LAPLACE INSTRUMENTS RF200 User Manual - page 10
RF200/500 user manual
10
If using a an open field test site, this should also be calibrated. The ground plane
reflection alone can have a significant effect on the test results. To calibrate a site, a
known source should be used. Laplace can supply a calibrated source, complete with
calibration curves, which is specifically designed for the calibration of sites and
antennas. Contact Laplace for details of this ERS (Emission Reference Source). An
alternative for achieving a rough calibration is to use a product with known emissions
(i.e. one which has already been tested at a test house) on your test site under exactly
the same conditions as applied during the test house measurement. By correlation of
your results with the test house results, an approximate calibration of the site can be
derived. Note that if the site is outdoors, it will need a calibration check every time it
is used because weather conditions can affect the site significantly.
Drawbacks to this technique are the problems of obtaining consistent emissions from
a product and the fact that the correlation can only be applied at those frequencies for
which emissions exist.