[TenTec] 80m antenna suggestion

[ac5e at comcast.net]

Rick, your observations generally agree with mine on NVIS antennas of any sort; whether dipole, inverted V, or loop, over very reflective ground. The experiment I observed used roughly 100,000 square feet of aluminum sheets laid with overlapping edges on very conductive earth. At some heights and frequencies signal strength was substantially enhanced, at others it was just as substantially reduced. Just as both published theory and a little thought on reflections generally says it should. 

But my distaste for low horizontal loops is pretty simple. Besides the extra complexity that makes a large horizontal loop a problem with a postage stamp size city lot - and the further complexity that our water table and therefore the actual reflecting ground layer varies by nearly 40 feet, call that 10 Meters, depending on how long it's been since the last rain and how much water has leaked out of this hill.......

North America is a huge place. And from here, I have a pretty good reach of uninhabited water to my south. So it is a long way to the areas with a really high ham density. 

A low dipole or an inverted V has enough low angle radiation to make a fairly effective antenna over most of NA - and the world when conditions are average or better. But a low horizontal loop is a little TOO directional. 

Taking 80 Meters for an example, 100 miles from here a loop at 25 feet, 8 meters more or less, is usually much the better antenna. 500 miles from here, St. Louis or Charlotte or Tulsa, 19 nights out of 20, the dipole or inverted V is the better antenna. And a vertical is a better antenna still. 

For one instance of many, one night a few years ago I worked EI8S with 5 watts on the GAP Voyager vertical, switched antennas and got the same signal report with 50 Watts to the dipole. But he was inaudible on the 260 foot loop fed with 450 ohm ladder line I had up before they cut the trees I was using for supports. So I'm back to a shortened dipole and a vertical. And frankly, I don't miss the loop at all. 

So it appears that one size does not fit all, any more than one suit fits all occasions. 

73  Pete Allen  AC5E






They are a little too directive.