[Elecraft] K3: course wanted: Panadaptor 101

[Geoffrey Mackenzie-Kennedy]

Ron D'Eau Claire <rondec at easystreet.com> 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