ETS-Lindgren HI-4456 Isotropic Electric Field Probe (Archived) - Manual (Page 26)

HI n 4456 Manual Page — 21
7.0 APPLICATION CONSIDERATIONS
Introduction
The following subsections contain information designed
to help you maximize the effectiveness of the HI n 4456.
Out-of-Band Considerations
Although the HI n 4456 is nominally rated for operation
from 300 MHz to 18 GHz, it may respond to signals both
above and below these frequencies. Such responses
must be taken into account when performing certain
operations, such as zeroing.
On the lower end, the HI n 4456 can exhibit significant
response to frequencies below 300 MHz. Such out-of-
band responses may pose a problem when zeroing the
unit, since that operation assumes a zero field condition.
At the upper end, similar problems may occur.
Resolution Limitations
Limitations in probe resolution may result in a non-zero
reading when the receiver is zeroed. If this occurs, it
does not necessarily mean either that there is a problem
with the receiver or that your readings are inaccurate.
Receiver linearity is specified as + 0.5 dB full scale: in
addition, the variance of the A/D converter is + 2 least
significant bits. When using the most sensitive range on
a given probe, these specifications create the possibility
that, under zero field conditions, the receiver may display
a non-zero value.
Probe Support Structures
It is very important to keep conductive objects away from
the HI n 4456. Any such objects in the proximity of the
probe may distort the near field and compromise
measurement accuracy. If your application requires
Archived 4/2/10