EMRFD Index, CD, and Software Errata
  (17 April 09)

p500, index.   Add both "IL" and "insertion loss" to the index with "in filters...p3.1,  in receiver roofing filters...p6.50" (10Aug03)

p507, index.  The correct name of VE7QK is Derry (not Jerry)  Spittle.  (24Feb03)

Book CD:  We have found a minor problem with the CD.  When the CD is inserted, a file "articles.pdf" appears on a directory listing of the CD drive.   Double clicking this file causes it to run under the Adobe reader.  Then, any of the articles included on the CD can be viewed by clicking on the listing in the "bookmarks" along the left screen margin.   But the file for W7EL's "Optimized QRP Transceiver" sometimes produces an error message.  It can be viewed if it is the first file called after the "articles.pdf" file is run.   (20Mar03)    [I have not yet checked this one, and it may be fixed on the second printing.   w7zoi 30Sept03]

Computer Design Programs DTC and TTC (from CD):   Both of these programs include an estimation of the insertion loss for the bandpass filters designed by the programs.   This is an estimation based upon the equation given on p 3.10 of the book.  If a better loss number is needed, the filters should be stored with the file|save_as command, and then analyzed with the general purpose ladder analysis program, GPLA.    GPLA is not an approximation, but an exact analysis based on the ladder method, presented in detail in Intro. to RF Design, p51.   See also RF Design Magazine, Sept/Oct., 1983.   Although GPLA is exact, it is limited by the element models used.   That is, capacitors have no series inductance and no loss; inductors have no parasitic capacitance.    The analysis is limited to simple ladders with no mutual elements  other than those between adjacent elements.

The new programs in LADPAC08 no longer contain the insertion loss estimate.   Instead, other parameters are presented that may be of use to the filter designer.


Software Manual.  
I recently realized that many folks have been trying to fight their way through the programs, after they realized that they were even there, without even knowing that a manual existed.    The manual is on the book CD.   Insert the CD and look at the CD with Windows Explorer.   Go into the directory Software and then to the sub directory LADPAC2002.    In this you will fine a long text file, LADPAC2002.txt, which is the manual.   Double click it to open it.   You may wish to copy it to the directory containing the design programs.     (31Oct06)  

Articles on the CD:
It is not our intention in general to offer any updates or errata for any of the magazine articles on the book CD except in some special situations.   A special circumstance that we might consider is if the subject is of general fundamental interest.

(This item was "fixed" by including the program "Padcap08.exe" with the other software.) Article #30.   Appendix to "A Progressive Communications Receiver," QST, November, 1981.    This presents equations to calculate the fixed capacitors needed when a variable capacitor is padded to behave as if it was a smaller value.   A typical application might be the use of a 365 pF variable to tune over a small frequency range where a variable of just a few pF is really needed.    An error is present in Eq. 3. of the appendix, p21.   The first term on the right hand side of the equation should have a subscript of  U rather than V.     The complete equation set is given here:
 Fundament units (Hz, Henry, Farad) are used.
 (24Aug06)