Product Manual

© MiMOMax Wireless Ltd
Tornado Product Manual
30
3. With TX frequency set to marker 1, Tune 2Tx to peak at marker 1 (note #TX represents the tuning slug and is marked
on the printed circuit board). When tuning ensure that the slug height is not greater than 5.6mm higher than
the printed circuit board, otherwise the slug will contact the chassis.
4. Tune 3TX peak such that two peaks are centred around Marker 1
5. Tune 1TX and 4TX such that the pass band (S21) and return loss (S11) are within acceptable limits. Acceptable
limits will vary across the band. As a guide a pass band loss of approximately 3.4dB and return loss of greater than
18dB are considered acceptable.
6. Tune notch trimmer, TP2, such that Marker 2 is in the centre of the notch. You should target at least 60dB of notch
rejection; however, this will increase to approximately 65dB of rejection when the Rx side is tuned.
7.3.2.2 To Calibrate the Rx Side
1. Ensure the source power from the VNA is less than -15dBm for the Rx port to avoid overloading the LNA on the
duplexer printed circuit board.
2. Connect Port 1 to the Antenna Port, connect Port 2 to Rx Port, connect a 50ohm load to TX Port, Connect +5V.
3. Ensure Rx is completely detuned.
4. Tune 2RX to peak at Marker 2.
5. Tune 3RX to peak such that two peaks are centred around Marker 2.
6. Tune 1RX and 4RX such that the pass band (S21) and return loss (S11) are within acceptable limits. Acceptable
limits will vary across the band. As a guide a pass band gain of approximately 10.5dB and return loss of greater than
15dB are considered acceptable.
7. Tune notch trimmer, TP1, such that Marker 1 is in the centre of notch. You should target at least 50dB of notch
rejection. In addition to the gain of 10.5 the total notch rejection relative to the pass band will be greater than 60dB.
8. Recheck TX Tuning to ensure that the Rx hasn’t upset the match and to confirm that the TX notch depth is approx.
65 dB or greater. If the TX match has changed it is likely that 1TX will need to be re-tuned to correct for the Rx
interaction.
9. Once both channels have been re-tuned then reconnect the four duplexer coax cables to the RF board, reconnect
+5V and assemble the chassis. Ensure the two O-ring seals are fitted and the main radio seal around the
perimeter of the unit is seated firmly in its channel on the digital side of the clam shell. Once the radio is
reassembled proceed with power calibration as per Section 6.5.
7.4 RSSI CALIBRATION
The RSSI and AGC control voltage are in linear relationship, as shown in formula 1.
RSSI = A x Vagc + B (1)
Where A represents the slope of the curve and B is the offset.
To find out A and B value we need two points (RSSI1, Vagc1) and (RSSI2, Vagc2), which are obtained by applying -50dBm
and -90dbm signal at the receiver and recording the AGC voltage respectively.
Error! Reference source not found. shows the RSSI Calibration page (Calibration > RSSI Calibration. The RSSI calibration
can be easily achieved by following the instruction step by step. Below is the summary of the procedure.
1. Connect signal generator via a 30dB attenuator to Channel 1 receiver.
2. Set signal generator level so that -50dBm can be measured at the receiver input. Choose un-modulated carrier for
the input signal.
3. Select Rx1 in the CCMS page.
4. Select -50dBm in the CCMS page.
5. Click Read in the CCMS page.
6. Set signal generator level so that -90dBm can be measured at the receiver input.
7. Select -90dBm in the CCMS page.