Topband: Fw: GAP VERTICAL QUESTION

[Guy Olinger K2AV]

I have already spoken extensively that your assertion is not proved, NOR is
the counter-assertion proved.  I have no intentions of adding to that.  I
am not persuaded either way, though BOTH sides of that question have
attractive points.  I am waiting for something new to emerge, like
helicopter measurements out 50 km from operational ceiling down to the
ground.  Since the near field NEC4 predicts the notchless 3 or 4 km
helicopter measured data, we have to get it out where the NEC process
predicts the notch and measure it there.  That will settle it.  If it
maintains down to the ground, then we can beat the LLNL people to death
with it and they will have to fix NEC.  Otherwise, we don't know.

To the point in question, you are asserting that if the notch under the
typical far field elevation plot was filled in, THAT would account for the
4 dB?

I give you that the loss would lessen if the gain at the ground was equal
to say 15 degrees and smooth going up, but the integration of the spherical
far field data asserts that OVER HALF THE POWER is going to loss.  The only
way you get that back is to put it over sea water.  Anyone experiencing the
marvelous increase in vertical performance at the edge of/over sea water
will tell you emphatically that you DO get it over sea water and you
decidedly DO NOT get that over inland dirt.  Frankly the difference seems a
lot more than the difference in the plots.

Filling up 20 degrees out of 360 will won't get you back to only 3 dB down.
 The original question still stands.  It is not related to your assumption,
or not.

Anyone wants to tackle the idea that the far field plot of NEC4 is off by 4
dB, in order to keep from acknowledging heavy foreground induced ground
loss, have at it.  It should be interesting.

73, Guy.

On Thu, Dec 13, 2012 at 7:06 AM, Richard Fry <rfry at adams.net> wrote:

> Guy Olinger wrote:
>
>> You can model a near perfect commercial grade radial field, with a radial
>> system apparent series resistance of a few tenths of an ohm, and NEC4 will
>> still come back with an overall loss of 3 to 4 dB.
>>
>
> This is ~true only for a "far field" analysis (as defined by NEC software)
> for a vertical monopole -- which includes the propagation losses present in
> the radiated fields from that monopole, over an infinite, FLAT, real-earth
> ground plane.
>
>