[Elecraft] Corrections on Island Pad Capacitance; Zverev and Audio Transformers

[Jack Smith]

I've made small corrections to the island pad capacitance computations 
to reflect the copper foil thickness data provided by Grahan, KE9H. The 
computed and measured island capacitance does not change, but some 
intermediate results do. More details at 
http://www.cliftonlaboratories.com/Prototyping.htm

I've mentioned the classic book on filters, /Handbook of Filter 
Synthesis /by Anatol I. Zverev, but its current cost has been in the 
stratosphere. I received an E-mail from Brad, AL4T recently informing me 
that a lower cost ($58 at Amazon) paperback edition of Zverev is now 
available. If you have any interest in filter design, this book should 
be in your home library. Don't be put off by the equations--there's 
plenty in there that can be understood with high school math and the 
effort of plowing through the more complex bits are very rewarding. I 
highly recommend this book. (When I checked early this year, only the 
hardback edition was shown, at nearly $300, so a $58 paperback edition 
is a huge savings.)

Finally, for those interested in SoftRock receivers, I've added measured 
data for a Bourns 600 ohm : 600 ohm isolation transformer, 
LM-NP-1001-B1. This can be used reasonably well for 24 KHz purposes and 
will work up to 100 KHz if the termination impedance is carefully 
selected. More details at 
http://www.cliftonlaboratories.com/softrock_lite_6_2.htm.

Jack K8ZOA
www.cliftonlaboratories.com