On Sun, 16 Oct 2005 10:43:18 -0400, Walter Maxwell
wrote:

We are discussing the Bruene version of the device in which the inductance
derives a sample of the current and C1 derives a sample of the voltage. When C1
is adjusted to obtain the correct voltage for the voltage-current ratio to equal
Zo at that point, such as 50 ohms, the device provides the correct readings when
the line impedance on the load side is Zo. The line impedance Zo on the input
side is irrelevant.

Hi Walt,

You might force what appears to be SWR meter action, but what you
describe above is not sufficient to offer the original accuracy; and
at that point why bother putting a screwdriver in and twisting things?
To accomplish the purpose being discussed takes TWO changes (of the
THREE variables of design) as I have already discussed.

Except under the most fortuitous of circumstances, there is nothing
inside the meter that even closely approaches Z0 - or has to.

As an aside to your comments and directed to the novitiates, any
number of Bruene variants can be found where those variants offer less
than optimal performance. However, quality equipment offers that the
line transiting between input and output connectors and thru the
sensing core IS Z0. This consideration takes so little effort, that
those designs that do not are probably suffering other short-cuts away
from intelligence. This opprobrium goes equally for arguments that
presume there is no line either.

73's
Richard Clark, KB7QHC