Re: [Amps] *** SPAM *** Re: Antenna traps

[R.Measures]

On Dec 16, 2005, at 6:58 AM, Peter Chadwick wrote:

> Lets consider my original proposal, a parallel tuned circuit.
>
> Working Q is given by (let's assume an infinite component Q for the 
> moment) XL/RL. That value of XL can therefore be made anything we 
> want.
>
> The simplest approach is now to tune the inductor to resonance with a 
> shunt capacitor, and we can link couple in. Vary the link (i.e.the 
> effective leakage inductance)  and voila!
>
> The link could be substituted by a suitable large value of inductance 
> between the input and the top of the tuned circuit. The value of the 
> inductance depends on the impedance of the step up ratio that we want: 
> we'll have to readjust the tuning capacitor, but we will still have 
> the Q fixed by the ratio of the inductance to load impedance. Or we 
> can even tap the tx at the bottom of the tuned circuit, and adjust the 
> tap point for a match - and then we have a tuned auto transformer.

The potential fly in the pie is that, especially for a lengthy 
inductor, not all of the magnetic flux lines in the primary couples to 
all of the flux in the secondary.   Thus, a tapped L arrangement is not 
necessarily a simple auto-transformer

> The higher the amount of capacitance, the higher the Q.
>
> Peter G3RZP
>
>  

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org