Saturday, March 31, 2012

Simple Antennas for the Hawaii Island Amateur Radio Operator--a continuing series of personal observations

It's been awhile since I jotted down a few notes about antennas.  This is one of those cases where "one should be careful about what you wish for."  Until March, most of Hawaii Island was gripped in an extended drought which began 3 years ago.  Although West Hawaii (including Kailua-Kona) has been struggling with a prolonged dry spell for several years, those of us living on the windward usually received sufficient trade wind showers to stave off any water shortages.  Until March, many East Hawaii residents got by with diminished water supplies, hoping that the weather would change.  March has turned out to be quite wet on the windward side, with rain totals in Hilo exceeding 25 inches for the month.  All of this moisture was accompanied by strong 20 to 30 mph winds, mudslides along major highways, and several power outages.  As April Fool's Day approaches, the weather is improving and only scattered showers will herald the arrival of our spring season.

During the past few weeks, heavy rains and windswept branches have damaged most of my verticals (40-meter inverted vee and the 20-meter vertical dipole).  Fortunately, the 40-meter loop under my home served as an excellent emergency antenna, especially for monitoring local hf nets.  The loop pushes a good signal out to 300 miles or so, just enought to cover the islands from Hilo to Lihue, Kauai.  I will be restringing the wires on the vee and the vertical dipole--a task that will occupy a few days with my current teaching schedule.

Meanwhile, I've been able to erect a simple vertical that keeps me on the air.  I have a large tree on the border of my rental lot which serves as the terminus of a 135-foot "long wire" I shot over the tree with a slingshot.  The wire is attached to my Drake MN-4, with a counterpoise connection to the 40-meter loop under the house.  I also have the ground lug of the MN-4 connected to a small radial field in the yard (three, 33-foot radials laid out on the ground).  So far, this crude system works and I get no rf in the shack.  The efficiency of this "skyhook" is probably poor, but I do get out and I do get some moderate DX (Japan, Korea, Philippines, and sometimes Europe).  I can work 80 through 10 meters with 10-20 watts from the old Swan 100-MX (cw).  This "lashup" antenna will serve my immediate needs until the other verticals are rebuilt and erected.  Never a dull day at the radio ranch.

Have a good weekend!  It could be worse--I could be organized.

Aloha es 73 de KH6JRM
Laupahoehoe, Hawaii--BK29jx15.