Crescend Technologies UHFP10XXUL1 AMPLIFIER User Manual P10 UHF Manual for FCC O
Crescend Technologies LLC AMPLIFIER P10 UHF Manual for FCC O
Users Manual
Copyright Crescend Technologies Rev O
INSTALLATION AND SERVICE
MANUAL
CONTINUOUS DUTY
UHF POWER AMPLIFIER
July 3, 2008
Crescend Technologies
920 E. State Parkway
Schaumburg, IL 60173
Tel: 847 908 5400
Fax: 847 908 5408
Email: sales@CrescendTech.com
Web Site: www.CrescendTech.com
Copyright Crescend Technologies 2 Rev O
GENERAL DESCRIPTION
1.1. INTRODUCTION
This manual contains information and procedures for installation, operation, and general
maintenance of Crescend’s UHF Continuous Duty Power Amplifier.
1.2. PRODUCT DESCRIPTION
The Crescend Technologies UHF RF power amplifiers are designed for trunking and conventional
repeater applications. Rack mountable and designed to accept a range of input powers for a given
rated output power, the amplifier covers a broad range of frequencies. Closed loop power control
is used to maintain a constant output power under varying voltage, signal input, frequency and
output load conditions. Several design features work to protect the amplifier under adverse
conditions.
The amplifier front panel includes status LED indicators for DC and Alarm conditions. RF Input,
RF Output, DC, summary alarm and power cutback connections are found on the back of the
amplifier. A fan is used to cool the amplifier.
Table 1-1. Amplifier Functional Specifications
Frequency Range: 403 – 470 MHz
Operating Voltage: +13.8 ±0.7 Vdc
Current Consumption: See Table 1-2
Duty Cycle: 100%
Power Input: See Table 1-2 (Range Set at Factory)
Power Output (Single Carrier Operation): See Table 1-2 (Set at Factory)
Power Output Change (Relatively set up value) + 1 dB (Maximum)
Input Return Loss: -10 dB (Maximum)
Spurious & Harmonics: - 65 dBc (Maximum)
Input/Output Impedance: 50 Ohms (Nominal)
Load VSWR Tolerance: VSWR Protected above 3.5:1 (Nominal)
Input/Output Connector: Type N Female
Vertical Mounting: 7.0 in
Horizontal Mounting: 19.0 in
Weight: 10 lbs (4.6 kg) (Nominal)
Cooling Method: Fan Forced Air Over Heat Sink
Operating Temp. Range: -30°C to +60 °C
Storage & Transport: -40 °C to +70 °C
Humidity: 80% at +40 °C (Non-Condensing)
Altitude: 10,000 Feet (Maximum)
Front Panel Display: INDICATORS
DC ON (Green), LOW OUTPUT (Red), HIGH
VSWR (Red), OVER TEMP (Red)
Alarm and Control Pins:
SUMMARY ALARM
Summary of Low Output, High VSWR, Over Temp
Alarms
CONTROLS
CTRL(Partial Power Cutback)
SH/D (External Power Control)
Copyright Crescend Technologies 3 Rev O
Table 1-2. Input/Output Power, Current, Spurious and Harmonics
Input Power Range (W) Rated Output
Power (W) Typ Current
(A) Max Current
(A)
0.1-0.2
0.2-0.5
0.5-1
1-2
2-5
5-10
10-20
20-50
80 (P8)
100 (P10) 18
21 23
26
NOTES: Manufacturer’s Rated Output Power of this Equipment is for Single Carrier
Operation.
All specifications above apply at +13.8 ± 0.1 VDC operating voltage,
ambient temperature of 25°C ± 5°C.
Copyright Crescend Technologies 4 Rev O
2. INSTALLATION
2.1. INTRODUCTION
This section contains installation recommendations, unpacking, inspection, and installation
instructions for the amplifier. Carefully read all the material in this section prior to equipment
unpacking or installation. Also read and review the operating procedures in Section 3 prior to
installing the equipment. It is important that the licensee perform these tasks correctly and in good
faith. If applicable, carefully read Parts 73 and 74 of the Federal Communications Commission
(FCC) rules to determine how they apply to your installation.
