With a feedback driven system, i don't see proximity effects changing
the operating parameters so much as to not make it work, assuming of
course you are driving it with feedback.
Dan
I recently noticed that the ceiling height and material can make a
significant difference in a coil's secondary frequency.
Case in point - I was trying to get my DF-DRSSTC working. I couldn't
get it to break out properly and it was drawing too much current. I
took the coil over to a friend's house and it was working well - got
18" arcs to a ground rod - with no change in the coil configuration.
What was the difference? My friend said his shop which has a flat
metal roof, suppresses the operating frequency of his coils. When he
moves them outdoors, they have to be retuned. When I was trying to
run this coil before, I was in my garage which has no "ceiling" only
open rafters up to the roof.
In playing with parameters in JAVATC, I see a noticeable change
between an 8 ft ceiling and a 12 foot ceiling. I don't see anything
in the program that inputs the material type for the ceiling. I would
think a non-conductor like gypsum wallboard would have less effect
than a flat steel roof. Maybe Bart could shed some light here.
The bottom line for me is to accurately model the room envelop when
running a TC modeling program. Also, if you relocate the coil - say
from in the garage to out on the drive way - expect to have to retune
(possibly reconfigure).
Jim Zimmerschied