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    This section also contains unpublished information that readers have ask about.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 knows about the Internet!    Also see EMRFD Errata for  Experimental Methods in RF Design (EMRFD), ARRL, 2003 (with KK7B and W7PUA).   Scroll down for filter design information, including some quartz crystal related things.


Page Last Updated on November 4, 2023....


General Interest and QST Related Info:


Free Semiconductors from KE6F.     Lots of good stuff is available.    For more information, just click here.        (20June2023)

QST Spectrum Analyzer (paper in Aug/Sept, 1998, with K7TAU)        (18March2021)

     Also includes the tracking generator described in 1999 QST.

Hybrid Cascode IF Amplifier    (From QST.  Includes board layout info.)    

Progressive Receiver PCB Layouts    From QST and some ARRL Handbook editions.  

This section presents the PC board layouts generated by K5IRK for our Nov 1981 QST paper on the Progressive Receiver. Although some folks continue to sell these boards, they don't include layout information.
A Simple Modification to a Classic Transmatch  


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      

The Incidental Multiple-Tuned Circuit      

Another Look at T/R with QRP Transmitters       

A Low Noise 50 MHz Amplifier.   A practical circuit using a BF998 SMT dual gate mosfet.   


Small Signal Amplifier Design     

Three articles (mildly mathematical) discuss small signal bipolar transistor circuits.   The three 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.

     Termination Insensitive Amplifier with AGC     update 27oct2021      

An Audio Feedback Amplifier for DC Receivers   a.k.a.  AFTIA       (New April 2021)

Bypassing and Decoupling--Thoughts and Modeling       



Some Unpublished Stuff: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   By "unpublished," we mean that they have not appeared in a paper magazine or journal.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 Q-meter.   

Almost Synthesis       

       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.   

dB 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 designed.      

Extract scattering parameters in a SPICE analysis.    This is an old one that continues to be requested.     

Experiments with a Single Vacuum Tube Regenerative Receiver         (29April2022)
Synthetic Spurs added to a carrier    


Filter Design and Crystal Things:


9 MHz Filters with Inexpensive Crystals     

What's this 30 pF Stuff?       

An Oscillator Scheme for Quartz Crystal Characterization     

Designing Narrow-Bandwidth Ladder Filters       

        Spoiler Alert:   This report is a general discussion that is long and is full of equations.

Retuning Meshes in a Lower-Sideband-Ladder Crystal Filter        

Simple Quartz Crystal Models:  A Review           

Mixed Form N=3 LC Bandpass Filter Design Equations    

Practical 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.