User Manual

screw and C60 is not fitted). Connect a comms test set to this lead and check that RF
local oscillator power is +17dBm +/- 2dB. Measure local oscillator frequency, this
should be Frx-90MHz(45 MHz for A2,A3 modules). Using a non metallic trimmer tool carefully
adjust the TCXO (X2) frequency until the correct frequency is obtained. Remove the test lead and
solder S3 back in position.
2. Place the high frequency pick up loop in close proximity. to IC1 in order to pick up the
second IF oscillator frequency ( note do not probe directly on the chip as test lead
capacitance will affect oscillator frequency). Adjust CT1 for 89.545MHz (44.545 MHz for A2,A3
models).
3. Inject an RF signal at -80dBm (unmodulated) at Frx into CN5 (Jumper I out, Jumper
J in). Measure DC voltage at VF output SKD-3, adjust L14 for 2.5VDC on this point.
4. Inject an RF signal at -80dBm with standard modulation at Fe, x into CN5, monitor line
RX out and adjust T1 and T2 for minimum distortion. Reduce RF signal level and
check that sensitivity is better than -112dBm for 12dB SINAD.
5. Remove Jumper J and fit Jumper I. Inject an RF signal with standard modulation at
Frx into CN 1, monitor line RX out and check that sensitivity is better than -117dBm
for 12dB SINAD. Repeat test for band upper and lower frequencies.
5.2.3. Power Amplifier Module
Test Equipment:
§ Tested MX800 with PA removed
§ PC with MXTOOLS software
§ RF Power Meter
§ RF Signal Generator
§ Multimeter
§ +13.8VDC 15A power supply
Preliminaries:
* Program upper, middle and lower frequencies of band into 3 channels in
MXTOOLS channel screen. Although the PA will function over a wider
bandwidth, the nominal switching bandwidth of the PA is 10 MHz. The
recommended procedure is to center this 10MHz around the center of the user
frequencies. ( Note that 'Continuous Update Enabled' on the MXTOOLS channel
screen should be ticked for these tests)
¯ Do not connect Exciter RF drive output CN1 to PA.
Procedure:
1. Remove PA top cover. Measure resistance of thermistor between CN4-6 and CN4-4,
this should be approximately 2kfL Connect DC power lead and 10-way connector