[AMPS] Re: TopBand: Beverage

Tue, 11 Nov 1997 11:08:34 +0000

Hi Garry,

> From:          Garry & Yelena <ni6t@best.com>

> Carl:
> 
> NM7M has steadfastly maintained that skews, while demonstrable, are
> rather small (just a few degrees, far too small to be readily measured
> by most of us), but many have noted apparent arrival directions widely
> different from great circle bearings. For example, VK0IR was noted on
> the west coast as coming in from the west or even more northerly, on
> both 80 and 160, although its SP direction was SSW. The sidelobe
> response of a Beverage to horizontal polarization may well explain why
> received signals here have often appeared to be coming from widely
> skewed directions.

I usually  listen on phased loop arrays that have *very* small 
spurious lobes (unlike longwires). 

When the signal skews on the loops, it always skews on the Beverages.

I never find a VK signal good on a SW Beverage but poor 
on the SW loops, some mornings the NW antennas are slightly 
better than the SW antennas, and others vice versa.

When we "look at signals" with our very limited antennas and try to 
guess what is happening, it's sorta like a blind man feeling an 
elephant..except in this case it's more like he's wearing gloves and 
has his nose and ears plugged.. 

Near the earth, your damn lucky to get any horizontally polarized DX 
signal, and if the wave angle is high what the heck does horizontal 
even mean?? When the wave angle is near vertical the electric 
field polarization is always parallel to the earth, and rotates in 
azimuthal compass directions. Along the ground, it is always 
near-vertical.

Our antenna patterns can make us "think" the optimum polarity is 
something it is not. Like the blind man feeling the elephant (with 
his nose and ears plugged), we can only guess what it is.

The only place to measure the true polarity of distant signals 
re-radiated from the ionosphere is in the far field of the earth's 
surface. Otherwise we are measuring the earth's influence more 
than the ionosphere's.

Few of us can put a 300 ft high dipole up, so we have to use 
verticals for low angle signals. The problem is likely much more one 
of wave angle than polarity.

73 Tom
73, Tom W8JI

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