John.
Fascinating stuff and all your are papers duly saved. I sort of knew PA0SE
must be right and while E/H = 377 ohms between the Helmholtz coils, we have
to go to the far field of an antenna before a "plane" wave is sufficiently
well formed and once again E/H = 377 ohms. Thanks for the clarification.
73 Malcolm.
----- Original Message -----
From: "John Andrews" <[email protected]>
To: <[email protected]>
Sent: Thursday, September 27, 2007 8:40 PM
Subject: Re: LF: A question of calibration
Malcolm,
Hi. Can anyone reassure me.
Be reassured. Your meter is measuring the magnetic field, and the
calibration setup is primarily generating a magnetic field. The cal is
being done under near-field conditions to permit the use of low power and
take advantage of knowing the mag field accurately based on geometry and
current measurement. The scale conversion to electric field remains valid
as long as you agree to take your real measurements under far-field
conditions.
A further discussion of calibration techniques including a simpler
arrangement than Helmholtz coils may be found at:
http://www.w1tag.com/LF_FSM.htm
John Andrews, W1TAG
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