Hi Roelof, Gary and others,
Gary wrote:
On the top menu bar click
"View/Windows" then "Spectrum Lab components" & you will get a block
diagram, look for box with ? in it on a connection between L4 & L5 (next to
a green triangle), click this box & point at "Automatic Gain Control" at the
bottom of the list, choosing/setting different values may help the
situation.
Wolf said this is not a visual gain control like those in Argo & Spectran so
may only have a minimal effect, tried it & believe it did help. The problem
with visual AGC is that it not only reduces the level of visual noise on the
display it also reduces the displayed signal.
Thanks for the explanation Gary, it is correct. The downside with the
AGC ("visible" or not) is, you don't notice what causes the signal to
get weaker on the screen : Is it, because the signal voltage drops, or
because the broadband noise level increases ?
Without an AGC, you can clearly see the screen getting lighter. And if
the (wanted) signal gets darker, you know its voltage drops. For
propagation analysis, you want to observe the "absolute" voltage, so
better switch the AGC off (this applies to all kinds of AGC's, hard- or
software).
Furthermore, if you want to plot the field strength in a graph (like
CT1DRP and some others in this group do), the AGC *must* be turned off,
otherwise the "dBuV / meter" readings get useless.
Best regards,
Wolf DL4YHF .
|
