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The second edition of High Power HF Filter Design is now available on Amazon. The book encompasses 468 pages, including over 525 equations, 400 figures, and 90 tables.

All of the material found in the first edition is included herein. Five new chapters and expansions of several original chapters add some 150 pages of additional design material.

This second edition is not only suitable for amateur radio operators needing filters for SO2R operation, but also professional design engineers. Several advanced filtering techniques and manipulation methods are outlined in this edition.

The writing and editing of the second edition is complete. This second edition is 50% larger than the first, boasting over 460 pages with more than 525 equations, 400 figures, and 90 tables. Publication is contingent on selection of a possible different publisher. The first edition is and will remain on Amazon.com, while a more technical publisher venue is being considered.

The first edition is adequate for likely most readers. The second edition has five more chapters and a considerably expanded treatment of the use of JK inverters. Additionally, the second edition covers a third filter design for 20m, isolation and shielding, advanced filter theory wherein select frequency zeros may be introduced into a filter’s stopband, and an expanded treatment of transmission line transformers, TLTs.

It is my hope that wherever the second edition is published, those people who purchased the first edition will be able to get the second edition at a considerable discount, in other words, no profit to me. The feasibility to offer this discount to first edition purchasers’ is under further review.

A ring rotator has been installed (October 2023) at 80 feet on the 90 foot tower. It is now home to a 4-element, 20m monobander enabling a second rotatable aperture on this band. The second tower’s location combined with the greater height affords improved transmission into the European countries compared to the C31XR.

High Power HF Filter Design is available through Amazon now. Soft cover is $42.95 and hard cover $49.95. The book is 289 pages in length with over 300 equations, approximately 275 figures and 66 tables. The first two-thirds of the book is for the advanced amateur while the final third is for a more mathematically, engineer-inclined reader. Those that are interested should review the Table of Contents on the ‘K0ZR Scribbles’ tab of this site or on the “What’s Inside” tab on the Amazon site.

A draft manuscript for my book High Power HF Filter Design has been submitted to Amazon Publishing. It is 294 pages in length with over 300 equations, 277 figures, and 66 tables. Designs, beginning to end, are discussed for 40m and 15m bandpass filters.

Work has already begun on the final chapter of High Power HF Filter Design. A 40m bandpass filter has been designed, built, and tuned up as the major subject of Chapter 9. A second filter for 15m is in progress and once it is built, its design documentation will be updated and the book “go to press”.

A project to capture how to design and build KW filters for HF was begun in December 2021 with completion anticipated around late 2022/early 2023. The application of the governing equations is included and the Appendix gets into the mathematical details of their derivation. Two chapters outline the design and construction of a 40m and 15m bandpass filter. A large amount of detail on capacitors and toroids is included with a great emphasis on the use of Norton transformations.

After almost 15 years of flawless service, I have replaced the Tentec Centurion with an ACOM 2000A automatic tuning amplifier. I have been reluctant to make this change given the great tenure of the Tentec, however the rapid band changing ability will be great to have. I struggled between the ACOM and another Elecraft KPA1500 which is one great amplifier. I elected to go with the ACOM primarily for its much quieter operation, opting not to have two amplifiers with fans running to keep their heat sinks cool.

Sadly, I decided to replace my Alpha 8410 in January 2021. While it was a 9.9 on a 10 point scale and effortlessly put out 1.5 KW or more on all bands, I decided that a) instant QSY was important to me, and b) the cost of replacement tubes “someday” was too high for my comfort. The replacement is an Elecraft KPA1500 and although its use spans a mere 24 hours, “I love it”. Great engineering, feature comforts, and excellent performance, especially when married up with an Elecraft transceiver.

Mid-November 2020 completed the addition of three Caribbean-oriented yagis on the 90 foot tower. Through the use of remotely controlled 1 x 2 transfer switches, RF is instantly channeled to these SE pointing antennas when needed; no antenna rotation required. The yagis cover 10, 15, and 20m. They worked flawlessly in CQWW CW 2020. A writeup is included in both Scribbles and Power Point Presentations sections.

Unfortunately, my Orion II has developed several problems; the master TCXO wants to wander outside its calibration range and there have been several instances where intermittent issues have shown up in the baseband processors. I am going to miss this radio that has served me well for 12 years.

The new K3S is just an updated version of the K3 which is already present. Some differences in VFO phase noise, less distorted audio, etc. are in the new K3S design.