Posted by
Ron D'Eau Claire-2 on
May 24, 2007; 6:59pm
URL: http://elecraft.85.s1.nabble.com/K3-course-wanted-Panadaptor-101-tp447983p447996.html
Yep! That's a huge advantage for the K3 in which one can open up the roofing
filter bandwidth for casual, non-critical operation and use a panadapter,
then close the bandwidth down by selecting a narrower roofing filter for
best dynamic range and weak-signal performance and give up the panoramic
display.
Like anything else, getting good results from a great tool requires that it
be used correctly.
Ron AC7AC
-----Original Message-----
Ron D'Eau Claire <
[hidden email]> wrote:
>There's a *huge* performance tradeoff involved in trying to "see" the a
>wide
>frequency range on a 'scope and trying to hear *one* weak signal. In
>receivers with a front end that is "broad as a barn" (including the first
>I.F. in modern receivers), the panadapter can show you many signals within
>that passband, but not all the signals.
That is true to a point which depends greatly on the design and signal
handling capability of both the receiver and of the panadapter. Also the
requirements placed on a panadapter for use in a pile up or for use in the
type of routine band monitoring that I had in mind ( "dead" VHF or HF
bands ) are quite different. In a pile up situation I would not attempt to
"copy" a weak DX signal with the panadapter but do use it in attempting to
find a clear spot among the callers, in which case the panadapter can be fed
via a wide filter branching from but otherwise separate from the main signal
path. A nominal bandwidth of 7kHz appears to cover most pile up situations.
But the true In Passband 3rd Order dynamic range of both receiver and
panadapter must be suitably large to avoid trash being displayed.
73,
Geoff
GM4ESD
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