View Single Post
  #3   Report Post  
Old September 19th 04, 08:54 AM
Brian Howie
 
Posts: n/a
Default

In message , Roy Lewallen
writes
Gamma-type matches consist of a small loop containing a source. This
type of geometry can be a problem for NEC, and often produces the
symptom you describe. You should have the progam report the average
gain (see the NEC documentation on the RP "card"), and use it to
correct the gain, unless you can rearrange the loop to get the average
gain close to 1. MININEC-based programs don't have this problem with
small loops -- they have other problems instead.

EZNEC users will see the average gain reported at the bottom of the
main window after every 3D calculation, and its meaning and use
described in the manual. However, note that EZNEC normalizes the
correct average gain to a standard value of 1 with or without ground,
while NEC will report a value of 0.5 (or 2, I don't recall for certain)
when everything is ok but a ground is present.


Thanks,

That seems to account for it; -2dB average gain and -0.6db for a
conventional gamma match.

73 Brian

--
Brian Howie