Re: No Subject


You said:

I built a small coil some time ago which produces 3" sparks. There is no 
shielding of any description around the unit. Now I find that when I operate
near any 'consumer' electronic equipment, it messes around with their

Example - My Hitachi TV will switch on to channel 3 when the coil is running
several feet away.

I have read many times about how small coils shouldn't be an emission problem
so I can't understand what is going on. The coil runs on a ~200W supply, and
is an old design which is an absolutely basic circuit - xformer, cap, gap and


I think what you are seeing is problems with conducted RF energy back through
the transformer and into your AC wiring.  You can fix this by adding RF
chokes in series with the transformer output lines and by adding bypass
capacitors across the output of the transformer.   I made a recent posting
about this in more detail.  If you can't find that posting let me know.  Are
you using a neon sign transformer?  Is the case (center tap) tied to your RF
ground?  What are you using for an RF ground?  It should be a dedicated
ground that is isolated from your AC breaker box ground.

Ed Sonderman