Topband: Quarter wave Vs Eigth Wave

[Wes Attaway (N5WA)]

It is pretty obvious that the models predict some things a lot
more accurately than other things.  Tom's "warnings" attempt to
address the issues associated with the particular situation of
trying to model performances of vertical antennas (particularly
TOA) over real ground, given that ground conductivity is neither
known nor a constant in most locations.  A model might give
fairly accurate results if the ground conductivity is known with
certainty, and if the conductivity is the same for many
wavelengths in all directions.  Apparently, these conditions are
rarely met in real life.

Modeling a yagi 2 or 3 wavelengths above ground is a different
situation.

Modeling is certainly a worthwhile exercise, but in the case of
verticals trying to pick one antenna over another based on
something as slim as 1 or 2 Db of predicted difference at a
certain TOA may be a big mistake.  I think this is all Tom was
trying to point out.


-----Original Message-----
From: topband-bounces at contesting.com
[mailto:topband-bounces at contesting.com]On Behalf Of Pete Smith
Sent: Sunday, April 20, 2003 3:42 PM
To: Tom Rauch; Rick and Angela; Topband at contesting.com
Subject: Re: Topband: Quarter wave Vs Eigth Wave


At 11:11 AM 4/20/03 -0400, Tom Rauch wrote:
>The person quoted (W4RNL) doing the modeling very clearly warns
it is only a
>comparison of one model to another model and the models do not
in any form
>represent real conditions. He, in essence, warns of all the
things we are
>discussing.


If the models don't represent real conditions, why bother?  The
whole idea
of modeling is to predict how physical systems will operate in
the real
world.  If the results are meaningless....

73, Pete N4ZR
Sometimes a tower is just a tower

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