Antennas By N6LF

Antennas

Antennas are a rich field for investigation and innovation, even after more than a hundred years.  Since I was first licensed over 65 years ago antennas have been my passion and over the years I've published articles on antennas and notes.  Amateurs rarely design and build their own equipment these days but antennas are very often home brewed and provide a means for improving station performance at modest cost.  60 years ago Tom Erdmann, W7DND(SK), told me that if I had $100, I should spend the first $90 on the antenna, the next $9 for the receiver and the final $1 on the transmitter. Of course prices have gone up bit but those proportions are still sound advice. I can honestly say I have a lot more time and effort  invested in my antennas than in  station equipment.  This web site provides access to my articles and notes. The work reported here is a mix of analytic (calculations), NEC modeling and field experiments on actual antennas. Each of these has it's place but the best picture emerges when all three techniques are combined.

Please note, I try to close each post to comments. Once in a while I forget to push the right button and a post may be open. However, I assume I'm perfect and always have the posts closed, so I don't look for comments.

Switchmode converter book

Many years a go Ed Bloom and I wrote a book on switchmode converter circuits.  I have a .pdf of it for anyone interested: Download Modern DC-to-DC Switchmode Power Converter Circuits

Loop RX antennas

Multi-turn loop antennas are popular LF-MF receiving antennas and while there is lots of info on them I've recently turned up a really neat technical paper on "Coil Antennas", circa 1919 which may be of some interest.  Download Coil Antennas 1919

Valley Radio Club talk 7 Feb 2020

Here is the file for the talk I gave last night.  73

Download 2200 and 630m Presentation -4

 

LFMF notes

Here are some notes on LFMF tuning inductors which may be of interest:

Download Optimum Inductor l-D ratios

Download Optimum Q LFMF loading inductors

Download Wet Inductor Tests

630/2200m TX antenna

Download 630-2200m N6LF TX antenna

I've rebuilt my 630m TX antenna and retuned it to 2200m.  630m tuning will be added in due course.  Here is a description of the latest LF/MF TX antenna at N6LF

A note on floating short circuited loops for inductor tuning.

In older equipment (circa WWII) we occasionally see a short circuited loop or small disc inside a coil to adjust the inductance.  This certainly works but has a bad effect on coil Q.  Attached is a very short note on a experimental test of this type of inductance adjustment.  Download Chapter 6 tuning loop note

Snubbers for Electronic Circuits

Some years ago I wrote a book on snubber circuits for power electronics.  Strictly speaking this is not a hot topic for amateurs but I thought it might help a few so here it is: Download Snubber e-book complete .  For those who don't need to know how to build the watch here's a much shorter summary: Download CD snubber design .

I have also had requests for copies of some of my old technical papers, applications notes, etc.  As I scan them I'll add them to this post.  Recently I was asked for Intersil applications note AO35: Download Intersil AO35

New 630 transmitting antenna a WD2XSH/20

I have recently rebuilt my 630m antenna to use a counterpoise in place of the radial system of 128 wires lying on the ground.  I wanted to see if a much simple counterpoise system would provide comparable efficiency.  Take a look at: Download N6LF Transmit Antenna July 2017

630m-2200m talk

I gave a short talk last night to some local hams on our new 630m and 2200m bands.  Here is PowerPoint file for that talk: Download 2200 and 630m Presentation -2   that's a .ppt file.  For new software using the .pptx format: Download 2200 and 630m Presentation -2 . 

LF-MF antenna notes

 

The present draft of these notes, while far from perfect, may be helpful to many amateurs.  For that reason I've posted them in their present form with the understanding they will be revised, probably several times, in the coming years. 

By all means let me know if I've forgotten something useful and, even more importantly, if I've made a mistake!  A lot of other peoples work has been included 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 Chapter 6  tuning inductor design