[Elecraft] K3: course wanted: Panadaptor 101

[Jack Smith]

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