View Single Post
  #12   Report Post  
Old May 1st 07, 03:42 AM posted to rec.radio.amateur.antenna
Frank's Frank's is offline
external usenet poster
 
First recorded activity by RadioBanter: Dec 2006
Posts: 44
Default Effectiveness of decoupling radials


"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.

Frank