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Re: LF: <Tech> More on Antenna Loss

To: [email protected]
Subject: Re: LF: <Tech> More on Antenna Loss
From: "Rik Strobbe" <[email protected]>
Date: Wed, 31 Oct 2001 11:35:28
In-reply-to: <[email protected]>
Reply-to: [email protected]
Sender: <[email protected]>
Hello Jim & group,

G3NYK (6m high, 30m long inv. L): Rloss = 4733/f^0.86 (for points below 600kHz only)
M0BMU(8m high, 40m long inv. L): Rloss = 1550/f^0.75

ZL2CA(Don't know, but must be quite big!): Rloss = 142/f^0.50
While doing research for my LF antenna webpage I came across a formula the
gave the pentration depth of an E-field in the soil as :

D = 509/(S^0.5*F^0.5) where D = depth in m, S = soil conductiviy in S/m and F = frequency in Hz
Assuming the the ground loss is proportional to the distance 'traveled'
through the soil the results of Bob (ZL2CA) seemed really a textbook case
compared to the measurements of Jim (MBMU) and Alan (G3NYK), so I wonder if
the 2 last do suffer more from additional losses (buildings and greenery
close to the antenna) compared to Bob ?

BTW : The emperical equations are a bit dependent on the frequency range
you take. For Jim's measurements I get R = 1555*F^-0.75 for the whole range
but then I took only the points between 100 and 300 kHz (to have the same
range as Bob) and got R = 1830*F^-0.79.

73, Rik  ON7YD


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