New Pseudo-toroid Available

Hello coilers !!

I have made up a new type of spun aluminum pseudo-toroid.  This 
unit is simply flat at the bottom and top, with a curved edge.  Sort of
an oblate spheroid shape.  It is made to the same high level of quality
and surface finish as my other true toroids.  It is formed from two half-
shells, expoxied together the same way as my other toroids.  From a 
side-view, it looks exactly like a normal toroid.  This unit is 3.5" thick
by 11.5" diameter, and I am offering them for sale for $68 postpaid
in the US.  The center mounting hole is 1/2" diameter.  The cost is
lower because fewer steps are needed to make this unit.

These units can be used for a number of applications; as a normal
toroid, as a corona shield placed below the main toroid above the
secondary, or as corona shields to be placed at the bottom and/or
top of a magnifier resonator.  When used below a main larger toroid,
it can be used to increase the total topload capacitance, and thereby
increase the sparklength in a suitable TC set-up.  For example, when I
placed a 3" by 10" toroid below my 4" by 13" toroid on my TC, the 
spark length increased from 51" to 58" using the same power input.

When this "toroid" is placed below a main toroid, or on a magnifier
as a corona shield, the fact that it is not a true toroid is not noticeable,
if the coil form is at least 6" in diameter or so.
In a way, it is better than a toroid because it is flat and simply rests
on top the the coil form.  This unit therefore serves as a less expensive
alternative to a true toroid in these applications.  This unit can be used
in place of a normal toroid however if desired, again as a less expensive
alternative to a true toroid shape.

These units should also be very useful for serving as the bottom toroid
when varying the separation between two toroids as a method of TC

Of course my other true toroids are still available for $32 for the 1.5"
by 6" size, and $126 for the 4" by 13" size.

These toroids (but not the pseudo-toroid) can be seen at my 
webpage at:


John Freau
49  Thiem Ave
Rochelle Pk,  NJ   07662