[RFI] Urban noise

[Jim Brown]

On Thu,2/11/2016 7:23 PM, Tom Thompson wrote:
> Yesterday, a friend of mine drove down a main street in the suburbs of 
> Denver using a Perseus radio and a wide band antenna.  On the 20 mile 
> trip we experienced 45 dB of change in band noise due to various RFI 
> sources.

Was this a surprise?  If so, why? Certainly you must have been aware of 
the proliferation of switch-mode power supplies and other noisy 
electronics, some of it part of infrastructure for street signalling and 
lighting, traffic cameras, etc. Those switch-mode power supplies are 
part of virtually ALL modern electronics, whether internal or a wall 
wart or a cord lump, they are used as battery chargers for everything 
from power tools to mobility scooters. And they are used as power 
supplies for low voltage lighting, including track lighting, fancy 
architectural fixtures, and so on. The vast majority of this crap is NOT 
suppressed and much of it lacks an FCC compliance sticker.

All of this noise is radiated by attached wiring, both on the 120V side 
and on the low voltage side.

73, Jim K9YC