Re: Hello,

To: tesla-at-pupman-dot-com
Subject: Re: Hello,
From: Jim Fosse <jim.fosse-at-bdt-dot-com>
Date: Mon, 27 Jan 1997 04:36:34 GMT
Subscriber: jim.fosse-at-bdt-dot-com Mon Jan 27 21:58:23 1997

>Date: Mon, 27 Jan 1997 08:32:35 +1200
>From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
>To: tesla-at-pupman-dot-com
>Subject: Re:Hello, 
>
>Hi Bert (Schumann),
>         Welcome to the list. Here is a preferred way of checking for 
>secondary resonance:
>
>        Place the coil several feet away from other objects. Connect 
>the "hot" lead of the generator directly to the bottom of the coil. 
>Connect a couple of feet of wire to the scope probe and hang it 
>several feet away from the coil. Both the sig gen earth and scope 
>earth are left unconnected. For a good coil, the tune will be pretty 
>sharp. For real accuracy, isolation and *low* coupling of strays in-
>cluding the aerial wire to the secondary are the key. To get anywhere 
>near an accurate unloaded Q measurement, the more coil isolation the 
>better and the generator ouput impedance should ideally be zero Ohms 
>(like a perfect ground - right?). For frequency check alone it is not 
>quite as critical.
>
Bert S;

	Last year at this time, Malcolm had just finished testing 30+
coils (sorry Malcolm if I remember the number to low;) and published a
superb thesis of the Q values for each of his coils. Please note
though; that Malcolm thinks :

> For real accuracy, isolation and *low* coupling of strays in-
>cluding

	means clearing out a 300+ seating lecture room during
christmas break for isolation and testing;)

	(sorry Malcolm, I couldn't resist tooting your horn for that
fine piece of work;);)

Barring that size of isolation, once you have a sharp resonance peak,
try moving your hand toward your coil. If you are closer than 3 feet
away you will see a change due to the capacitance of your hand. This
will show you how sharp of a tune the secondary has and how it can be
influenced by stray objects. Keep this effect in mind when you are
trying to tune your coil to maximum spark. (I just brought my TC back
on line tonight and had the same problem bringing it into tune;)

	cheers,

	jim