Re: Grid Dip Oscillator

From: 	Alfred A. Skrocki[SMTP:alfred.skrocki-at-cybernetworking-dot-com]
Sent: 	Sunday, November 30, 1997 9:09 AM
To: 	tesla-at-pupman-dot-com
Subject: 	Re: Grid Dip Oscillator

On Sunday, November 30, 1997 1:55 PM Malcolm Watts
[SMTP:MALCOLM-at-directorate.wnp.ac.nz] wrote;

> Perhaps I ought to clarify what I was trying to say as it appears
> to have been misconstrued in several quarters....
> > > Not really. You have to get too close to the secondary coil to
> > > use the thing and that seriously affects frequency.
> >  
> > Not so, Malcolm! The grid dip meter was a very effective
> > instrument to tune tank circuits with, the trick was learning how
> > not to over couple to the meter. When loosely coupled to a coil a
> > dip meter has no noticeable effect on the coils resonant
> > frequency.
> All the GDOs I've ever used are hand held beasts. The point I was
> attempting to make was that in using one, *you* have to get
> physically close to the coil and as we all know, that certainly
> *does* alter the coil's characteristics markedly. Having said that,
> perhaps there are GDOs one can operate remotely ???

In theory your correct but in practice a properly used Dip meter
won't interefere with tuning a coil or measuring it's resonant
frequence. There is a simple circuit I remember in a back issue of
Popular Electronics (in the 50's) that used a signal generator, an
inductor, a diode and microamp meter as a Dip meter and only the
coil needed to be in proximity to the tuned circuit to be measured,
but using even the hand held dip meters I've never experienced any
interaction problems.


                              \\  ~ ~  //
                               (  -at- -at-  )
                           Alfred A. Skrocki
                             .ooo0   0ooo.
                        -----(   )---(   )-----
                              \ (     ) /
                               \_)   (_/