Radio Habana Cuba: Dxers Unlimited Special mid-week edition for December 26, 2000
By Arnie Coro, radio amateur CO2KK
Hi, amigos, and welcome to a special edition of Dxers Unlimited, coming to you from Radio Havana Cuba... With the daily solar flux figures still at a nice and healthy above-180 mark, and also a nice and low value A index planetary geomagnetic disturbance indicator, it seems like we are certainly going to enjoy an excellent year's end period of HF propagation.
Today's special edition will be entirely devoted to Dxers Unlimited's "Radio Hobby Book of the Year" Award. YES, amigos, my friends, mes amis... Once again, our yearly BEST BOOK OF THE YEAR FOR RADIO HOBBYISTS will be reviewed here. The title of Dxers Unlimited's BEST RADIO HOBBY BOOK OF THE YEAR is BACKYARD ANTENNAS, written by world-known technical writer, and former editor of Radio Communications, Peter Dodd, G3LDO...
Of course, amigos, Peter is a very well-known amateur radio operator; his callsign again is Gulf Three Lima Delta Oscar, and this wonderful antenna book was published precisely this year 2000... For those of you who are familiar with the international ISBN system of book records, Backyard Antenna's ISBN number is 1 8272309 59 3 and there is even a WEB PAGE for this book that you can find at www.rsgb.org/books/extra/backyard.htm
Don't worry if you could not pick it up on this go around... I will repeat the WEB PAGE location for BACKYARD ANTENNAS, in my humble opinion one of the best books ever published dealing with practical amateur radio antenna systems and accessories. So, be ready to listen to a description of the contents of BACKYARD ANTENNAS by Peter Dodd G3LDO, the winner of Dxers Unlimited's BEST RADIO BOOK OF THE YEAR AWARD. Stay tuned; I'll be back with you in just a few seconds, this is Radio Havana Cuba...
You are listening to Dxers Unlimited's special edition, entirely devoted to a review of Backyard Antennas, a wonderful, easy-to-understand book providing a fantastic amount of practical information about antennas that can fit into what Peter, the author, describes as backyard locations, but that also apply to any other place where space for installing antennas is restricted... The book's Chapter One approach is to provide the reader with a clearly written introduction that contemplates even the legal aspects of amateur radio antenna installations that have to do with city planning authorities and other limiting factors like condominium rules and regulations. There is also a very nice introduction to HF propagation on page 9 that is really worth reading, especially by beginners. Chapter Two of Backyard Antennas describes in detail Center Fed Antennas for the HF bands and includes descriptions of resonant dipoles, vertical dipoles, the ground plane antenna and, as you might expect, a number of well-documented pages devoted to the all-important multi-band antennas that are required by anyone who has space for just one antenna. Chapter 2 of Backyard Antennas is one that you will want to read very thoroughly -- and not once, but two or three times...
Peter's direct, easy-to-understand text will then take you to Chapter 3, devoted to End-Fed and Marconi-type antennas, both for the HF amateur bands and the NEW LF bands... and that's a first, as I am almost sure that this is the first time that one of the WORLD's LEADING EXPERTS ON THE NEW LF 136 and 73 kiloHertz bands makes available practical data of antenna designs for these two new bands. Marconi antennas for LF, starting on page 39, is essential reading for anyone attempting to make use of the new LF, low-frequency ham bands, which are now available in many countries, and will soon be authorized by other nations, too... Then Peter takes you to CHAPTER FOUR, titled "Matching and Tuning," which runs through 25 pages of text and excellent illustrations. More about Chapter 4 of Backyard Antennas, and why I consider it one of the book's most important contributions to the amateur radio hobby, after this brief musical interval and station ID... Ricardo Queral is my sound engineer and producer, I am Arnie Coro, radio amateur CO2KK....
You are listening to Radio Havana Cuba, the name of the show is Dxers Unlimited, and this is the mid-week edition of the program that reaches you Tuesdays and Wednesdays UTC days, depending on your location... Today's special edition of Dxers Unlimited is entirely devoted to reviewing the Year 2000's Best Radio Book Award winner, Backyard Antennas, by Peter Dodd, radio amateur G3LDO, published by the Radio Society of Great Britain, which you can learn more about by visiting www.rsgb.org/books/extra/backyard.htm
Chapter 4 is titled "Matching and Tuning," and it spans from page 42 to page 67. In this chapter, all the most popular types of antenna-matching units are reviewed, and complete details are provided to build what yours truly considers to be the best-ever amateur radio antenna tuner designed. Peter describes it as a "BALANCED TUNER WITH PLUG-IN COILS," and the information provided, including circuit diagrams and several excellent photos, will guide you through the construction of this antenna tuner system that includes an antenna current sampling unit, to monitor the feeder current on each leg of a balanced transmission line... The tuner itself has INDEPENDENT TUNING for each leg of the balanced line, so you can actually achieve not only a good match and maximum power transfer between your transmitter and the antenna system, but also actually make the currents flowing on each leg of the balanced transmission line identical -- in other words, you will be able to operated a truly balanced system with all of its advantages. The balanced tuner with plug-in coils described in Chapter 4 of Backyard Antennas is power-limited -- in other words, with the components shown, it will work with powers that I estimate at a maximum of about 250 watts. BUT, if you do run high power, you can certainly follow the design ideas and use capacitors, coils and connectors capable of handling higher-power output transmitters.
