Handiham World Weekly E-Letter for the week of Wednesday, 30 August 2017


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Courage Kenny Rehabilitation Institute Handiham World Weekly E-Letter for the week of Wednesday, 30 August 2017

This is a free weekly news & information update from the Courage Kenny Handiham Program, serving people with disabilities in Amateur Radio since 1967. 

Our contact information is at the end.

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Welcome to Handiham World.

In this edition: 

  • A note from the coordinator

  • Helping people who are blind see the solar eclipse

  • Hearing the stars

  • Things Technical Part 4—Why Radials?

  • Down memory lane…

  • Check into our nets!

  • ...And more!


A note from the coordinator...

The Handiham Program office is getting busy! Maybe it’s because it’s the end of August, and people are getting out of summer vacation mode and into fall work mode. Maybe it’s because more people are being bit by the “upgrade” bug. In any case, it is a good problem to have!

Last weekend, we sent out a survey to gage interest in having Radio Camp in 2018. Please be sure to share your thoughts if you have not already done so. You can find the link at https://www.surveymonkey.com/r/92Y8B5S

The Handiham Program also acquired a new mic to use for recording the podcasts. All attempts to record last week with the available equipment were a dismal failure. This week’s podcast should be a success!

In the newsletter this week, I have included some articles about making the solar eclipse accessible for persons who are blind or vision impaired as well as a TED talk about a blind astronomer who is making accessibility her priority, we will continue with the final installment of our series on radials, and there is another story from a past issue of Handiham World.

Do you have a story to share about your ham radio related activities? Please send your articles and stories via email to Lucinda.Moody@allina.com or by calling me at 612-775-2290.


Helping the Blind See the Solar Eclipse

While the solar eclipse took place over the United States last week, the impact of the project to help people who are blind experience the occasion will continue to be felt as new methods are developed to help all people have the ability to experience events previously believed to be limited to those with sight. Check out the following story to learn more. https://www.pri.org/stories/2017-08-11/helping-blind-see-solar-eclipse


Hearing the Stars

Here is a TED talk about a blind astronomer who found a way to hear the stars. https://www.ted.com/talks/wanda_diaz_merced_how_a_blind_astronomer_found...


Things Technical Part 4—Why Radials?

From the Spring 1993 issue of Handiham World, editor Pat Tice, WA0TDA, shares the following introduction…

In this final installment of his radial series, associate member Don Newcomb, W0DN, makes the case for radials and debunks phony ad claims. Thanks, Don…Now I’m going outside to dig up my back yard and plant some wire!

Reprinted with permission from DX Engineering / Butternut

So far, we’ve been talking about vertical antennas operating with and without radial systems at ground level. Can’t we simply raise the antenna a few feet above ground and forget about radials and losses as some of the ads suggest? Not really, unless we’re willing to forget about efficiency too, and, in the case of most base-fed verticals, we’ll probably need resonant radials to get low SWR if we raise the antenna more than about 10 feet above ground level. A physical ¼-wave radiator, recall, can operate in a resonant condition because the earth, even lossy earth, provides a “mirror image” of the “missing” half of a ½-wave dipole. The lower end of such an antenna is at a low-voltage/high-current point and has a feedpoint impedance of about half that of a dipole, or 35 ohms plus ground loss resistance, and, if the feedpoint is quite close to the earth, such an antenna will also be resonant. If, however, the antenna is elevated more than a foot or so, the length of any vertical lead to the ground connection will become part of the vertical radiator and the antenna will no longer be resonant on one or more bands. For the same reason, an elaborate radial system at ground level will do little or nothing for a vertical antenna atop a tall tower. Any radial or other ground system should enter the picture right at the antenna feedpoint of a base-fed antenna.

We know that it takes about 100 radials at ground level to overcome all our ground losses (bearing in mind that very few amateurs have either the real estate or the ambition required for 100 radials) and that four quarter-wavelength radials will provide about the same efficiency at antenna base heights of a half-wavelength or so. As the height above ground decreases, the number of radials required for the same efficiency naturally increases. So at heights of a quarter-wavelength, a dozen or more resonant radials might still be required for an essentially lossless ground system. Then there’s another problem to solve: that of finding a tower or mast to support the antenna (how much are you willing to spend to accomplish what?)

