Geoffrey S. Mendelson wrote:


If it produces noise that interferes with an AM radio, it will interfere
with a 60kHz clock. CFL's are especialy bad.


This has not been my experience. I have CFLs everywhere except in the
fridge and in the oven. They don't make any significant noise. My
neighbors' lamp dimmers and motion detectors produce way more noise than
my RF light bulbs.

I have an "atomic" clock on my bench at work, inside a steel framed
office structure, inside a big tilt-up warehouse, and that clock manages
to set itself about 3 times a week.

GPS receivers cannot run for a year on a single AA battery.