Page 2-28
ATU-HP Technical Instruction Manual
Issue 2.0
Section 2 Preparation for Use and Installation
2.6 INCREASING ANTENNA
BANDWIDTH
If it is necessary to increase antenna
system bandwidth, as determined in
paragraph 2.5, step (z) for DGPS
applications or step (aa) for NDB
applications, incorporate the Nautel’s
Series Resistor Kit, if provided, as follows:
NOTE
The series resistor kit is factory installed if
purchased with the ATU-HP. The kit is
user-installed, using a separate
Information Sheet document, if purchased
after ATU-HP installation.
Adding series resistance will reduce the
reflected power level, but will reduce
antenna current.
WARNING
It is recommended that additional safety
precautions against accidental RF input
application be taken when working in
the vicinity of the tuning coils.
Connect grounding clip (located near
the RF input) to the RF input.
(a) Using Figure 2-14a (for DGPS
applications) or Figure 2-14b (for NDB
applications), determine the additional
series resistance by selecting the T2
tap settings that provide acceptable
reflected power. View reflected power
on the ATU control/monitor PWB’s
meter, noting switch A1S10 must be
set to
REFLD PWR
and switch A1S11
must be set to
RF POWER
.