Apart from reducing the number of radials needed for reducing the ground loss resistance to some minimum level, is there really any great advantage to mounting a vertical on a tall tower or mast? Maybe, maybe not. If the antenna is in a dense forest full of leafy trees that can soak up vertically polarized RF energy or in an urban canyon of apartment buildings, it makes sense to elevate a vertical in order to be clear of local obstructions, particularly on the higher-frequency bands. If, on the other hand, the antenna is in the clear at ground level—and if you have the room for radials—it’s unlikely that the cost of a tall tower could be justified. The vertical angle radiation pattern of a vertical at ground level is essentially the same as that of the same antenna fifty feet above ground where initial adjustment will be more tedious and hazardous. The main difference between above-ground and ground level vertical installations if both are in the clear is that more radials will be needed at ground level to overcome the earth loss resistance.

But what about the no-radial designs with or without a remote matching device at the lower end? One ad asks us to believe that a 17-ft. radiator is a “halfwave” or at least plays like one on 20 meters, although a half wavelength on 20 meters is closer to 33 feet. Still, 17 feet is tall enough for relatively high radiation resistance on 20 meters, and the loading from the traps for the higher frequency bands probably doesn’t introduce too much loss resistance. But how well would this antenna play on that band at ground level or even a few feet off the ground? Probably no better or worse than our plain-vanilla quarter wave radiator because the ground loss resistance will still be there waiting to gobble up most of your power. “No ground radials” perhaps sounds alluring, but until we can make claims for “no ground LOSSES,” the world will remain a dangerous place for RF from vertical antennas operating in the HF range! “Ground radials,” one must assume, are lengths of wire that are to be buried in the earth or draped on the surface. Why these would be more annoying than, say, “counterpoise radials,” the kind that are NOT to be buried, is a bit unclear. One “no ground radial” antenna seems to employ a “counterpoise” system of greatly shortened radials (so it uses radials after all!), though perhaps not as the ad-writer imagined.

At this point, we should probably make a detour for a few definitions in order to make better sense of what follows. For years, the terms “ground radials,” “ground plane,” and “counterpoise” have been used almost interchangeably until their separate meanings have been all but lost.

The ARRL Antenna Book (15th edition) offers the following definitions:

Ground plane—a system of conductors placed beneath an elevated antenna to serve as an earth ground. Also see counterpoise.

Counterpoise—A wire or group of wires mounted close to the ground, but insulated from ground, to form a lower-impedance, high capacitance path to ground. Used at MF and HF to provide an RF ground for an antenna. Also see ground plane.

A counterpoise, then, depends on a fair amount of capacitance to ground for proper operation, and that means (a) that the counterpoise must be near the earth in terms of wavelength and (b) that the counterpoise must cover enough surface area to develop the necessary capacitance between it and the earth below. If you view the counterpoise as one plate of a capacitor and the earth as the other, it’s obvious that the capacitance between the two will diminish as the separation between them increases.

Counterpoises are most often used with vertical antennas for the lower-frequency bands when buried radials are out of the question, and the conductors that make it up often take the form of a spider web for the sake of increased capacitance. They’re seldom placed any higher above earth than is necessary to permit unimpeded foot traffic, about seven feet or so. At much greater heights where capacitance to earth is not a consideration, elevated ¼-wave radials will suffice. And don’t overlook the possibility that a set of resonant radials for one band may also provide an effective counterpoise system on one or more lower-frequency bands. Four ¼-wave radials for 40 meters, for example, should provide enough capacitive coupling to earth to function as a capacitive counterpoise on 80/75 and 160 meters when antenna base heights don’t exceed about 25 feet. This height represents less than 1/10 wavelength on 160 meters and twice that on 75/80 meters, and it is within this approximate range that counterpoises can be expected to work without becoming much larger. Keep this point in mind as we resume our discussion of the “no radial” vertical antenna.

It should be apparent that most mobile antennas operate according to the counterpoise principle, the metal body of the vehicle providing the capacitive coupling to the earth itself.

