05-4819A01, Rev. 08
LCT 450 Installation/Operation Guide
17
When this happens, the radio must be commanded back to an unkeyed
state before a new keying command is accepted. The default timer
value is
30
seconds.
VERSION
Firmware Version
Displays package version information for each firmware image.
RADIO TESTS & TEST MODE COMMANDS
The following are checks and settings that can be performed by a tech-
nician to ensure optimal performance of the radio. For most tests, it
will be necessary to connect a PC to the radio as described in
SOFT-
WARE COMMANDS on Page 5
.
Antenna System SWR Check
SWR is a parameter related to the ratio between forward trans-
mitter power and the reflected power from the antenna system.
As a general guideline, reflected power should not exceed 10%
of the forward power (
≈
2:1 SWR). A high SWR may result in
decreased performance, and should be corrected.
The transceiver’s
TXD/RXD
LEDs will light when the SWR is too
high. Actual SWR can be measured by connecting a reflected
power meter, such as a Bird Model 43
™
directional wattmeter
with the proper element installed, between the transceiver and
the antenna system. Use the
KEY
/
DEKEY
commands described
below to control the transmitter during these tests. Test transmis-
sions should be kept as brief as possible.
If the results are normal, record them for comparison during
future routine preventative maintenance. Abnormal readings
indicate a possible trouble with the antenna or the transmission
line that will need to be corrected. Look for cable damage, poor
connections, or improper positioning of the antenna (such as
having the antenna whip too close to a metal surface).