Re: NEC-LIST: MW Broadcasting Arrays with NEC2

Sylvio:

My advice is to measure (or have measured) the ground constants at the
site under different conditions of soil moisture. I use my
Open-Wire-Line (OWL) kit for such measurements, and I artificially wet
the soil to near saturation to establish a worst case on max moisture
content. What is your frequency? I have done MF measurements at a
variety of Voice of America (VOA) sites around the world, and maybe
one is close (by soil type) to the case you are interested in. Another
thing to do is model for the different cases of ground constants
available in NEC, and look at the sensitivity of the output to the
differences in input.

(You may need a version of NEC with the SOMNEC (Sommerfeld) subroutine
in it, which only a few versions of NEC-2 have.)

George Hagn

Sylvio Mauro Damiani wrote:

> Hello
>
> Does anyone has experience in dealing with, say, a two-tower
> MW array with elevated radials (paralel to soil)?
>
> The problem is as follows: to synthesize an array in order to
> meet the FCC specifications, i.e., meeting a previous and specific
> magnitude and phase relationship for the space Field, etc, by using
> NEC2 engine? Are the electrical parameters also determined? (such as
> power division between towers, expected base input impedance for each
> tower, etc). Another question, which kind of ground (between the
> options presented by NEC2) is supposed to present the best or nearer
> results when compared with measured final values of input impedances
> and space Field magnitude and phase? Is there any way of determining
> the Current Moments envolved with the radiating elements?
>
> I thank in advance to anyone who can help me.
>
> Sylvio M. Damiani,P.E.
> Sao Paulo, Brazil
Received on Fri Jun 26 1998 - 13:45:01 EDT