In the case of our “no radial” antenna that uses an abbreviated “counterpoise radial” system, we might well wonder what its precise function is. Near the ground the short radials won’t do much to reduce the ground loss resistance—certainly no more than the same number of ordinary wire radials of the same or greater length—and at even greater heights it’s not at all clear how the vestigial radial system will take the place of the dozen-odd 1/4-wave radials we’d need for a real dent in the ground loss resistance once the antenna is raised to a ¼-wavelength or so above the earth on 20 meters. The remote tuning/matching device takes the place of resonant radials as far as overall resonance and SWR are concerned, but will do nothing about ground losses. Elevated radials are usually ¼-wavelength because it’s a convenient resonant length, but even longer radials would be desirable if they didn’t make the overall antenna system reactive. The function of a “ground plane” radial system (see above definition) is the same as that of “ground radials” or “counterpoise radials”: to provide low-loss “return” paths for currents that might otherwise prefer to flow on or along the lossy earth. Once again, “the more wire the better” is a safe principle to follow. The makers of the “no radial” antenna have recently introduced a slightly taller 7-band version that claims “electrical half-wave length” operation, although its physical height falls well short of that required for even a quarter wavelength on 40 meters. How well this “no radial” vertical may be expected to play under competitive conditions on 40 meters, where the short “counterpoise radials” will be even less effective in reducing ground losses at any height than they are on 20 meters, is probably a fair question that deserves an answer, particularly since the manufacturer insists on this antenna’s “independence of ground.” That’s going a bit too far, perhaps, because its performance will depend on the same factors that affect more conventional vertical antennas that use messy, unsightly, inconvenient, and totally inexpensive “ground’ radials to deal with ground losses. Independent of ground in that the remote tuner/matcher provides low SWR? Okay, no quarrel with that. But low SWR by itself tells us next to nothing about how well the antenna is performing. Independent of ground as far as efficiency is concerned? NO WAY!

Suffice it to say that any vertical that will play close to the earth with no radials at all will play MUCH better over a good radial or counterpoise system. And whether a particular system is a good one depends largely on how much surface area it covers and how many wires are used to cover it. A simple “no-radial” multiband vertical may be easily constructed for next to nothing if one already has an “antenna tuner” and a handy tree limb. If the vertical wire is made about 25 feet long, its performance should be roughly equivalent to that of any commercially available “no-radial” vertical antenna of the same general length (height) on 40 through 10 meters and occupying the same space, the longer wire lengths tending to favor the lower bands and the shorter lengths the higher bands. SWR at the feedpoint may reach 20:1 or more, but “ladder-line” has very low loss to begin with, so the additional losses because of very high SWR are unimportant. The difference in performance between this simple vertical wire and the commercial “no-radial” vertical will not be worth examining in the average case, and either can be made to outperform the other by laying out a GOOD radial or counterpoise system at the antenna’s feedpoint, especially when the antenna is near the earth. Earth losses are the major limiting factor to vertical antenna performance, and no remote tuner or matcher can do anything about that.

Obviously, there are a number of trade-offs involved in every antenna installation, and there is no single antenna type or particular installation that will be ideal for everyone on every band. Before you blow your lunch money for the next six months, you should probably become familiar with the most basic types and understand their characteristics. If you have an ARRL Antenna Book, read it. Most of the answers to your questions are there, though you have to dig a little to find them. It’s well worth it.

If you retain nothing from the foregoing discussion but a vague awareness that radials are somehow FUNDAMENTAL to the successful operation of vertical antennas, you’ve grasped the main point. Even those vertical antennas that supposedly don’t need radials will always operate more efficiently over a good radial system than over no radials at all. Radials may or may not affect the SWR of elevated or ground-level verticals, but that’s incidental to their primary function, which is to reduce the ground losses that might otherwise keep the vertical from operating more efficiently.


Down memory lane...

In honor of the celebration of 50 years of the Handiham Program, here is a story from Georgia about Josh Lambert, first printed in the Spring 1991 issue of Handiham World.

Ham Radio Satisfies Search for Knowledge, Friendships

At Shamrock Junior High School in Decatur, Georgia, Josh Lambert is just like any other junior high student. He is a member of the school’s cross country, track, and wrestling teams, and is a representative on the Human Relations Committee. He is a good student and very outgoing. Outside the classroom, his passions are fishing, reading, computers, and ham radio. Pretty regular things for a 13-year-old, except for the fact that Josh is blind.

