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

2. 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

3. Comparison of lighting technologies

4. 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)

5. 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)

6. 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?

7. 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…

8. 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

9. 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

10. 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?

11. 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…

12. 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

13. 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”

14. 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

15. Power line issues
Clean Sine wave
“Dirty” Sine wave

16. 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

17. 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)

18. 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)

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

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