Antennas By N6LF

LF-MF antenna notes

For many months I've been working on a set of design notes LF-MF antennas intended for hams.  These notes still have a very long way to go but there has been sufficient progress that the present draft of the notes may be helpful to many amateurs.  For that reason I've decided to post the notes in their present form with the understanding that these notes will be revised, probably several times, over the coming year(s).  The portion of the notes I've posted are mostly practical examples with a minimum of math.  This will be satisfactory for most users, however, some of you are more sophisticated with technical backgrounds who would like to see the BEEF, i.e. where does all this stuff come from?  I'm in the process of creating a series of appendixes which contain all the math and detailed explanations of things like proximity and skin effects, self-resonance in inductors, soil electrical characteristics, etc.  These are  referenced in the  posted text but for the most part all you see at this time is "Appendix TBD".  The appendixes will be added over the coming year as I get time to clean them up and upload.

By all means let me know if I've forgotten something useful and even more importantly, if I've made a mistake!  There is a lot of other peoples work here but the mistakes are all mine!

GL and 73, Rudy N6LF, WD2XSH/20

LF-MF notes: 

Download Preface-Table of contents

Download Chapter 1  LF-MF overview

Download Chapter 2  Simple verticals w/o top-loading

Download Chapter 3   Top-loaded verticals

Download Chapter 4   Inductive loading and multiple tuning

Download Chapter 5  Ground systems

Download Appendix 1

Download Appendix 2

630m Antenna Support Poles at N6LF

I have recently moved to a new QTH with several acres of clear farmland but no trees for antenna supports.  So I had to come up with a means to support a large 630m umbrella vertical and other experiments with wire antennas.  Here's what I did: Download Saginaw antenna support poles . 

A large ID clamp-on RF current transformer

Earlier this year I posted a description of a simple clamp-on RF current transformer.  Since that time I have updated the design with a much larger ID and the core held in a spring-clamp that allows easy on/off in the field.  The following is an update of the earlier post: Download Current transformer 2 .  File size = 460 kB.

Tower resonance measurements

I mentioned on the towertalk reflector that I had been trying to make accurate measurements of resonance in grounded towers with large antennas systems on them.  A number of people asked for the details.  So here they are: Download Some notes on measuring tower resonances .  These are only preliminary notes which give the general idea of what I'm about.  In due course they will be updated.

73, Rudy N6LF