[TowerTalk] K9AY loops-- phased

[Jim Lux]

Some folks might be interested to know that a form of the K9AY loop 
is used as a E/H field probe.

In the idealized form, you have a loop that is split into two halves, 
with a termination resistor in each split.  If you take the sum and 
difference of the voltages across the two resistors, you can measure 
the E field and H field separately (assuming you've picked the right 
resistor value).

In a typical implementation, only half the loop is used, against a 
conductive ground plane (still with a termination at each end).  The 
K9AY is sort of the same thing, except that only one voltage is 
measured (some combination of E and H, then).

For more info
F.Gassmann, J. Furrer, "An Isotropic Broadband Eelectric and Magnetic 
Field Sesnor for Radiation Hazard Measurements", 1993 IEEE 
International Symp on EMC, 9-13 Aug 1993, pp150-109

But Gassman cites:

M. Kanda, "An Electromagnetic Near Field Sensor for Simultenous 
Electric and Magnetic Field Measurements", IEEE Trans on EMC, Vol 
EMC-26, #3, Aug 1984.

There's a pile o' old stuff from NBS about this, too.