from "Soegiono, Gamal" <[email protected]>
does anyone of you have experience with EZNEC modelling software?
Yes, I do
As far as I know, this is the only software (except for the original but
cumbersome NEC) capable of modelling the ground influence on
antenna feedpoint Impedance as well as on far field diagram AND
incorporating the conductor conductivity.
Most other programs account for ground influence on far field diagram,
but not on feed impedance, conductor losses are omitted.
EZNEC does most of these things quite well, see page 6.9 of 'The LF
Experimenter's Source Book' on Computer Modelling of LF Antennas
It might be worthwhile to simulate antenna arrangements with EZNEC,
using an elevated Radial System. Radials need not have resonant
length, but might be "lengthened" by a radial loading coil in addition
to the vertical radiator's loading coil.
EZNEC cannot model horizontal wires that are closer than .02
wavelengths from the ground so modelling elevated radials could
present a difficulty. As elevated radials are impractical for most of
us there seem little point of modelling them.
EZNEC is also useful for modelling the actual radiated power from the
antenna and was used in the first round of discussions on 'ERP'
(about 14 months ago). The results correlated well with measured
signal strengths.
I first started using K6STI's MN in 1989, which was described in the
first edition of the Antenna Experimenter's Guide. I then moved to
ELNEC, and finally EZNEC, which was described in the second edition
of the Antenna Experimenter's Guide.
In fact I felt so confident of modelling LF antennas using EZNEC that
I gave a presentation at the LF workshop of the LF Convention last
October. I also modelled many of the LF group's antennas and used
them for material at the HF Convention.
'The LF Experimenter's Source Book' and 'The Antenna Experimenter's
Guide' are available from the RSGB bookshop.
--
Regards, Peter, G3LDO
<[email protected]>
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