Understand what these compact florescent bulbs really are ... a small,
tightly coiled, florescent tube with an *electronic ballast*. The
electronic ballast is nothing more than a small, cheap switching power
supply to generate the high voltage necessary to fire the tube.
When a CFL fails it is invariably the electronic ballast that goes -
often breaking down (arcing internally) under the high voltage.
Most of the bulbs these days are quiet in normal operation but once
they start arcing internally - particularly the bypass and filter caps -
it becomes a small spark transmitter with a very large antenna.
73,
... Joe, W4TV
On 3/25/2014 1:37 PM, Steve wrote:
these CFL bulbs can generate some strong RF
noise just before going out.
Mack - had a similar issue here several years ago...s9+ buzz throughout
the longwave band for a month. I live on an island with very few winter
neighbours and eventually traced the source (which was radiating nicely
via the powerlines) to an unoccupied summer residence, but still was not
100% certain as the signal was so loud from all of the 11 home's drop
lines on the local grid. When the owner returned I had him pull the main
breaker and sure enough the buzz stopped. It turned out to be a
burned-out CFL bulb in the crawlspace that they left on to discourage
any sea otters from trying to get into the space during the winter. The
bulb was heavily charred and parts of it had already melted yet it
continued to radiate a strong signal. Needless to say they were glad
that it hadn't set their place on fire and have since stopped using this
type of bulb.
Steve / VE7SL
Mayne Island, BC
WEB - "The VE7SL Radio Notebook": http://members.shaw.ca/ve7sl
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
_________________
Topband Reflector Archives - http://www.contesting.com/_topband