[Elecraft] [K3] KAT3 and 160 with 40m long doublet

[Wes Stewart]

Don,

So you want to add +j1000 to +j1000 to get zero?

Wes

--- On Sun, 1/2/11, Don Wilhelm <w3fpr at embarqmail.com> wrote:


>   Wes,
> 
> I don't know about the -j501, but Kirchoff tells me that a
> series Xl = 
> j1000 alone will cancel the +j1000 in the shack feedpoint
> (your example) 
> leaving a 50 ohms pure resistive load, no need for the
> shunt element.
> 
> Since the absolute value of the Low Pass L-net impedance
> requires that 
> Rl be less than Rs, I do not know how a Low Pass section
> would provide a 
> match.  The matching section must be a High Pass with
> your values.
> 
> 73,
> Don W3FPR
> 
> 
> 
> On 1/2/2011 10:22 PM, Wes Stewart wrote:
> > Sort of sounds logical.... but it's wrong.
> >
> > Let the load in the shack be 50 +j1000.
> >
> > A low-pass L-net with a shunt Xc = -j501 and series Xl
> = j1000 will do it.
> >
> > Wes  N7WS
> >
> > --- On Sun, 1/2/11, Don Wilhelm<w3fpr at embarqmail.com> 
> wrote:
> >
> >> As you mentioned, the matching range of the KAT3
> becomes
> >> greater as the
> >> frequency is increased.
> >> That fact is often overlooked by many hams. 
> It is all
> >> about the amount
> >> of L and C available in the tuner, but the
> inductive or
> >> capacitive
> >> reactance is really what counts in producing the
> >> match.  If the
> >> feedpoint in the shack has 1000 ohms of inductive
> >> reactance, and the
> >> tuner has only 600 ohms capacitive reactance to
> attempt to
> >> cancel that
> >> inductance, then a match will never happen.
>