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Showing posts from May, 2012

Simple Antennas for the Amateur Radio Operator--a continuing series

What kind of antenna will you be using during the ARRL Field Day (23-24 June 2012)?

If you will celebrate the event by going to a club site on that Saturday and Sunday, you may be using anything from a tribander on a portable tower to phased verticals and everything in between.  One of the enjoyable aspects of Field Day is using antennas that you may never be able to afford or build.  Also, your club may be using state of the art transceivers, solar power, or even wind- generated power for this communications exercise.  One never knows what operating system will present itself when you take your place facing a new rig or a new logging system.  That is part of the thrill associated with Field Day.

I will be lucky this year.  The normal 2-day summer drag race set for that day has been shortened to one day, which means my tower announcing duties will be brief.  I will still have time to meet members of the Big Island Amateur Radio Club that Saturday night at Hilo's Wailoa Visitors Cent…

Simple Antennas for the Amateur Radio Operator--a continuing series

Happy Memorial Day to veterans and their families!  From one veteran to another, thanks for your service to our country and for covering my back during those dangerous times in Southeast Asia many years ago.  Also, thank you to the amateur radio operators who relayed thousands of health and welfare messages for our forces overseas.  Many amateur radio operators are continuing their service through MARS, public safety communications, and emergency agencies such as the Red Cross, SATERN, and civil defense. 'Makes me proud to be an amateur radio operator.

With the ending of the school term last week, my xyl and I have some free time to pursue until the fall semester begins.  For me that means house repairs, the usual routine of daily errands, and, of course, spending some time launching rf into the ionosphere.  Among my projects this summer is a thorough cleaning of the venerable Swan 100-MX, which has served me faithfully since 1983 and a continuing effort to bring an old Kenwood TS-…

Simple Antennas for the Amateur Radio Operator--a continuing series

ANOTHER SIMPLE ANTENNA PROJECT

How would you like to make a simple, portable antenna that you can use on vacation or in your home?  Such an antenna would be useful for those in restricted operating environments.  I ran across an article by Craig La Barge, WB3GCK, while I was researching limited space antennas.  As you know, my antenna farm is confined to a small backyard, and limited space antennas are what I'm accustomed to using.  Anyway, the article called "The Up and Outter Antenna" gave me a few ideas for stringing up yet another skyhook to warm the ether.

La Barge used approximately 30-feet of light gauge wire attached to a long pvc pole with another 30-foot piece of wire running through his vacation home on the Outter Banks of North Carolina.  That wire served as a counterpoise for the vertical element.  He fed the antenna system with open wire to minimize losses.  La Barge said the design may go back as far as the 1920's or 1930's.  He cited work by famed …

Simple Antennas for the Amateur Radio Operator--a continuing series

What do you do if you can't erect an outside antenna?  You could just give up and let the CC&Rs,  HOAs, and space restrictions win.  But that's not what creative amateur radio operators do to stay on the air.  I ran across this problem a few days ago when one of my younger amateur radio friends said he couldn't put up an outside antenna because of the restrictions of his area.  He lives in a crowded subdivision with neighbors all around.  Besides the restrictions imposed by his CC&Rs, space around his home is very limited.  So, without getting into the sticky area of tenant leases, housing committees, and noisy neighbors, I offered to do what I could to get him back on the air.  Fortunately, my friend can operate mobile and portable from parks and other public areas.  At first I suggested that he continue that type of operation until I could find a few hints for indoor antennas.

While I'm not a strong advocate for indoor antennas, such antennas, if properly desi…

Simple Antennas for Amateur Radio Operators--a continuing series

The ARRL's annual Field Day communications exercise is coming 23 June 2012.  Field Day is one of the largest operating events in the United States and Canada.  Whether you operate from a multi-station position or run emergency power from your home, Field Day will test your creativity, endurance, and ability to withstand the forces of nature for at least one day.

Since I'm commited to announcer duties for that weekend at the Hilo Drag Strip, my participation will be limited.  I plan to run class 1-C mobile from the Drag Strip using my emergency kit stashed in the Odyssey van.  While I camp overnight at the race track, I will set up the Yaesu FT-7, a few hamsticks on a mag mount with several radials, and a deep cycle marine service battery for several hours during the event.  This should be a good test under field conditions.

If the first day of racing finishes early, I most likely will meet members of the Big Island Amateur Radio Club at Hilo's Wailoa Community Center for its…

Simple Antennas for the Amateur Radio Operator

A few days ago, the good folks at eham.net ran a series of comments from amateur radio operators who used the MFJ 1622 portable antenna system.  The antenna consists of a tapped air coil, a 5 1/2 foot antenna, a counterpoise wire, a short length of coax, and a sturdy clamp to attach the antenna to a bench, railing, or other support.  I was gratified to see some positive reports on this compromise antenna, which, despite its faults, can get you on the air in a space-restricted environment.  The MFJ 1622 is a copy of an older design by B & K, which marketed the device in the 1970-1985 time frame.  I bought one of these when I was first licensed as a novice, used it with some success, and later stored it for emergency use.

Presently, my B & K system is located in my van, along with some coax, a spare ATU, about 100-feet of wire, a deep-cycle marine battery, and some pre-cut counterpoise wire.  My trusty Yaesu FT-7 serves as the rig.  Despite the 10 to 20 watts output of the old Y…

Simple Antennas for the Amateur Radio Operator--a continuing series

This has been a very busy day.  My xyl and I were asked to help with the annual May Day Celebration today at Laupahoehoe High School.  The students put on quite a show with Hawaiian Hula, chants, stories, and local music.  In the course of the day's events, several students asked about the antenna on the roof of my Odyssey van.  After I told them the antenna wasn't for CB, but rather for amateur radio, they seemed more interested in seeing what my modest rig would do.  So, I selected a frequency for one of the FM repeaters on the island of Maui and had a good time introducing some students to my fellow hams.  I also showed them my emergency HF setup behind the final row of seats.  I didn't have the HF antenna mounted, so I just let them look at the equipment (Yaesu FT-7), the huge deep cycle marine battery, the hamsticks near the sliding door, and the mag mount nestled under the last row of seats.  Too bad I wasn't better prepared for a show, but the VHF demonstration …

Simple Antennas for Amateur Radio Operators--a continuing series

THE FEEDING AND CARE OF THE INVERTED "V" ANTENNA

In my last post, I described a simple inverted vee that could be built and erected by one person at a modest cost.  In my case, I had enough wire and and pvc mast sections to build this 40-10 meter antenna without going to the nearest hardware store.  Fortunately, I also had a hundred or so feet of 450-ohm twinlead, a spare 4:1 balun, and a good ATU (Drake MN-4) to finish the job.  With each leg of the "v" 33-feet long, you have an antenna that can work from 40 to 10 meters.  If you want to explore 80 meters, make both legs of the "v" 65-feet long.  These measurements are approximate--you may have to trim each leg a few inches to make a better match.

If you don't have twin lead, you can also use approximately 40 to 50 feet of coax to feed the antenna.  Of course, the coax will feel happiest on one band and its third harmonic.  That characteristic makes it possible to use a 40-meter inverted "v" …