How to apply correction of van Veen loop?

Discussion and questions regarding the Radiated Emission and Conducted Emission modules of RadiMation.
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incognito
Posts: 235
Joined: 03 Feb 2012, 13:07

How to apply correction of van Veen loop?

Post by incognito »

I perform a van veen loop measurement as it is described at: https://forum.radimation.com/viewtopic.php?f=6&t=68
I'm using the Laplace instruments RF300 loop antenna. https://www.laplace.co.uk/systems/magne ... veen-loop/

That is working ok, but I do have some doubts on the best method to apply the correction for the antenna. What is the best method to apply a correction of loop antenna?
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joro
Posts: 440
Joined: 24 Aug 2011, 09:55
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Re: How to apply correction of van Veen loop?

Post by joro »

It is indeed correct that in the documentation of the Laplace RF300 (https://www.laplace.co.uk/wp-content/up ... MANUAL.pdf ) is written that the antenna factor should be applied when measurements are performed with the antenna for the CISPR16 measurements.

We suggest to use the conducted emission multiband test, with a location type of 'Current Sensor'. That test method represents the test data in dBuA units, which match the unit in which the limits are specified in CISPR16.
This 'current sensor' test method uses the following equipment from the testsite:
  • current sensor (required)
  • cable antenna -> preamplifier (optional)
  • preamplifier (optional)
  • cable preamplifier -> spectrum analyzer(optional)
  • spectrum analyzer (required)
The 'Current Sensor' location type uses the 'current sensor' as the coupling device. However still the cable between the antenna and the preamplifier is used as is the case with any other emission test. The device selected as the 'antenna' in the testsite is not used at all when the 'current Sensor' location type is selected.

The current sensor, which is the van Veen Loop antenna in this case, can be corrected, however it only allows that the impedance of the current sensor device itself can be corrected. And this correction is expressed in Ohm. This correction can thus not be used for the correction of the loop antenna which is expressed in dB by several manufacturers.

In the manual of the RF300, it is explained that the Antenna Factor of the loop antenna should be added to the dBuV values that are measured by the receiver, to get values expressed in dBuA. This antenna factors are frequency dependant and are fluctuating between +12 dB to -29 dB.
The easiest solution is to create a RadiMation correction file with a 'Frequency' and a 'Correction' column. Then include the antenna factors as specified for the van Veen loop in that correction file.
The correction file can then be attached to a cable device driver, where that cable device driver can be selected in the testsite as the 'Cable Antenna -> Preamplifier'.

This configuration will correctly correct the antenna factor of the van veen loop, and will result in the correct measurement result expressed in dBuA.
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