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So, LOGMAG is logrithmic magnitude (I assume) but which parameter/signal is it displaying logarithmically?
Is it forward or reflected?
I don't see it mentioned in any of the documentation.

On Tue, 22 Oct 2019 at 20:17, Nigel Gunn, G8IFF/W8IFF <nigel@...> wrote:

So, LOGMAG is logrithmic magnitude (I assume) but which parameter/signal is it displaying logarithmically?
Is it forward or reflected?
I don't see it mentioned in any of the documentation.

Each trace is associated to one of the two channels; CH0 is S11
(conventionally called Port 1), CH1 is S21 (conventionally called Port
2).
Which trace goes with which channel is displayed on the screen - at
least with the recent firmware from edy555 that I'm using.

It might become clearer if you go to Display > Trace and turn off all
the traces.
Then select one trace and watch what comes up on the screen.
In my case, trace 0 is CH0 LOGMAG.

Trace 0 and 2 are for CH0; trace 1 and 4 are for CH1.
73
--buck

On Wed, Oct 23, 2019 at 03:17 AM, Nigel Gunn, G8IFF/W8IFF wrote:

LOGMAG is logrithmic magnitude (I assume) but which parameter/signal is it
displaying logarithmically?

This is magnitude of gamma (complex reflection coefficient).

gamma = re + j*im

logmag S11 = sqrt(re*re + im*im)

phase S11 = atan2(im, re)

there is mistyping :)

corrected:

linear magnitude S11 = sqrt(re*re + im*im)

logmag magnitude S11 = 20 * log10( sqrt(re*re + im*im) )