2.2. ELECTRICAL SERVICE RECOMMENDATIONS
Crescend Technologies recommends that proper AC line conditioning and surge suppression be
provided on the primary AC input to the +13.8 VDC power source. All electrical service should be
installed in accordance with the National Electrical Code, any applicable state or local codes, and
good engineering practice. Special consideration should be given to lightning protection of all
systems in view of the vulnerability of most transmitter sites to lightning. Lightning arrestors are
recommended in the service entrance. Straight, short ground runs are recommended. The
electrical service must be well grounded. Each amplifier should have its own circuit breaker.
2.3. UNPACKING AND INSPECTION
This equipment has been operated, tested and calibrated at the factory. Only in the event of
severe mechanical shocks or other mistreatment should any substantial readjustment be required.
Carefully open the container(s) and remove the amplifier module(s). Retain all packing material
that can be reassembled in the event that the unit must be returned to the factory.
CAUTION: Exercise care in handling equipment during inspection to
prevent damage caused by rough or careless handling.
Visually inspect the amplifier module for damage that may have occurred during shipment. Check
for evidence of water damage, bent or warped chassis, loose screws or nuts, or extraneous
packing material in the connector or fans. Inspect the rear panel connector for bent connector pins.
If the equipment is damaged, a claim should be filed with the carrier once the extent of any
damage is assessed. We cannot stress too strongly the importance of IMMEDIATE careful
inspection of the equipment and the subsequent IMMEDIATE filing of the necessary claims
against the carrier if necessary. If possible, inspect the equipment in the presence of the delivery
person. If the equipment is damaged, the carrier is your first area of recourse. If the equipment is
damaged and must be returned to the factory, write or phone for a return authorization. Crescend
may not accept returns without a return authorization. Claims for loss or damage may not be
withheld from any payment to Crescend, nor may any payment due be withheld pending the
outcome thereof. WE CANNOT GUARANTEE THE FREIGHT CARRIER’S PERFORMANCE.
2.4. INSTALLATION INSTRUCTIONS
This amplifier is designed for installation in a rack that permits access to the rear of the rack for
connection of DC power, RF, and monitor/control cables. The amplifier must have a minimum of 3
inches of open space to the rear to allow adequate ventilation.
To install the amplifier proceed as follows:
1. Install amplifier in equipment rack and secure in place.
2. Connect a 50 ohm antenna cable and load to the RF OUT connector on rear of amplifier.
3. Connect the transceiver/exciter output to RF IN connector on rear of amplifier.
4. If monitoring of PA is desired, connect alarm cable to “ALARM” pin on rear of amplifier
module. See section 2.5 for more details.
5. If limited output power control of PA is desired, connect control cable or appropriate
resistor to “SH/D” pin on rear of amplifier module. See section 2.5 for more details.
Copyright Crescend Technologies 5 Rev O
6. If remote output power cutback of PA is desired, connect control cable to “CTRL” pin on
rear of amplifier module. See section 2.5 for more details.
7. Measure primary DC input voltage. DC input voltage should be +13.8 +/- 0.1VDC. Turn
off DC voltage.
WARNING: Turn off external primary DC power before connecting DC power cables.
8. Connect positive primary power wire (+13.8VDC) to terminal marked +13.8VDC and
negative primary power wire to GND terminal on rear of amplifier.
9. Check your work before applying DC voltage to the system. Make certain all connections
are tight and the DC wires are going to the correct terminals.
10. Refer to Section 3 for initial start-up procedures.
NOTE:
1. Make sure power supply DC is well filtered and well behaved with minimal voltage
overshoot.
2. Keep DC wires as short as possible to minimize inductance induced voltage transients.
3. Size DC Wires properly to handle the load current to minimize voltage drop.
2.5. AMPLIFIER SUMMARY ALARM AND POWER CUTBACK CONTROL
The summary alarm and cutback control connections are made through separate filtered
feedthrough connectors on the back of the amplifier.
