RE: NEC-LIST:NEC-BSC question

Howdy,

Picking nits, here. The equation is right, but it's a little misleading to
describe the denominator as "twice the impedance of free space." Both
NEC-BSC and NEC-MOM give E-fields in peak volts. Converting peak to rms is
E/1.414, so when that is squared, it becomes |E|^2/2. The two in the
denominator is related to the volts and not to the impedance. I still get
trapped every once in a while by that peak/rms thing if I'm doing a manual
calculation to check NEC-whatever.
73's
Smilin' Chuck

At 04:46 PM 3/27/2002 -0500, you wrote:
>I'm not sure what input value you're referring to. For the SI:
>command, it is dB-whatever. The output is simply scaled by the
>input which allows the user to select a meaningful level (i.e.,
>scale your inputs to represent dBi, or dBW or dBm/m, etc.).
>
>The output is in radiation intensity (see pg 30 of the 4.2 manual).
>It is the magnitude of the E-Field squared divided by twice the
>impedance of free space (|E|^2/(2*377)).
>
>So, 10*log(214*214/(2*377)) = 17.8 dB.
>
>Read the Output Section starting at page 20, pg 30, and the PR
>section of the manual for information of scaling this to other
>values.
>
>Rest assured you're not being dense. Most people have trouble
>digesting this.
> ---Paul
>
>-----Original Message-----
>From: Richeson, Peter D [mailto:peter.d.richeson_at_boeing.com]
>Sent: Wednesday, March 27, 2002 1:06 PM
>To: 'NEW NEC list send'
>
>Reading the documentation that came with Ver. 4.2 I am having a hard time
>knowing for sure what the units are. It lists a switch to tell the code
>that the input is in dB. dB what? dBW, dBm, etc. When using the VF
>command, the output lists mag, phase and dB. again dB what. For example:
>one lines lists the mag as 214 and the dB as 17 (approximately). Maybe I am
>being dense but this does not make since.
>
>Thanks.
>
>Peter D. Richeson
>Electrical Engineer/Nuclear Survivability Specialist
>(405)739-1879
>--
>The NEC-List mailing list <nec-list_at_gweep.ca>
>http://www.gweep.ca/mailman/listinfo.cgi/nec-list
>

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