4 * Pi * r^2 * |E|^2
Gain = -----------------------
P_in * 2 * 120 * Pi

by using the E-Field magnitude values from nec2's output I get also
those very high values. (?)

PS, also confused by your formula. Which Value of E are you using? Are
you
The formula should be correct:
I just use the magnitude value of the E Field. The intensitiy
W_rad is then 0.5 * |E|^2 / Z_w (E and H are in phase and
orthogonal in the far field)

The radiation density U is then r^2 * W_rad (Unit: Watt per solid angle)

The radiation density U_0 of an isotropic radiator with a total radiated
power P_rad is: P_rad / (4 * Pi).

The gain is then U/U_0 (or in dBi: 10*log(U/U_0) ).

trying to calculate the "Total radiated power" (TRP)? If so you need to
integrate the power density over a spherical region. The calculation is
Yes, but nec2 shows the total radiated power in its output.

As for your RP card, I notice that you are attempting to vary both
"Theta"
and "Phi". I usually keep one fixed and vary the other, but to be honest
I
am not sure if what you are doing is incorrect, although I notice that
the
"Phi" pattern is only computed for one frequency. The only other
difference
No thats no true. In the output file I can see E_phi as well as E_theta
for
every combination of phi and theta (for every frequency).
I use the programm Xnecview to view the pattern and it has problems if you
don't have points over the full sphere.

is that I normally do not use gain averaging. Also using 1 degree
The average gain (over the full sphere) should probably be 1 (or 0 dBi).
I get 0.991.

Thanks for you help! The bad computation was caused by the stupid
segementation I had chosen.

Detlef

Very interesting Detlef. I must admit I did not study the formula too
closely, so will look at it again, to be sure I understand it.

My version of NEC2 has a built in NEC-View utility (NEC-Win Pro), so am not
familiar with Xnecview. I will try your full spherical pattern RP card, and
see if I can run it. When I first cut and pasted your code I was getting
strange FORTRAN code error messages -- something I have never seen before --
and the program was locking up (Windows XP OS). Modifying the RP card cured
the lock up problems. Examination of the segment currents would also
probably have indicated the segmentation problem area. At 1 degree
intervals the NEC output file would be huge, so can see why you chose 5
degree increments.

As for "Total radiated power" (TRP) I assume you mean the "Power budget"
output. I had thought this is only valid for free space computations. With
antennas placed close to the ground the "Power budget" only seems to account
for copper losses. Just a minute, now you have made me start thinking. My
"Network Loss" line in the power budget output always shows zero. Did I
miss something? Do I have to invoke something in the RP card to make
"Network loss" non-zero, and thus arrive at a true TRP. Heck! To think all
this time I have been running Excel numerical integration routines to
determine the TRP.

Regards,

Frank