Just to check ballpark Mutual Z numbers..
for dipoles in free space
>From Kraus, 2nd Ed, page 427
for halfwave dipoles in free space
.25 lambda R21= 40.9
.5 lambda , -12.7
.75 lambda, -24.8 (@ 0.7 lambda) to -18.6 (@0.8 lambda)
Reading off the graph on page 426
@ .25 lambda X21 = 37-j35
@ 0.5 lambda -12-j27
@ 0.75 lambda -22+5j
----- Original Message -----
From: "Denis" <firstname.lastname@example.org>
Sent: Wednesday, February 12, 2003 7:27 PM
Subject: [TowerTalk] Driving Point Impedance
> I have a four in line vertical array for 80 meters that is in
> construction. The verticals are .25 wavelength long and the seperation
> is .25 wavelength. Each has 50 .25 wavelength radials.
> I have measured all the self impedances and the coupling iimpedances
> and from that I have calculated the mutual impedances and the driving
> point impedances.
> The driving point Z are as follows:
> Vertical 1 13 - j17.2
> Vertical 2 17.5 + j5.7
> Vertical 3 36.4 + j21.5
> Vertical 4 80.4 + 60.5
> I have seen numbers for a 3 in line array but no field values for a 4 in
> line array. I was wondering if any one has built and
> measured/calculated the Driving point Z so I could see if I was in the
> ball park.
> Denis Ve6AQ / VE6FI
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
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