Josh’s interest in ham radio began when he was 7, after his parents bought him an all-band radio at a garage sale. Josh was now able to listen to the conversations of pilots from a nearby airport as well as ham conversations and Morse code. This whet his appetite for more. Then his sister surprised him with an antique Philmore practice code key. Josh taught himself code, and, the more he learned, the more he was determined to become a ham radio operator.

When the Lamberts moved to Georgia, Josh met Fred Dorsey, and his dream became a reality. Fred, a former pilot with Eastern Airlines, “is a driving force behind Josh’s successes,” said Josh’s mom, Arlene. “Fred has donated countless hours, equipment, and encouragement to Josh to continue to ‘go for it’,” said Arlene. With Fred’s encouragement and Josh’s determination, Josh was able to work his way from novice to general license in less than a year!

In addition to his school activities and hobbies, Josh was honored by being selected to the Atlanta Dream Team, an organization made up of specially-talented students in Georgia whose main purpose was to help bring the Olympics to Atlanta. Josh replied to an advertisement along with 2,500 other students and was eventually one of 60 chosen to go to Tokyo to convince the International Olympic Committee that Atlanta was the best site for the 1996 Summer Olympics. The Dream Team must have had an effect since Atlanta will host the Olympics in 1996. As a member of the Dream Team, Josh will be able to participate in the Games.

His involvement in the Dream Team has a unique sidebar story. After his return from Tokyo, Josh was talking with a ZL8, Zack, who turned out to be the pilot on the airplane that had taken Josh and his fellow Dream Team members to Tokyo! Josh was also able to talk with WZ4SIR, Ron, from the space shuttle Columbia on 2 meters in November.

Josh has met so many bright, stimulating, and creative people through ham radio,” said Arlene. “His travels have been worldwide and his knowledge broadened through his contacts with fellow hams. Ham radio has fulfilled a young man’s search for knowledge, friendship, and new challenges.”


What are you waiting for? Check into our Handiham nets... Everyone is welcome! 

How to find the Handiham Net: 

  • The Handiham EchoLink conference is 494492.  Connect via your iPhone, Android phone, PC, or on a connected simplex node or repeater system in your area.

  • The Handiham Net will be on the air daily. If there is no net control station on any scheduled net day, we will have a roundtable on the air get-together.  

    Cartoon multicolored stickman family holding hands, one wheelchair user among them.

Our daily Echolink net continues to operate for anyone and everyone who wishes to participate at 11:00 hours CDT (Noon Eastern and 09:00 Pacific), as well as Wednesday evenings at 19:00 hours CDT (7 PM).  If you calculate GMT, the time difference is that GMT is five hours ahead of Minnesota time during the summer.

Doug, N6NFF, poses a trivia question in the first half of the Wednesday evening session, so check in early if you want to take a guess.   The answer to the trivia question is generally given shortly after the half-hour mark.  A big THANK YOU to all of our net control stations and to our Handiham Club Net Manager, James, KD0AES.


Membership

  • You can pay your Handiham dues and certain other program fees on line. Simply follow the link to our secure payment site, then enter your information and submit the payment.  It's easy and secure!

    • Handiham annual membership dues are $12.00.  The lifetime membership rate is $120.00.
      MEMBERSHIP DUES PAYMENT LINK

    • If you want to donate to the Handiham Program, please use our donation website.  The instructions are at the following link:
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How to contact us

There are several ways to contact us.

Postal Mail:

Courage Kenny Handiham Program
3915 Golden Valley Road MR#78446
Golden Valley, MN 55422


E-Mail:
Nancy.Meydell@allina.com


Preferred telephone: 1-612-775-2291
Toll-Free telephone: 1-866-HANDIHAM (1-866-426-3442)


Note: Mondays through Thursdays between 9:00 AM and 2:00 PM United States Central Time are the best times to contact us.


You may also call Handiham Program Coordinator Lucinda Moody, AB8WF, at: 612-775-2290.

73, and I hope to hear you on the air soon! 

For Handiham World, this is Lucinda Moody, AB8WF

The weekly e-letter is a compilation of software tips, operating information, and Handiham news. It is published on Wednesdays, and is available to everyone free of charge. Please email Nancy.Meydell@allina.com  for changes of address, unsubscribes, etc. Include your old email address and your new address.

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