TopBand: JT1X - Topband experiences

[Tom Rauch]

VE7BS Bob sent me this:
> Date:          Tue, 23 Jun 1998 09:43:13 -0700
> Seems to me the popular misconception is that "noise is vertically
> polarized" rather than "is an electric field". So when you say "they both
> have the same characteristics" people may assume you mean all the
> characteristics on arrival at the antenna, so a given antenna will respond
> equally to both signal and noise.

I might not have made the point well. Actually ALL antennas respond 
the same way to far-field noise IF the polarity of the noise and 
signal and direction of arrival  is the same. There is a popular 
misconception that loops are less responsive to noise because they 
are "magnetic" or dc grounded and noise is an "electric field", as 
well as the popular wive's tale Bob pointed out.

> But you will agree that if the noise has travelled parallel to the earth for
> a distance, the horizontally polarized signal (in loose terms "a horizontal
> electric field") will have been attenuated, and the noise then appears to be
> vertically polarized.

That's a good point, and probably where the rumor a dipole is quieter 
for distant QRN came from . Only local groundwave propagated noise is 
predominately vertically polarized, because horizontally polarized 
signals are greatly attenuated as they follow the earth. Sky wave 
noise is either polarity! 

My 4 square is consistantly quieter than a dipole during the summer, 
but not for groundwave noise coming from a few miles away!
73, Tom W8JI
w8ji.tom@MCIONE.com

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