I have read of beating but do not know if this is what 
I am experiencing.First if needed, here are my coil's
9kv-at-30ma neon transformer.
secondary: 4" prepared PVC 15" wind length 808 turns #21.
primary: 9 turns 3/16' copper tubing conical form.
Richard Quich type cylindrical spark gap
4" x 14" o.d. aluminum ducting torroid
.01uf -at- 15kvdc cap (wimpy studs; probably made to be a 
filter cap - gets hot quick so shorts runs; can't wait until my
CP caps arrive!)
Recent D.C. Cox type protection circuit as experiment
though I like what Richard Hull posted recently! I do
run mine for short intervals so no determination can
be made.

Okay my observation:

The Richard Quick spark gap has 6 gaps (7 tubes)
If I use only 5 gaps (6 tubes), I get not the longest
spark but it is smooth and fluidy. When I bring a
grounded screwdriver to the torroid I get an evenly
illuminated arc. 
When I employ the last gap (6 gaps), I get sparks
of considerable longer distance but the sparks look
and sounds very raspy, not smooth and not fluidy.
When I bring the grounded screwdriver to the
torroid now, I get a section in the middle of the
arc that is much brighter than the majority of the
arc. The illumination is not evenly dispersed.
I have tried many tunings and coupling adjustments
with both setups but the main observation still is
prevelant. I do not know if this is 'beating' or not.
I also wonder about my current cap since it has
small studs as if were designed as a filter cap and
gets hot quick. 
Does this symptom sound like something others
have experienced?
Would appreciate feedback :)
Thanks all,

Bob Schumann
* If you understand, things are just as they are.
* If you do not understand, things are just as they are
. *