[Hallicrafters] Spiral Fluorescants

[Robert Nickels]

TC Dailey wrote:
>  The transformer runs rather HOT, so that quite a bit of energy is 
> wasted in USELESS HEAT, as opposed to USEFUL heat, which I recover in 
> the shop.
Tom,

I'm not going to argue your CFL feelings with you but this statement 
leaves me puzzled.  Please clarify how heat generated by an incandescent 
lamp is more "useful" than the same amount of heat generated by 
something else.  (CFLs produce about 75% less heat than incandescents).

For those interested,  CFLs use electronic ballasts - pictures and 
schematics can be viewed here:  http://www.pavouk.org/hw/lamp/en_index.html

Each lamp incorporates a DC power supply that drives a pair of switching 
transistors oscillating in the tens-of-kilohertz range (Energy Star 
requires >= 40khz)  to create the AC that drives the fluorescent lamp.  
A typical household these days has dozens of similar switching power 
supplies.  These oscillators must comply with EMC regulations, which in 
the US fall under FCC 47CFR Part 18 - Industrial, Scientific, and 
Medical Devices.  FCC  rules limit the amount of RF voltage that can be 
radiated along the power line to 250 microvolts in the .45 to 30 mhz 
range.  That's not much power and under normal circumstances, will never 
be heard on ham gear.

The easiest way to satisfy yourself that CFLs aren't big RFI generators 
is to do a simple experiment.  Tune in a weak station on a portable AM 
radio, then  hold it up near an operating CFL.  You'll find that you 
have to be within a few inches to hear any electrical noise.   If you 
try this experiment with a shortwave portable, you'll find even less 
noise due to the filtering in the lamp that attenuates the higher 
frequencies even more.

73 Bob W9RAN