Some Technical Stuff
This page deals with updates and comments on some QST
papers. This section also contains
unpublished information that readers have ask about. By
published, we mean things that have appeared a journal or
book. Who know about the Internet! A section
is devoted to articles to support Experimental Methods in RF
Design (EMRFD), ARRL, 2003 (with KK7B and
W7PUA). A section at the end relates to filter
design, including some quartz crystal related things.
Page Last Updated on April 23, 2021.
General Interest and QST Related Info:
Free Semiconductors from KE6F.
Bob has some BUZ104 Power MOSFETs as well as the small signal BF998
dual gate MOSFETs, and much more.
For more information, just click
QST Spectrum Analyzer
(paper in Aug/Sept, 1998, with K7TAU)
Also includes the tracking generator described
in 1999 QST.
Hybrid Cascode IF
Amplifier (From QST. Includes
board layout info.)
Receiver PC Layouts From QST and
some ARRL Handbook editions.
This is not a discussion, but is a collection
containing the PC board layouts. These are the boards
originally designed (by K5IRK) that were used in the original QST
receiver for November, 1981. The boards have
been sold by some manufacturers here and there, and may even still
be available. However, the folks selling
boards no longer bother with the template information.
These are old, single sided boards, but they worked for the
EMRFD Related Stuff:
Listed here are a few articles in support of the ARRL book (with
KK7B and W7PUA), Experimental Methods in RF Design.
Transformer Coupled LC Bandpass Filters
Look at T/R with QRP Transmitters
Low Noise 50 MHz Amplifier. A
practical circuit using a BF998 SMT dual gate mosfet.
Three articles (mildly mathematical) discuss small signal bipolar
transistor circuits. The three articles are:
Insensitive Amplifier for Bidirectional Transceivers
(with Bob Kopski, K3NHI)
The Feedback Amplifier
with a Simple Model
(This is the math in greater detail for the other two articles.)
Transistor Models and the Feedback Amplifier
This one includes some measurement data.
Audio Feedback Amplifier for DC Receivers
(New April 2021)
Bypassing and Decoupling--Thoughts
Some Unpublished Stuff:
These are things that I thought might be of general
interest. By "unpublished," we mean that they have not
appeared in a paper magazine or journal.
The Two Faces of Q.
This is a discussion about the Q of LC
resonators, and the Q of the individual L and C elements. We
normally measure the Q of a complete tuned circuit. This
is the result of the Q of both the L and the C in that
circuit. This report discusses the measurement methods
that can be used, the way the Q of L and C combine, and some
measurements we have done on a variety of components. A
variety of measurement tools have been used including a HP4342A
This is a discussion of a
frequency synthesizer built to control a traditional superhet
receiver or transceiver. It is a one-on-one PLL design,
so the phase noise performance is
reasonable. Additional features make it
handy for general purpose applications. No special
ICs are used, and it is dirt cheap. This is
not a "DIY" type project to be copied. Rather, it is a report
about an experiment that we did.
versus dBm This
is a discussion of the mathematics related to the
decibel. (We think that the math does matter.)
JFET101 This tutorial examines
the junction field effect transistor, starting with a simple
model of a piece of silicon. After
discussing the behavior of the element, it is
applied. First, biasing is
presented. Then some amplifiers are
scattering parameters in a SPICE analysis.
This is an old one that continues to be
Filter Design and Crystal Things:
9 MHz Filters
with Inexpensive Crystals
30 pF Stuff?
Oscillator Scheme for Quartz Crystal Characterization
Narrow-Bandwidth Ladder Filters
Spoiler Alert: This report is a
general discussion that is long and is full of equations.
Meshes in a Lower-Sideband-Ladder Crystal Filter
Crystal Models: A Review
Form N=3 LC Bandpass Filter Design Equations
HF Bandpass Filter Tuning
This takes one past the computer design.
After the design, you alter values, insert trimmers, and
tune. This tells one how to do it.