescent bulbs Go back to the days of Edison (and Tesla!) Simply a chunk of wire (simple) Cheap (but becoming hard to find) Ubiquitous (but now getting rare as days go by) Wide and flat spectrum (including UV and Infrared) They get very hot (because light, like heat, is radiation) Just a resistor, so no RFI (just 60hz reradiation)

Comparison of lighting technologies RESISTOR Incandescent bulbs Go back to the days of Edison (and Tesla!) Simply a chunk of wire (simple) Cheap (but becoming hard to find) Ubiquitous (but now getting rare as days go by) Wide and flat spectrum (including UV and Infrared) They get very hot (because light, like heat, is radiation) Just a resistor, so no RFI (just 60hz reradiation)

Comparison of lighting technologies Compact Fluorescent Light Bulbs From the 1930’s Now used more and more Contain Mercury (not good for people) Run cooler than incandescent More equivalent power output per watt used Need warm up time for full output Creates RFI (contains switching transistors) Cheap ones poorly filtered (Not Part 15 compliant) So: What’s inside?

Comparison of lighting technologies Compact Fluorescent Light Bulbs From the 1930’s Now used more and more Contain Mercury (not good for people) Run cooler than incandescent More equivalent power output per watt used Need warm up time for full output Creates RFI (contains switching transistors) Cheap ones poorly filtered (Not Part 15 compliant) So: What’s inside? Lots of discrete parts…

Comparison of lighting technologies Compact Fluorescent Light Bulbs From the 1930’s Now used more and more Contain Mercury (not good for people) Run cooler than incandescent More equivalent power output per watt used Need warm up time for full output Creates RFI (contains switching transistors) Cheap ones poorly filtered (Not Part 15 compliant) So: What’s inside? Rectifiers, filter caps transistors and inductors Generate and radiate if not well designed

Compact Fluorescent Bulbs Use less power, but have higher active parts The active parts need to be well designed to not radiate into free space or back into the powerline (per Part 15… ) Price pressure being what it is, corners are usually cut by manufacturers Generate lots of trash in free space and down the powerline Here is a random CFL in action

Comparison of lighting technologies Light Emitting Diode lighting Latest Technology Last almost a lifetime (solid state device) Emit some heat, but not as much as incandescent Best power to output ratio of all lighting No warm up – instant on performance Intrinsically a diode, DC based function Need rectifier and AC to DC converter to work Cheap ones poorly filtered (Not Part 15 compliant) So: What’s inside?

Comparison of lighting technologies Light Emitting Diode lighting Latest Technology Last almost a lifetime (solid state device) Emit some heat, but not as much as incandescent Best power to output ratio of all lighting No warm up – instant on performance Intrinsically a diode, DC based function Need rectifier and AC to DC converter to work Cheap ones poorly filtered (Not Part 15 compliant) So: What’s inside? Fewer parts than CFL…

Comparison of lighting technologies Light Emitting Diode lighting Latest Technology Last almost a lifetime (solid state device) Emit some heat, but not as much as incandescent Best power to output ratio of all lighting No warm up – instant on performance Intrinsically a diode, DC based function Need rectifier and AC to DC converter to work Cheap ones poorly filtered (Not Part 15 compliant) So: What’s inside? Fewer parts than CFL Full wave rectifier and voltage doubler Poor filtering makes square waves

Light Emitting diode light Bulbs Use the least power, have fewer active parts The active parts need to be well designed to not radiate into free space or back into the powerline (per Part 15… ) Price pressure being what it is, corners are usually cut by manufacturers Generate lots of trash in free space and down the powerline Here are two LED bulbs in action: Cheap and “Expensiver”

Why should we care? All these active circuits contain devices that create square waves Square waves are full of harmonics and these harmonics radiate Active devices, if not filtered and isolated, feed back into the powerline Powerlines both radiate the harmonics and pass the “dirty power” through into connected devices (usually poorly filtered… That cost thing again… Dirty power “multiplies” like rabbits… Additive

Power line issues Clean Sine wave “Dirty” Sine wave

Dirty Power UPS’ are famous for adding crap to the powerline “simulated” sine wave outputs of UPS can wreak havoc on electronics, especially RF systems Not only do they radiate, but they sneak into receiving circuitry, especially “monolithic” SDR type receivers

What can we do about it? Run your house on DC power… But more realistically… Find the offending items and either filter their circuitry or get better ones TANSTAAFL (There Aint No Such Thing As A Free Lunch) Power your receivers (and transmitters) using brute force powerline filters Better grounding your gear sometimes helps (use ferrites on power cords, wrap power cubes in Aluminum Foil with ground wire attached to station ground Build and use Brute Force filters (show mine)

Brute Force Power line filter Here is one built by K9YC Get the parts at local hardware big box store Buy the filters at surplus houses (in Florida, Skycraft Orlando is a GREAT place to get these cheap!) Have a good station ground strategy (single point ground)

Our Goal The relentless pursuit of pure 60Hz sinusoidal sine waves

Light bulbs and your noise floor the cost of saving power to your receiver QUESTIONS and comments?