Posted by
Jack Smith-6 on
May 24, 2007; 12:14pm
URL: http://elecraft.85.s1.nabble.com/K3-course-wanted-Panadaptor-101-tp447983p447984.html
I'll give my views as the designer of the Z90/91 panadapters. Others may
well have different views.
First, I have a definite bias to stand-alone equipment that works
without a computer. And, I have more computers around here than I can
keep track of, going back to a 386 monochrome laptop residing at the
back of a closet someplace. Hence things like the Softrock don't meet my
stand-alone requirement. I have enough trouble finding space on my
operating desk for radios. And, the more computers running, the greater
the likelihood of noise being generated.
How one uses a panadapter depends on the mode of operation used. If you
are a VHF/UHF operator, for example, a panadapter, particularly operated
in waterfall mode, can quickly let you know whether there is any
operation on the band. On HF, a panadapter can show you a pile up
quickly, or in general give you a good idea where the activity is at any
given instant.
For these uses, in my view, a panadapter requires a span of at least 100
KHz, and preferably more. The Z90 has a maximum default span of 200 KHz,
and maximum user-defined span of 250 KHz. In retrospect, I wish that I
had made it 500 KHz, with perhaps 3 KHz resolution bandwidth, as it
would provide a greater overview of most of an HF band (excluding 10
meters, of course).
Another use of a panadapter with frequency flexibility is as a piece of
test gear, suitable for measuring and adjusting carrier and unwanted
sideband suppression and transmitted intermodulation via a two-tone
test. For this, the panadapter must have a minimum resolution bandwidth
of 200 Hz or less.
In my personal opinion, a panadapter with a maximum span of 48 KHz is
less useful than one with a wider span. Others may disagree, as it
depends on how one operates.
My web site has many examples of modulation analysis, transmitter
measurements and the like made with the Z90 panadapter, but these are
generic and are applicable to any panadapter with similar performance.
They can be found linked at the main site www.cliftonlaboratories.com.
Jack K8ZOA
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