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[TowerTalk] Re: Guy wire interaction

To: <towertalk@contesting.com>
Subject: [TowerTalk] Re: Guy wire interaction
From: n7cl@mmsi.com (Eric Gustafson)
Date: Fri, 9 Apr 1999 09:29:52 -0700

Hi Tom,

>From: "Tom Rauch" <w8ji@contesting.com>
To: <towertalk@contesting.com>
>Date: Thu, 8 Apr 1999 22:17:53 -0400
>

Snip...

>> In fact, EZNEC does provide for accurately modeling reactive
>> complex network loads.  In the "loads" entry widow, you must
>> specify "laplace" for the load type.  This will delete all
>> current loads.  Then you can enter the load parameters as
>> capacitance, inductance and resistance values (either in
>> parallel or series as appropriate).  The main advantage of
>> this entry method is that the net reactance will be correctly
>> reevaluated for any change in the source frequency.
>
>That makes it easy.  Roy Lewallen also suggested to change guy
>lengths, I try the rescale to a new frequency change.  Say I
>want to shorten the lines 30%.  I just type in a new frequency
>30% higher as a rescale.  Then I type in the old frequency. No
>need to alter the wire tables.
>
>I'm not sure how that would work using laplace loads.

The load reactances will be evaluated at whatever frequency you
run the model.  A frequency rescale will not rescale the load
network component values.

However, besides rescaling the wire lengths, a frequency scale
will also change the diameters.  While this may have a small
effect on the model behaviour, I'd reset the wire diameter after
the rescale for best accuracy.

73, Eric  N7CL


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