Table 2-1. Summary Alarm and Cutback Control Connections
PIN FUNCTION DESCRIPTION CONDITION APPROPRIATE
LOAD
Alarm: < 0.8 VDC
Normal Operation: > 9 VDC
(up to Vcc)
> 10 kOhm,
< 100pF
ALARM Summary
Alarm
Indicates when:
1. The output power is
low, or
2. VSWR cutback is
activated, or
3. Thermal cutback is
activated
Alarm: < 0.8 VDC
Normal Operation: 4 - 5 VDC
1.8 kOhm
between pin and
ground,
<500 pF
(TTL
compatible)
Normal Operation – pin not
connected.
CTRL Partial
Power
Cutback
Used as a simple means
of cutting back output
power by a fixed amount
(0.7-1.4 dB).
Cutback Mode – pin pulled to
ground. The output power
reduces by approximately
1dB.
<10 Ohm,
< 100pF
Normal Operation – pin not
connected.
SH/D External
Power
Control
It is possible to reduce
the output power
continuously by up to 4
dB by connecting a
resistor between this pin
and ground.
Power Control Mode – pin
pulled to ground through
resistor.
Resistor value
0-50 kOhm,
<100 pF
Copyright Crescend Technologies 6 Rev O
3. GENERAL OPERATING INFORMATION
3.1. INTRODUCTION
This section contains operating instructions for the amplifier.
3.2. STATUS INDICATORS
The function of the amplifier status indicators and is described in Table 3-1.
Table 3-1. Amplifier Status Indicators
STATUS LED FUNCTION
DC ON
Green LED. Illumination indicates DC Power has been applied.
LOW OUTPUT
Red LED. Activates when the output power drops to approximately
70-80% of set output power.
HIGH VSWR
Red LED. Activates when load VSWR exceeds approximately
3.5:1.
HIGH TEMP
Red LED. Activates when the amplifier exceeds a safe operating
temperature.
3.3. INITIAL STARTUP
To perform the initial start-up, proceed as follows:
Check to ensure that all input and output cables are properly connected and tightened.
Note: Use high quality coaxial cable and connectors. Properly install and solder all connectors for
reliability.
CAUTION: Before applying power, make sure that the input and output of the
amplifier are properly terminated in 50 ohms. Do not operate the
amplifier without a load attached. Refer to Table 1-2 for input
power requirements. Excessive input power will damage the
amplifier.
NOTE:
The output coaxial cable between the amplifier and the antenna
must be 50 ohm coaxial cable.
2. Apply DC power to the amplifier. Verify that the power supply measures 13.8 ± 0.1VDC. The fan
will come on immediately for a few seconds and then turn off.
3. Visually check the indicators on each amplifier module, and verify the following:
a. The DC PWR ON indicator (green) should be on.
b. All ALARM LED indicators (red) should be off.
4. Turn on external exciter/transceiver and apply RF input signal. The fan should turn on after
approximately 3 seconds.
Copyright Crescend Technologies 7 Rev O
Warning: Be sure that the signal frequency is in the range 403 – 470 MHz!
5. Turn off RF input signal. The fan should continue running, but turn off after approximately 6-12
seconds.
4. PRINCIPLES OF OPERATION
4.1. INTRODUCTION
This section contains principles of operation of the RF Power Amplifier.
4.2. RF INPUT SIGNAL
The amplifiers are set at the factory to work over different input power ranges. The available
range of inputs ranges may be found in Table 1-2.
4.3. RF OUTPUT LOAD
The load impedance should be as good as possible (VSWR <1.2:1) in the working band for good
power transfer to the load and maximum amplifier efficiency.
4.4. FUNCTIONAL DESCRIPTION
The amplifier is a single channel CW amplifier that operates over the UHF frequency range. The
amplifier specifications are listed in Tables 1-1 and 1-2.
4.4.1. MAIN RF PATH
The typical main RF path consists of an input attenuator, driver, splitter, final stage(s), combiner,
rf detectors and harmonic filter. The circuitry becomes active upon the sensing of rf input power.
