Ken,
This data was not taken with 61000-4-3 primarily in mind. We do -4-3, but also
MIL, RTCA, and ISO testing. I should have had the probe at least 15 cm for ISO
or 30 cm for MIL like you said, but 10cm is how I took the data.
Uniform field calibrations will be a concern eventually, but the
Where below I said the measurements were within 6 dB of each other, I should
have said 3 dB. I got confused and was thinking of the values as field
intensities, not the power required to achieve a given field intensity.
Ken Javor
Phone: (256) 650-5261
From: Ken Javor
Certainly below 1 GHz these probes are calibrated in a TEM cell with field
orientation parallel to the sensing element. Call it far field if you will,
but the point is that the sensing element is electrically short and drives a
high impedance capacitive load to get flat performance over the wide
All,
Thanks for your all your input.
I don't think the listserve allows attachments, so I can't share setup photos.
The setup was like that used for RTCA, MIL STD, or automotive(ISO 11452-2). 90
cm high, appeox 3.5 meters long copper bench bonded to the chamber wall. I have
only done this
In turn:
It is not surprising at all that it takes less power to generate the
vertical field than the horizontal field. That¹s the effect of the
conducting ground plane. The OP doesn¹t say what spec they are working to,
but that is why MIL-STD-461 below 1 GHz has the probe 30 cm above the ground
I'm with Gert.
Anything "antennas" is checked in the far-field -- especially if
testing for accuracy.
I'm a BIG fan of near-field probing for relative measurements and
localizing emissions, but we use probes appropriate to what we are
looking for; if I wanted to "calibrate" one there,
IMHO all probes are calibrated under far field conditions.
In general: Using probes in the proximity (< lambda) of anything
conductive (including ground planes at 10 cm and including EUT) makes
the measurement data useless.
As James correctly states, the construction of the probe makes this
Hi David,
An interesting set of results! I'm going to ask some questions that I'm sure
you've already considered so please bear with me being Captain B. Obvious.
Do your field probes use frequency correction? I'm not familiar with a wide
range of probes but my Narda PMM field probe has an
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