[RFI] Replacement For Fluorescent Tubes

[K4RO Kirk Pickering]

One aspect of this discussion is an observation such as "XYZ bulbs don't 
generate noise in my receiver" is fine for stations which are not 
attempting to transmit on one band, while listening on another. For 
multi-op or SO2R contest stations, the requirements are considerably 
more complicated.

Several contest operators have discovered that many LED (and also CFL) 
bulbs become active P/N junctions in the presence of intense RF energy. 
This is a common occurrence in multi-op or SO2R stations. The resulting 
"flooding" of P/N junctions can cause wide-band noise which can often 
wipe out one band, while transmitting on another.

Testing this scenario requires the bulb(s) to be installed at the QTH. 
Then, while transmitting on one band, the other bands must be checked on 
a spectrum analyzer. Such tests are considerably more time-consuming, as 
each band combination must be tested thoroughly. A handheld analyzer 
such as the Tiny SA and a portable sense loop can prove useful for such 
tests.

—Kirk K4RO