Now, let's go to Chapter 5 of Backyard Antennas, one that I also found very interesting. Chapter 5 is titled "Loop and Slot Antennas for HF," a full 21 pages devoted to several different loops and one very special type of multi-band slot antenna that I had not seen before in any amateur or professional antenna book. The loops include small magnetic loops with lots of construction details, drawings and photos, so it is actually quite feasible to build them just by following Peter's well-written technical text... Chapter 5 is one you'll want to read several times if you are really short of space for installing HF antennnas, as the homebrew magnetic loops not only work well, but also cost a lot less than commercial ones.
Ever thought about homebrewing your own variable capacitors? Well, here is your chance to test your mechanical abilities, as G3LDO provides the complete plans for making air-spaced variable capacitors or appropriate spacings for the high voltages that are involved when using magnetic loop antennas....
This is Radio Havana Cuba, and you are listening to Dxers Unlimited's special edition, a complete description of Backyard Antennas, by G3LDO, the winner of Dxers Unlimited's Radio Book of Year 2000 award...
We are now going to take a look at Chapter 6 of Backyard Antennas, which spans from page 91 to page 107 and is completely devoted to small rotary beam antennas for HF, including Peter's DOUBLE D antenna, a very compact two-element beam that can be built at very low cost by anyone capable of working with hand tools. Peter also provides information on the now-famous MOXON RECTANGLE two-element compact beam, and he even includes a tri-band version of the MOXON RECTANGLE that will fit into the smallest backyard or rooftop that you can think of, and yet provide no less than 4 dB gain above a dipole, and -- what may prove to be more important to Dxers -- an excellent front-to-back ratio, when properly adjusted... Of course, you must follow Peter's detailed instructions on how to tune the MOXON RECTANGLE compact HF antennas for maximum front-to-back ratio, a condition that will make your reception of those elusive DX stations much better in the presence of powerful signals coming from the back of the beam. I built a scale model of this antenna for 2 meters and was amazed at the almost 30 dB front-to-back ratio achieved -- yes, 30 dB front-to-back ratio, actually very near to that figure is possible when carefully adjusting a MOXON RECTANGLE two-element antenna.
Chapter 7 is devoted to VHF and UHF antennas, and includes both omnidirectional and beam antennas... Following Peter's excellent logical presentation of topics, the chapter gives you a lot of background information and includes several low-cost antennas that can be built using readily available materials. Two of them, a 3-element Yagi and a 2-element Cubical QUAD for the 2 meter band, are projects that can be completed during a few hours of your spare time, and will provide excellent service at your amateur radio station, both for fixed and portable use.
Chapter 8 of Backyard Antennas is devoted to the all-important topics of antenna materials, construction and support systems, including WIND LOADING, an often-neglected factor that has brought more than one amateur antenna installation crashing down during heavy winds...
Chapter 9 is, in my opinion, one that you should read with a notebook ready to write some very important things that Peter explains in such a clear way that it has already helped many to understand such complex topics as Balanced to Unbalanced transformers, or BALUNS, when they read Pages 161 to 174... Although there is an excellent book devoted to this topic by another author, these thirteen pages will give you an excellent background about baluns, and again with the excellent illustrations and photos, you can start experimenting and making your own balanced to unbalanced transformers to match a wide range of impedances... The book's final chapter, number 10, is titled "Estimating and Measuring Antenna Performance" and it is also really worth every single minute devoted to reading it. Then at the end of this wonderful, well-written, fully documented antenna book, there is a glossary of antenna terms and a five-page Appendix that provides a lot of valuable information.
NO WONDER BACKYARD ANTENNAS, by Peter Dodd G3LDO, won -- without any doubts -- Dxers Unlimited's BEST RADIO HOBBY BOOK OF THE YEAR AWARD. Congratulations, amigo Peter Dodd, G3LDO for this wonderful contribution to the development of the amateur radio hobby! And here is Arnie Coro's advice to you all: Try to get your copy as soon as possible; you will enjoy reading it a lot, and you will certainly have a nice time building some of the excellent antenna designs that G3LDO provides in his outstanding book.
And now, amigos, as always at the end of the show, here is Arnie Coro's Dxers Unlimited's HF propagation update and forecast: Solar flux is hovering very near 190 units... the A index is at a nice and low 07... and the latest K index I monitored here at CO2KK was also a nice and low 1. Six-meter band propagation was a reality Tuesday morning from Venezuela and Aruba to Europe... Yes, a brief opening around 13 hours UTC, and we may see more of the same Wednesday morning too... So far this year's northern hemisphere winter solstice Sporadic E season has proven to be the worst of them all in many, many years, so it might be a good idea to tell ionospheric researchers about this fact, to see if they come up with a possible answer. For short wave listeners, the best nighttime reception will be from 6 megaHertz all the way up to 16 megaHertz... First hop skip will be better between 6 and 10 megaHertz during your local evenings, while double hop F propagation will provide long range DX on the 41, 31, 25 and 22 meters international shortwave broadcast bands.
See you next Saturday and Sunday UTC days at the weekend edition of Dxers Unlimited, amigos, and if you are already an amateur radio operator, go to ten meters, tune your radio right on 28.5 -- 28500 kiloHertz -- and let's have a nice year's end QSO there!!!
prepared 12-26-2000; transmitted 12-28-2000
delayed in transmission due to heavy weatherArnie Coro CO2KK
Havana, Cuba
December 26, 2000Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba, Havana, CUBA
e-mail: arnie@radiohc.org
To Arnie Coro's Dxers Unlimited
Back to NY Transfer's RHC main page