Roy, I use a couple of methods. First, the RP card as follows:

RP 0 19 73 1002 -90 0 5.0 5.0

Where, the last digit of "XNDA" is "2", and the average gain
is calculated providing the following output:

AVERAGE POWER GAIN= 3.00224E-01 SOLID ANGLE USED IN AVERAGING=( 2.0000)*PI
STERADIANS.

POWER RADIATED ASSUMING RADIATION INTO 4*PI STERADIANS = 1.15944E+01 WATTS

The input power for this particular test was 38.619 W.

As a verification I numerically integrate (Excel) the total radiated E-field
over a hemispherical region.
The elemental area I use is r^2*sine(theta)*d(theta)*d(phi). Of course
the E field is normalized to 1 m, and "r" is obviously "1". d(phi), and
d(theta) are both one degree.
The results are in very close agreement with the radiation, as above,
in 4*PI Steradians/2. I therefore have a fairly accurate figure for
the total radiated power without the surface wave.

For the next step I use the following RP card:
RP 1 101 1 0000 200 0 -2 1 200. The problem is, of course,
that the results are only available in cylindrical coordinates.
Where the total ground wave, and sky wave, is computed in the far field
(Where I have taken the far field to be 200 meters at 8 MHz)
from Z = 200 to Z = 0, in steps of 2 meters (From theta(zenith) 45 to
90). I then normalize these data to a radial distance of 1 m; taking only
those data points close to (theta) integral degrees. Picking out
these data points, taken from the NEC output file, in Excel is a
fairly tedious process. I then "cut and paste" these normalized
data into my "integrating" Excel spread sheet; replacing the
previously computed "sky wave" data from 45 to 90 degrees.
These results then give me the total radiated power, including
the surface wave. I can then easily compute the contribution,
to the total radiated power, by the surface wave.

When I replace the data, in the integrating spread sheet, the data
at 44 degrees is very close to the 45 degree field strength, obtained
from the cylindrical coordinates.

Hope you managed to follow my rambling description. To say the
least it requires a lot of tedious data manipulation with Excel.
If you are interested I can e-mail my spread sheets, NEC input
and output files, etc.

Regards,

Frank (VE6CB)


"Roy Lewallen" wrote in message
...
I'm curious: How did you calculate the total radiated power including
surface wave, and how did you determine what fraction of the radiated
power is in the surface wave?

Roy Lewallen, W7EL

Frank's wrote:
. . .
Note that the radiation resistance is computed
from the total radiated power (including surface
wave) divided by the RMS base current squared.
. . .