ETS-Lindgren HI-1710A Microwave Oven Survey Meter - Manual (Page 26)

26 Operation www.ets-lindgren.com
The analog bar graph display may be used to determine areas of highest
leakage. In the normal mode (not Peak Hold) the bar graph display will track the
displayed digital value and respond to the filtered RF signal. When the instrument
is operated in the Peak Hold mode, the bar graph display is not filtered and
responds very rapidly to changes in RF intensity. The Peak Hold mode may be
used while scanning to capture the area of highest leakage, while the bar graph
will continuously display instantaneous variations in leakage.
Changing the filter selection to FAST will decrease the response time of the
system. This will more effectively show the effect of rapid variations in RF levels
due to mode stirrers or other modulating devices. In both the SLOW and FAST
filter positions, the response time meets the CDRH requirement for RF
measuring instrument response times while the SLOW response characteristic
provides maximum smoothing of RF variations.
After the test is completed and the RF reading recorded, zero the HI-1710A
again before the next test. The zero point may gradually drift over long periods.
Re-zero before beginning a test.
Connecting and Using the Zero Receptacle
The zero receptacle should be located in an area that is relatively free
of significant RF fields. The fields near the zero receptacle should be
checked periodically to confirm that no significant stray fields are
present.
1. Attach the cable to the ZERO BNC connector located on the back of
the HI-1710A.
2. Attach the other end of the cable to the connector on the side of the
zero receptacle.
The zero receptacle is most often used with Peak Hold mode. When scanning an
oven in Peak Hold, the highest reading is displayed on the HI-1710A. When the
probe is inserted into the zero receptacle, the RF reading is sent to the RS-232
serial port for automatic data collection and the probe is zeroed.
For manual data recording, the RF reading must be recorded before the probe is
inserted into the zero receptacle.