Re: Topband: Ground mounted 1/2 wave

["Tom W8JI" <w8ji@w8ji.com>]

> > **  All that means is that the elevation peak of the wave as seen in the
> > typical 2D plot increases by .38dB and as expected. It does not say what
> > happens from that peak down to zero elevation which is what 160M DXers 
> > care
> > about.
> > What is the FS at 5, 10 degrees when going from a ground rod to a full
> > bore radial field over a wide range of ground conductivity?
> > Carl
> > KM1H
> Yes, it does say what happens from that peak down to zero elevation. It
> says that the signal increases by 0.38 dB.
>
> To test this I ran two EZNEC simulations. One is a 90 degree vertical over
> thirty 90 degree radials over medium ground. The antenna is driven with 1
> kW and the E-field at one mile is recorded from a height of 10' to 1000'. 
> A
> second 90 degree vertical over four 23 degree radials driven with 1 kW and
> the E-field at one mile is recorded from a heights of 10' to 1000'. *The
> difference in E-field AT ALL ELEVATIONS is 0.86 dB*.
I have the same or similar results here, and that is the same or similar to 
real life antennas.
There pretty much is always <1 dB available to wring out of a half wave 
vertical no matter how many practical radials or screens are added.
This isn't saying there can't be more than 1 dB when the original system has 
a serious flaw or uses a terribly inaccurate measurement protocol, but 
rather a case of good methods and proper installations.
For anyone wanting to use a common readily available program and get rid of 
far field "flat earth" losses locked into the program, use a detector 
antenna with a load to measure power 2,000-20,000 feet away.
I think this thread has gone to the limit, because the argument is between 
emotional conviction laced with constant personal insults and science. All 
this can do now is repeat with the same discussion methods.
73 Tom 

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