N7mal wrote:
>----- Original Message -----
>From: N7mal
>To: John Geiger ; towertalk@contesting.com
>Sent: Sunday, April 05, 2009 23:55
>Subject: Re: [TowerTalk] Vertical vs Beam
>
>
>I have been following this thread with great interest. I'm curious how many
>of the guys who have responded have ever built and/or used a 1/2 wave
>vertical,,, other than me.....
>One guy said:""1/2 wave vertical won't show any gain over a quarter wave
>vertical unless it has a much larger
>radial system"".... First of all a 1/2 wave vertical is a voltage fed
>antenna therefore it doesn't want/need or like a radial system. The current
>portion is 1/4 wave above the feedpoint. Because the 1/2 wave vertical is a
>1/2 wavelength it will automatically have gain over a 1/4 wave vertical.
>
>
WWV uses 1/2 wave verticals:
http://tf.nist.gov/timefreq/stations/wwv.html
http://tf.nist.gov/timefreq/general/pdf/271.pdf
Interesting design with the 9 wire skirt. They mention in the old QST
article that connecting the tower bases to a ground radial system didn't
perturb the antenna's input impedance.
>There were several comments about the """"horrible/terrible"""" noise a
>vertical hears and they are useless for receiving.
>
This is only true if the noise sources are local. For skywave propagated
noise, the polarization is randomized so on average it shouldn't make
any difference (the pattern differences will in certain instances come
into play depending on the angle of arrival differences between the
noise and the desired signal). BTW, I have a 20 meter 1/4 wave ground
plane at my home QTH. It is VERY noisy, but I am in the city. The noise
is all local (I just checked to be sure - it doesn't get quieter when
the band dies at night). When I had a 80 meter inverted-vee dipole up,
it would almost always produce a weaker s-meter reading on 20 meters
(due to the impedance mismatch loss), but more often than not it
provided the better overall SNR.
73, Mike W4EF...................................
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