Antennas By N6LF

Antenna design ideas for radio amateurs by Rudy Severns 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.

October 17, 2006 in Introductory comments | Permalink | Comments (0)

Loop on the ground RX antennas

I'm continuously seeking a better LFMF receiving antennas.  I've tried many different kinds but had not tried a simple loop lying on the ground, a LOG.  I had been very skeptical of these but tried one anyway.  The result, at least for me at my QTH, was very successful.  Here is a note showing the details along with WSPR comparisons between antennas over different paths: Download 630m LOG notes.  I'm not suggesting this is an antenna for everyone but as shown in the note it works great for me.

November 03, 2022 | Permalink | Comments (0)

Multi-turn loop receiving antennas for LFMF

For the next edition of the ARRL Antenna Book (the 25th) I've written a section on Multi-Turn Loop Antennas for LFMF reception.  It will be many months before this published and available from the ARRL.  I felt the topic might be of more immediate interest to the LFMF gang and have permission to post a copy of the draft: Download Chap 22 LFMF RX loops .

The ARRL note mentions direct experimental measurements of self resonant frequency.  Here is a note with more detail on the measurements and modeling comparisons between different versions of NEC:  Download Loop excerpt 2

December 17, 2021 in 630m antennas, ARRL antenna articles, Receiving antennas | Permalink | Comments (0)

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

November 18, 2020 in Books | Permalink | Comments (0)

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

May 05, 2020 in receiving antennas, Receiving antennas | Permalink | Comments (0)

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

 

February 08, 2020 in ARRL antenna articles | Permalink | Comments (0)

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

January 28, 2020 in 630m antennas | Permalink | Comments (0)

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

October 08, 2019 in 630m antennas | Permalink | Comments (0)

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

May 08, 2018 in 600m experiment | Permalink | Comments (0)

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

December 11, 2017 in MOSFET's | Permalink | Comments (0)

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

July 15, 2017 in 600m experiment , 630m antennas | Permalink | Comments (0)

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Recent Posts

  • Loop on the ground RX antennas
  • Multi-turn loop receiving antennas for LFMF
  • Switchmode converter book
  • Loop RX antennas
  • Valley Radio Club talk 7 Feb 2020
  • LFMF notes
  • 630/2200m TX antenna
  • A note on floating short circuited loops for inductor tuning.
  • Snubbers for Electronic Circuits
  • New 630 transmitting antenna a WD2XSH/20

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