Notes regarding the 1998 QST
Spectrum Analyzer
Updated on 22
Jan 2020, Revised on 18 March 2021
I should have known.
In early 2020 I was extracting old files from the w7zoi
webpage in an effort to gain more room for new
things. The part of the web page relating to the
1998 QST paper that K7TAU and I coauthored (QST, August and
September, 1998) had not seen much activity in two years, so I
shaved it down. But now, in late 2020 and
early 2021, I'm seeing renewed interest in the spectrum
analyzer project, including some folks who have actually built
one. (How gratifying!) So, I'm pulling some
of that old material back into this
section. Those building this spectrum
analyzer, or a similar one should be sure to take a look at
the refinements that we included in Chapter 7 of Experimental
Methods in RF Design.
While this material relates specifically to
the 1998 QST system, many of the items may have broader
application.
RCA Plugs and
Sockets
This excellent piece from K7NHI is of
general interest for those not wishing to specialize in SMA
connectors.
VHF LC
Bandpass Filters
This
module is an improvement over the one we used in the 1998
article. There's more shielding, including a lot
between filter resonators, but it's worth it.
A Simple VHF LC
Bandpass.
This
circuit was one I built long ago, but the circuit may still
be a useful element in an experimenter's bag of tricks.
Other variations
for the VHF Bandpass LC Filter
This
note describes some experiments by VU2ESE and K3NHI.
VHF
Crystal Oscillator Experiments
Experiments led to a refinement for the 100
MHz and 110 MHz 5th overtone oscillator used in the spectrum
analyzer.
Early
Spectrum Analyzer Updates and Mods
This outlines some of the earliest activity,
including hints about adopting other narrow filters.
Later SA
Refinements
The
saga goes on.....
Spectrum
Analyzer Operation with a Digital Storage Oscilloscope
Triggering and similar details related to a DSO.
Bottom line: It's the only way to go.
Tracking Generator
Modifications and Recommendations
Bob Kopski, K3NHI, and John Lawson, K5IRK, came up with a
modification for the tracking generator going with the QST
SA. Great work.