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   This section also contains unpublished information that readers have ask about.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Some additional unpublished stuff appears at the end of this page.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 May 9, 2017.

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.                   (18 Aug 2016) 
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)
A really large historic RF Power Transistor      (31July16)
Regarding "Little Joe."               (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.

EMRFD 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       (15Aug12)
Note:   This 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.
Mixed Form LC Bandpass Filters (basic theory)              (13May13)
Spoiler Alert:   This report contains several figures generated with LADPAC, a software package that is no longer available.
Transformer Coupled LC Bandpass Filters      (16Aug14)
More on the EMRFD "First Transmitter" from Chapter 1.     (15Aug12) 
An Oscillator Scheme for Quartz Crystal Characterization    (15Aug12)
Building Practical Double-Tuned Circuits with EMRFD Procedures   (12Feb13)

A Low Noise 50 MHz Amplifier.   A practical circuit using a BF998 SMT dual gate mosfet.   (29Nov15)  
Coils--a program.    (No longer available.)     20Jan17
Small Signal Amplifier Design      (15Aug14)
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:
      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. 
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)