"Frank's" wrote in
news:4OxZh.8833$Dq6.8346@edtnps82:


"Owen Duffy" wrote in message
...
"Frank" wrote in news:u9qZh.14500$JF6.4868
@edtnps90:

Owen, It may not be too critical, but would not the
Sommerfeld/Norton method improve accuracy?

Hi Frank

My understanding was that the MININEC ground model was the better to
use if
the model caused current to flow into ground (as mine does).

The draft model is at
http://www.vk1od.net/multibandunload.../13MVERT01.nec if you
want to
play with it.

Owen

I was not thinking Owen. I forgot that some versions of NEC support
the MININEC
ground. I have loaded your program, but noticed my version of NEC
does not support a "GN" entry of "3" in the "I1" field. It thinks it
is a Sommerfeld/Norton
ground, but does not recognize the conductivity and permittivity
fields. About the
only way I could get the program to run is to extend "GW 10" below
round --
at a guess about 5 segments should be ok. I am also concerned about
some discontinuity with the large diameter change from GW 9 to GW 10.
Also GW 1 to GW 2. Initially I will set all diameters to 1 mm, and
see what I get by
running the AVG test.

Hi Frank,

I built the models in 4NEC2 and EZNEC, both using the MININEC ground
feature.

My guess is that the radials are far enough clear of the ground that NEC-
2 should be adequate for modelling, but it would be interested to see
what results you get from NEC-4.

Re extending wire 10, don't forget it is loaded, so you need to deal with
that.

Owen