[time-nuts] CFL's and WWVB/GPS

Mark Amos mark.amos at toast.net
Fri Aug 10 08:38:46 EDT 2007

I use mostly CFL bulbs in my house - one in my office/radio shack about 2M from a WWVB wall clock (mounted 
on a northern wall, here in Ohio, no external antenna).  This is about the same distance from the GPS 
antennae, but they are above on the roof (on a metal ground plane).  While I don't have equipment to measure 
the noise at WWVB, the clock continues to tick in sync with WWV and my GPS disciplined clocks.  I've never 
had any problems (at least while I was watching) with the GPS devices losing sattelites, S/N problems, etc.

I only use Phillips bulbs, though and none of them are older than about 18 months, so maybe the newer bulbs 
really are less noisy than the old ones.  I haven't seen any evidence of noise difference on the 160 or 80 
meter ham bands with the lights on or off.  My antenna for HF is about 4M from the house.

There was some rather vitriolic dialog on the "glowbugs" reflector a month or so ago - eventually it 
degraded into green-bashing and urban myths about mercury poisoning and explosive bulbs...

So far, I haven't seen any of these problems, but maybe I've just been lucky (or just don't have the 
sensitivity in equipment necessary to experience them.)


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