I agree, Guy. Having learning & using 3 modeling programs with various NEC
engines, and after sitting down with an engineer friend who has one of those
expensive modeling programs ($1000s), the "comparisons" I've concluded are
that (1) modeling programs are simply a starting point and that nearly
always I've had to put it up, prune/extend/move nearly as many times as the
"old days", (2) some antennas model/predict much better than others in these
programs (eg, yagis=good, certain wires=poor), (3) the pro program(s) is
*much* more accurate than the "affordable" & freebie ones, (4) modeling is
great for filtering out the junk designs before building, (5) modeling helps
most people learn more about antenna/transmission line/balun-unun theory,
albeit requiring a great deal of patience & time to do so (primarily because
of poor UI, usability, and doc). I now always use a modeling program, but
for antennas it's definitely not "design, build, and it works first time".
That coming from a EE who's built antennas since a teenager and now what
little hair I haven't pulled out is grey :-)
FWIW IMO,
Stephen W9SK
-----Original Message-----
From: antennaware-bounces@contesting.com
[mailto:antennaware-bounces@contesting.com] On Behalf Of Guy Olinger K2AV
Sent: Sunday, March 07, 2010 10:59 AM
To: DAVID CUTHBERT
Cc: antennaware@contesting.com
Subject: Re: [Antennaware] Modeling
On Sun, Mar 7, 2010 at 12:56 PM, DAVID CUTHBERT <telegrapher9@gmail.com>
wrote:
> Modeling of antennas? Design, build, it works as modeled.
I have all the scars and memories of wasted time that would prove otherwise.
Take models as gospel, and it will get you sooner or later. Don't go
investing any of my money in unverified models.
With respect to the behavior of RF in and around dirt, we only have
approximation methods. Certain persistent excellent anecdotal reports in
antennas simply does not come out in the models.
Measure, measure, measure, measure....
Verify, verify, verify, verify, verify....
Record, record, record, record, record.....
73, Guy.
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