[TowerTalk] 160M Wire Antenna

[Tom Rauch]

> I'd agree that the MAXIMUM radiation is straight up, but a 160 meter
> inverted vee with the apex at 100 feet and the legs 90 degrees apart
> is only 5 db down at a 30 degree takeoff angle.  Not as good as a
> vertical over perfect ground, but not too bad either.  Lots of DX can be
> worked with that.

Hi Bill, 

Let's look at the FS of a vertical on 1 MHz at zero degrees on the 
modeling programs amateurs generally use. 

Now turn on your radio, and listen to the AM band even using a 
very poor vertical. 

Do you hear all those dozens of stations on groundwave that are 
way off on the horizon, some of them 50 miles or more away? 

If the zero degree radiation is as poor as predicted, how can your 
vertical (with its almost ZERO response at zero degrees) hear their 
vertical (with an almost zero signal at zero degrees) during the 
daytime on groundwave???

If verticals actually worked like the programs might make us think, 
the BC band would become dead during the daytime.

Fact is, you can work some DX with a low dipole...but the 
conditions better be good and there better not be someone with a 
good vertical wanting to work the same DX station. Decent verticals 
absolutely are many many  dB better than low dipoles for DX the 
majority of the the time on 160, and quite often on 80.

As you go up in frequency, the results get more like you might 
expect looking at the programs.

> Another interesting characteristic of inverted vees is that when the
> apex is roughly 1/4 wavelength high or less, they are almost perfectly
> omnidirectional in the azimuth plane.  There is no "donut" pattern typical
> of horizontal dipoles.  This is not always desirable, but it does mean
> that you can orient it any way you like without having to worry about
> either favored or null directions.

That's true for a low dipole also. There is very little difference in 
pattern between an inverted V dipole and a regular dipole, except 
the inverted V dipole acts like it is mounted a bit lower.
73, Tom W8JI
w8ji@contesting.com

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