Some Technical Stuff
This page deals with errata, updates, and comments on some of our
papers in QST. Some published papers are recent
(well, 21st century) while
others are much older. This section also
contains unpublished information that readers have ask about.
By published, we mean things that have appeared a
journal or book. A section is devoted to articles to support Experimental
Methods in RF Design (EMRFD), ARRL, 2003 (with KK7B and
W7PUA). See our home page for more complete
Some additional unpublished stuff appears at the end of this
Page Last Updated on November 3, 2018.
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. <====
For more information, just click
QST Spectrum Analyzer
(paper in Aug/Sept, 1998, with K7TAU) (24 Apr 17)
Also includes the tracking generator described
in 1999 QST.
Hybrid Cascode IF
Amplifier (From QST. Includes
board layout info.) (26May13)
Notes on the Mark-II
Universal QRP Transmitter (From QST and
some ARRL Handbook editions.) (15Aug12)
Hints for the Simple RF Power Meter
(From QST and EMRFD) (2
Meter Updates (regarding June 2001 QST paper with
W7PUA. Also EMRFD.) (15Aug12)
Old and New From QST.
Receiver PC Layouts From QST and
some ARRL Handbook editions. (9Nov12)
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
Receiver Hints and Updates
From QST and some ARRL Handbook editions.
This section is added to support those folks
continuing to build the PR.
A Lab Microscope
(I finally got one for my own use.) (22June16)
really large historic RF Power Transistor (31July16)
(9 Sept 15)
This regards one
version of the "Universal QRP Rig" that was in Solid
State Design for the Radio Amateur, pp
26-30. Doug DeMaw wrote an article in
the September 1981 QST that used a version of this
transmitter as a vehicle to illustrate some
ideas. The transmitter has
become known as the "Little Joe." This piece on my
web site has some higher resolution scans of the board
to facilitate construction, although I do NOT recommend the project
for there are many designs that are much better now that
we are in the 21st century.
Listed here are a few articles in support of the ARRL book (with
KK7B and W7PUA), Experimental Methods in RF Design.
A complete book
Designing High Order LC
Bandpass Filters from EMRFD (15Aug12)
Form LC Bandpass Filters (basic theory)
report contains several figures generated with LADPAC, a
software package that is no longer available. The
report is still included here, for design equations are
included for series resonator type filters.
This report contains several figures generated with LADPAC,
a software package that is no longer available.
Transformer Coupled LC Bandpass Filters
More on the
EMRFD "First Transmitter" from Chapter 1.
An Oscillator Scheme
for Quartz Crystal Characterization (15Aug12)
Building Practical Double-Tuned Circuits
with EMRFD Procedures (12Feb13)
Look at T/R with QRP Transmitters
Low Noise 50 MHz Amplifier. A
practical circuit using a BF998 SMT dual gate mosfet. (29Nov15)
Coils--a program. (No longer available.)
Three articles (mathematical) discuss small signal bipolar
transistor circuits. The mathematics is not severe, but
just some algebra. The analysis does NOT predict noise
or distortion properties. The 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.
Some Unpublished Stuff:
These are things that I thought might be of general interest.
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
(8 May 15)
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. But 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.) (16Oct2015)
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
designed. (29 Mar 16)
Crystal Models: A Review
of transformers used with the EFHW Antenna
Retuning Meshes in
a Lower-Sideband Ladder Crystal Filter