ORIGINAL MESSAGE:
On Wed, 26 Jan 2011 16:36:50 -0500, Gene May <gene-may@hotmail.com>
wrote:
> As I understand, it is difficult to impossible to get coupling coefficients
> higher than about .3 using coils that would be compatible with the voltages
> and currents associated with an output of 1.5 KW. Comments, please?
REPLY:
I don't know a lot about these, but I recall that coupling is easier
with a higher tank Q. Makes sense because higher Q means higher
circulating current and thus a stronger magnetic field.
Also, coupling is much easier if the link is made series resonant at the
operating frequency. This reduces coupling of harmonics too. In the old
days it was common to make the link fixed and adjust the coupling with
the series variable capacitor. That simplifies the mechanical a bit. I
did it that way on a six meter amp when I was first licensed, worked
fine. That was single-ended though, not push-pull.
Hope this helps.
73, Bill W6WRT
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