Sunday, May 20, 2012

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 DXer C.F. Rockey, W9SCH, who named the antenna "the upper and outter" to define its main elements.  La Barge also reference an article by Lew McCoy, W1ICP (SK), who published plans for "the limited space antenna" in the October 1960 issue of QST.  The late L.B. Cebik, W4RNL, published an article describing a coax version for 10 meters.  According to McCoy, the antenna covered 80 to 10 meters using open wire feed line.

Using La Barge's and McCoy's ideas, I quickly made my own copy for my backyard antenna farm.  I used an old 33-foot MFJ fiberglass pole I had in the garage for supporting the vertical element and 33-feet of #22 gauge hookup wire for the horizontal element.  The horizontal counterpoise was supported by  three wooden posts approximately 3-feet off the ground.  The horizontal wire ran through my garden, so it didn't present a danger to neighbors.  Like my other vertical antenna projects, the fiberglass support could be lowered on a swivel to keep visual impact low and offer some protection from lightning.

HOW DOES IT PERFORM?

This homebrew version of the La Barge/McCoy "upper and outter antenna" does fairly well, getting as many contacts as I normally get on the inverted vee on the other side of the garden.  The "upper and outter antenna" does well for local Hawaii state nets, with the horizonal element contributing some high angle radiation.  The vertical element seems to do well to the U.S. west coast from Hawaii Island.  Like the designs of McCoy and La Barge, the use of open wire feeders allows the antenna to cover 80 to 10 meters.  As is the case for many compromise antennas, performance will not match that of a tri-band beam on a 50-foot tower.  But, for my purposes, this limited space antenna is easy to build, can be hidden if necessary, and can be used for portable operations.  This antenna may be what you're looking for.

Have a good weekend!

Aloha es 73 de KH6JRM--BK29jx15