User's Manual

Page 8 R
F
Technology
2 CIRCUIT DESCRIPTION 3. Field alignment procedure
Equipmen
t
Type Key Specifications
Power Supply 13.8Vdc, 25A
RF Source 2 Wat
t
(eg. Eclipse2 Basestation)
RF Load
/
Attenuator
50 Ω , 100W, SWR<1.2:1
RF Powe
r
Meter
eg. calibrated detecto
r
and
voltmeter
Short Circuit
N-type, 0 Ω , 100W Short
Table 2: Standard test equipment for the IP
•
PA500BH Power Amplifier
2.6 RF Output Indicator
The forward power voltage is compared with a pre-set dc reference voltage by U23. The
output of U23 is used to turn on the RFO LED. The reference voltage is set to turn on
the led when output power is between 1-120 Watts.
2.7 Over Temperature Protection
Thermistors RT1 and RT2 are mounted to the case of RF module U15 and U16. If
either module case temperature rises above 85 Celsius the resistance of RT1 or RT2
increases and Q25 or Q26 is turned ON.
This causes the TEMP LED to come on and also reduces the dc reference voltage to the
output power error amplifier U22. The output power will then be reduced by the
amplifiers ALC circuits and the modules are kept within safe operating limits.
3 Field Alignment Procedures
3.1 Output Power Level and Reverse Power Limit
1. Set the unit up on a bench with the standard test equipment listed in table 2.
2. Set
*
RV1 fully counter-clockwise and
*
RV2 fully clockwise.
3. Set the Eclipse2 basestation to the desired operating frequency.
4. Adjust RV1 for the desired output power.
5. Disconnect power and swap load with the N-type short.
6. Set
*
RV2 both fully counter-clockwise.
7. Apply Power and adjust
*
RV2 for maximum reverse power (Typically 25Watts).
3.2 Tuning Procedure
No further Tuning or Adjustment is required.
*
(Note: RV1 and RV2 may be replaced with fixed value resistors R279, R153, R154, R155 and R156)
E2-IP-PA 500BH