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   This section also contains unpublished information that readers have ask about.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 book errata.

Some additional unpublished stuff appears at the end of this page.  
Page Last Updated on April 16, 2019.

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 here.                   (27Feb2018) 
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)
Building Hints for the Simple RF Power Meter    (From QST and EMRFD)   (2 April 15)
Power Meter Updates (regarding June 2001 QST paper with W7PUA.  Also EMRFD.)      (15Aug12)
Mountaineer Transceivers, Old and New     From QST.     (15Aug12)
Progressive 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 PR.
Progressive Receiver Hints and Updates     From QST and some ARRL Handbook editions.   (25Jan14)
      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)
50 Years of Direct Conversion   Regarding QST article with W7WKR in November 1968.  (22 March 19)

EMRFD Related Stuff:

Listed here are a few articles in support of the ARRL book (with KK7B and W7PUA),  Experimental Methods in RF Design.   
A complete book abstract.       (15Aug12)
Designing High Order LC Bandpass Filters from EMRFD       
Mixed Form LC Bandpass Filters (basic theory)              (13May13)
Transformer Coupled LC Bandpass Filters      (16Aug14)
More on the EMRFD "First Transmitter" from Chapter 1.    
An Oscillator Scheme for Quartz Crystal Characterization    
Building Practical Double-Tuned Circuits with EMRFD Procedures   (12Feb13)
The Incidental Multiple-Tuned Circuit      (29June2018)
Another Look at T/R with QRP Transmitters       (3Nov2018)
A Low Noise 50 MHz Amplifier.   A practical circuit using a BF998 SMT dual gate mosfet.   (29Nov15)  
Small Signal Amplifier Design      (15Aug14)
Three articles (mildly 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:
      A Termination 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.   By "unpublished," we mean that they have not appeared in a magazine or journal.

The Two Faces of Q.      (Updated 14April2015)
    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 Q-meter.  
Almost Synthesis       (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.
dB 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)
Simple Quartz Crystal Models: A Review       (2 May 17)
Measurement of transformers used with the EFHW Antenna  
(9 May 17)
Retuning Meshes in a Lower-Sideband Ladder Crystal Filter         (3 Sept 18)
Designing Narrow-Bandwidth Ladder Filters
        (7 April '19)
     Spoiler Alert:  This piece is largely an analytical treatment containing many equations.