Return to KLUBNL.PL main page

rsgb_lf_group
[Top] [All Lists]
<prev [Date] next>
[Advanced]
 <prev [Thread] next>

Re: LF: Field strength calcs.

from [Dick Rollema] [Permanent Link][Original]
To: [email protected]
Subject: Re: LF: Field strength calcs.
From: "Dick Rollema" <[email protected]>
Date: Tue, 08 Jul 2003 14:54:46 +0200
In-reply-to: <[email protected]>
References: <000001c343db$8cb86760$5967fea9@p4o2b7>
Reply-to: [email protected]
Sender: <[email protected]>
To All from PA0SE

Jim, M0BMU wrote:


The voltage induced in a loop is:

V = 2.1x10^-8 (fNAE)

where f = frequency (Hz)
        N = number of turns
        A = area (m^2)
        E = field strength (V/m)

Always assuming that the antennas are far enough apart for the loop to be in the "far field" (>1 - 2km seems to be enough)

I think 2km is not quite enough at 73kHz. I calculated the total field over perfect ground at 2km distance by means of a antenna simulation program. I found E/H = 342 ohm. In the far field E/H ought to be 377 ohm  (= 120.pi ohm).  So apparently at 2km the near field is not yet small enough to be negligible. 

I found that even at 137kHz measurements were inconsistent at 2km so I changed to over 4km. 

73, Dick,  PA0SE
[More with this subject...]
<Prev in Thread] Current Thread [Next in Thread>
Previous by Date:  LF: re T/A path Propagation, Alan Melia
Next by Date:  LF: TA Again, Joe Craig
Previous by Thread:  Re: LF: Field strength calcs., dj9dw
Next by Thread:  Re: LF: Field strength calcs., James Moritz
Indexes:  [Date] [Thread] [Top] [All Lists]