Antennas By N6LF

Time 2021-01-09 13:04:41

Web Name: Antennas By N6LF

WebSite: http://rudys.typepad.com

ID:161591

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Antennas,By,N6LF,

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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. 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 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 Download 630-2200m N6LF TX antennaI 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 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 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 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 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 . 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/20LF-MF notes: Download Preface-Table of contents Download Chapter 1 LF-MF overviewDownload Chapter 2 Simple verticals w/o top-loadingDownload Chapter 3 Top-loaded verticals Download Chapter 4 Inductive loading and multiple tuning Download Chapter 5 Ground systems Download Chapter 6 tuning inductor design

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Antenna design ideas for radio amateurs by Rudy Severns N6LF

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