User manual

Section 3: Installation 3-19
Moseley SL9003Q 602-12016 Revision G
3.5 Transmitter Antenna Testing
After assuring that the SL9003Q is properly installed, attach the transmission line to the
"N" connector labeled ANTENNA on the rear of the SL9003Q. Tighten the connector by
hand until it is tight. Connect the appropriate audio and data cables to the ports on the
rear panel.
After running the transmission line and fastening it in place, connect the antenna end of
the transmission line to the antenna feed line, using a short coaxial jumper and a double
female barrel adapter. Connect the radio end of the transmission line to a wattmeter
(with appropriate frequency and power rating), using the radio feed line and another
coaxial jumper (see Figure 3-7).
Note: Standard Wattmeters are calibrated for CW (carrier) power measurement.
For QAM digital modulation, these wattmeters will indicate approx. 1/2 of the
actual power.
Apply power to the SL9003Q and check the status indications for proper initial operation.
Observe forward power, and check that reverse power is negligible. Turn off power to
the radio.
Exchange the wattmeter with the barrel adapter and coaxial jumper at the antenna end
of the transmission line. Power-up the radio.
Observe forward power to the antenna, and verify that power loss in the transmission
line is within system specifications. Verify that reflected power from the antenna is
negligible. Reflected power should be less than 5% of the forward value, and in most
cases will be significantly less. Turn off power to the radio.
Disconnect the test equipment, reconnect the antenna feed lines, and proceed to link
alignment.
3.6 Link Alignment
It is very important to aim the antennas properly; if the antennas are not aligned
accurately, the system may not operate. An approximate alignment is achieved through
careful physical aiming of the antennas toward each other. The receiver should indicate
enough signal to operate when this is achieved.
Once an approximate alignment is achieved, align the antennas accurately by accessing
the QAM RADIO MODEM STATUS (BER POST) screen and observe the RSL in dBm
(upper right corner of display). This screen also displays Bit Error Rates, which is the
primary parameter for system performance.
Turn the antenna in small increments until the maximum signal is displayed. Please
note that the signal levels should agree with the initial path calculations plus or minus 6
dBm, or there may be a problem with antenna alignment or the antenna system. The
#ERRORS display should be zero, while the #BITS is keeping a running count of the