This occurs when rf input reaches approximately 3 dB below the low end of the input power
range. This keeps standby current at a minimum (< 20 mA) when rf input is not present (or is
below the turn on level).
4.4.2. LOOP CONTROL
The loop control circuitry includes circuitry to works to maintain a constant output power versus
variations in DC voltage, rf input power, frequency and load. A coupled detector at the output
monitors the final RF output level and generates a DC voltage proportional to the RF output
level. This voltage is fed back to the controller. The circuitry compares this voltage to a
reference voltage and varies the gain of the amplifier to maintain a constant output.
4.4.3. VSWR PROTECTION
Reflected power is detected at the output of the amplifier and compared to forward power.
When reflected power reaches an equivalent VSWR of approximately 3.5:1, the amplifier output
is reduced to protect the finals and the front panel HIGH VSWR LED activates. The higher the
load VSWR, the more the output power is reduced.
4.4.4. THERMAL PROTECTION
The heat sink temperature is monitored with a thermostat. When the heat sink temperature
reaches an unsafe level, the output power of the amplifier is reduced by approximately 50%.
This keeps the channel on the air while still providing some short term protection until the
customer can address the underlying cooling issue.
4.5. AMPLIFIER COOLING
The amplifier is cooled with forced air over a large heat sink. It is important to keep a minimum
clearance of 3 inches behind the amplifier and allow the coolest air possible to circulate through
the fan.
Copyright Crescend Technologies 8 Rev O
5. MAINTENANCE
5.1. INTRODUCTION
This section contains periodic maintenance and performance test information for the amplifier.
NOTE:
Check your sales order and equipment warranty before attempting to service or
repair the unit. Do not break the seals on equipment under warranty or the warranty
will be null and void. Do not return equipment for warranty or repair service until
proper shipping instructions are received from the factory.
5.2. PERIODIC MAINTENANCE
Periodic maintenance requirements are listed in Table 5-1. Table 5-1 also lists the intervals at
which the tasks should be performed.
WARNING: Wear proper eye protection to avoid eye injury when using compressed air.
Table 5-1. Periodic Maintenance
TASK INTERVAL ACTION
Clean Air Vents/Check
Fan 30 Days Inspect and clean per paragraph 5-3.
Verify fan is working properly.
Inspect Cables and
Connectors and General
Site Conditions
6 Months Inspect signal and power cables for
frayed insulation and proper attachment.
Check RF connectors to make sure that
they are tight. Inspect the lightning
protection system and ground at the site.
5.3. CLEANING AIR INLETS/OUTLETS
The air inlets and outlets should be checked every 30 days and cleaned if necessary. If the
equipment is operated in a severe dust environment, it should be checked and cleaned more
often. If dust and dirt are allowed to accumulate, the cooling efficiency will be diminished. Using
either compressed air or a brush with soft bristles, loosen and remove accumulated dust and dirt
from the air inlet panels.
Check that the fan is running smoothly. A slow running or noisy fan may indicate an imminent fan
failure. Replace immediately with a similar to insure long term reliability. Heat is one of the
biggest factors in reducing the reliability of your amplifier. Make sure the fan has access to cool
and clean airflow within the rack.
Copyright Crescend Technologies 9 Rev O
5.4. TEST EQUIPMENT REQUIRED FOR TEST
Test equipment required to test the amplifier performance is listed in Table 5-2. Equivalent test
equipment may be substituted for any item.
NOTE: All RF test equipment must be calibrated to 0.05 dB resolution. Any deviation from the
nominal attenuation must be accounted for and factored into all output readings.
Table 5-2. Test Equipment Required (or equivalent)
EQUIPMENT MANUFACTURER MODEL
Signal Generator (1) H.P. 8657B
30 dB Attenuator, 200 Watt (1) Tenuline 8322
DC power supply (1) H.P 6673A
Spectrum Analyzer (1) H.P. 8560E
Power Meter (1) HP E4418A
Power Meter (1) HP E4419A
Power Sensor (3) HP 8481A
Pad (3) Mini-Circuits NAT-20
Coupler (2) Narda 3020A
Coupler Load (1)
Lab Amplifier (1) AR 30W1000M7
5.5. PERFORMANCE TEST
Performance testing may be conducted to ensure that the amplifier system meets the operational
specifications listed in Tables 1-2 and 1-3. The test equipment required to perform the testing is
listed in Table 5-2 and the test setup is shown in Figure 5-1.
Figure 5-1. Amplifier Test Setup Diagram
Signal
Generator Lab
Amplifier Coupler
UUT Coupler Attenuator
30 dB Spectrum
Analyzer
Power
Supply
20
dB 20
dB 20
dB
Watt Meter
Watt Meter
Lo
ad
S
e
n
s
e
S
e
n
s
e
S
e
n
s
e
Copyright Crescend Technologies 10 Rev O
6. TROUBLESHOOTING
6.1. INTRODUCTION
This section contains a list of potential problems and suggested actions to be taken. If the
suggested corrective action does not eliminate the problem, please contact your Crescend factory
for further instructions.
NOTE: Check your sales order and equipment warranty before attempting to service or
repair the unit. Do not break the seals on equipment under warranty or the warranty will
be null and void. Do not return equipment for warranty or repair service until proper
shipping instructions are received from the factory.
6.2. TROUBLESHOOTING
Refer to Table 6-1 for troubleshooting suggestions. It has been found that in some cases it may
be necessary to power cycle an amplifier (turn DC power off and back on without RF applied) to
clear an alarm. Table 6-1. Troubleshooting
INDICATOR LED STATUS OUTPUT POWER STATUS POSSIBLE CAUSE SUGGESTED ACTIONS
Unlit No power No voltage at unit 1. Check power supply voltage DC PWR ON
(Green) On Set power Normal operation 1. No action required
Frequency is out of
range 1. Check frequency
The input power is
below the low end of
the rated input range
1. Check input power
Power supply voltage
is too low 1. Check power supply voltage
at amplifier DC connector
during key-up
On (all other
alarm LEDs
off)
Problem inside
amplifier 1. Send the unit back to factory
LOW
OUTPUT
(Red)
On (together
with HIGH
VSWR alarm
LED)
Less than set power
Output load VSWR is
much above 3.5:1 1. Turn off amplifier (or remove
RF input)
2. Check output connections
and cables for integrity and
tightness
3. Check antenna, combiner,
etc. for proper return loss
HIGH VSWR
(Red) On Less than set power Output load VSWR is
above 3.5:1 1. Turn off amplifier (or remove
RF input)
2. Check output connections
and cables for integrity and
tightness
3. Check antenna, combiner,
etc. for proper return loss
Fan is not rotating 1. Check if +13 VDC is present
on the FAN feedthrough pin
when rf input present (after
3 sec turn on delay)
2. Check if anything is
physically stopping rotation
3. If fan has failed, replace fan
with same or similar fan
OVER TEMP
(Red) On Less than set power
Power supply voltage
is too low causing
insufficient air flow
1. Check power supply voltage
Copyright Crescend Technologies 11 Rev O
Operating
temperature of
amplifier is exceeding
safe level. Note:
When unit cools, LED
turns off and output
returns to rated power
2. Make sure that air access to
front and rear of unit is
unimpeded
3. Verify that air vents are
clear of dust and dirt and
that fan(s) are operating
properly. Replace fan if
necessary
4. Check ambient temperature
(not to exceed spec - see
Table 1-2)
Copyright Crescend Technologies 12 Rev O
6.3. RETURN FOR SERVICE PROCEDURES
When returning products to Crescend, the following procedures will ensure optimum response.
6.3.1. OBTAINING AN RMA
A Return Material Authorization (RMA) number must be obtained prior to returning equipment
to the factory for service. Please contact our Customer Service Department at 800-872-6233
to obtain this number. Failure to obtain this RMA number may result in considerable delays in
receiving repair service.
6.3.2. REPACKAGING FOR SHIPMENT
To ensure safe shipment of the amplifier, it is recommended to use the packaging designed
for the amplifier. The original packaging material is reusable. If it is not available, contact
Crescend’s Customer Service Department for packing materials and information.