Crescend Technologies C7 SERIES Installation And Service Manual

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INSTALLATION AND SERVICE

MANUAL

C7 SERIES

CONTINUOUS DUTY

POWER AMPLIFIER

Crescend Technologies 140 E. State Parkway Schaumburg, IL 60173

RACK OF C7 AMPLIFIERS

December 20, 2015

Tel: 847 908 5400 Fax: 847 908 5408 Email: sales@CrescendTech.com Web Site: www.CrescendTech.com

TABLE OF CONTENTS

Section 1

Par. No.

1.1 Introduction 4

1.2 Product Description 4

1.3 Functional and Physical Specifications 5

1.4 Equipment Changes 5

2.1 Introduction 8

2.2 Electrical Service Recommendations 8

2.3 Unpacking and Inspection 8

2.4 Installation Instructions 9

2.5 Amplifier Summary Alarm and Power Cutback Control 10

3.1 Introduction 11

3.2 Location of Status Indicators 11

3.3 Initial Start-Up 12

General Description

Section 2

Installation

Section 3

General Operating Information

Page No.

Section 4

Principles of Operation

4.1 Introduction 13

4.2 RF Input Signal 13

4.3 RF Output Load 13

4.4 Functional Description 13

4.4.1 Main RF Path 13

4.4.2 Loop Control 13

4.4.3 VSWR Protection 13

4.4.4 Thermal Protection 13

4.5 Amplifier Cooling 13

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TABLE OF CONTENTS (Continued)

Section 5

Par. No.

5.1 Introduction 14

5.2 Periodic Maintenance 14

5.3 Cleaning Air Inlets/Outlets 14

5.4 Test Equipment Required for Test 15

5.5 Performance Test 15

6.1 Introduction 16

6.2 Troubleshooting 16

6.3 Return for Service Procedure 17

6.3.1 Obtaining an RMA 17

6.3.2 Repackaging for Shipment 17

Maintenance

Section 6

Troubleshooting

Page No.

Figure

1-1 C7 Series Single Amplifier, Front View 4 1-2 C7 Series Single Amplifier, Rear View 5 2-1 FPR-5 Rack, Front Right View 9 2-2 C7 Series Amplifiers in Rack, Rear View 10 3-1 C7 Series Status Indicators, Front Panel 11 5-1 Amplifier Test Setup diagram 15

List of Illustrations

List of Tables

Table

1-1 1-2 Frequency Ranges, Input/Output Power, Current,

2-1 Summary Alarm Connection 10 3-1 C7 Series Amplifier Status Indicators 11 5-1 Periodic Maintenance 14 5-2 Test Equipment Required 15 6-1 Troubleshooting 16

C7 Series Amplifier Functional Specifications 6

Spurious and Harmonics

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1. GENERAL DESCRIPTION

1.1. INTRODUCTION

This manual contains information and procedures for installation, operation, and maintenance of Crescend’s C7 Series Continuous Duty Power Amplifier. The manual is organized into six sections as follows:

Section 1. General Description Section 2. Installation Section 3. Operating Instructions Section 4. Principles of Operation Section 5. Maintenance Section 6. Troubleshooting

1.2. PRODUCT DESCRIPTION

The Crescend Technologies C7 Series of 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, each amplifier covers a broad range of frequencies without retuning. 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.

Having the same features as our popular Crescend C5 models, the design of the C7 amplifiers allows for up to 5 amplifiers in 4U of rack space. Designed to be fully modular and space efficient, the 5-pack series also provides continuous duty operation. Rack FPR-5 sold separately.

The C7 front panel (Figure 1-1) includes status LED indicators for DC and Alarm conditions. RF Input, RF Output, DC and summary alarm connections are found on the back of the amplifier (Figure 1-2).

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Figure 1-1. C7 Series Single Amplifier, Front View

Figure 1-2. C7 Series Single Amplifier, Rear View

1.3. FUNCTIONAL AND PHYSICAL SPECIFICATIONS

Functional and physical specifications for the C7 Series amplifiers are listed in Tables 1-1 and 1-2.

1.4. EQUIPMENT CHANGES

Crescend Technologies, Inc. reserves the right to make minor changes without notice, including, but not necessarily limited to, component substitution and circuitry changes. Such changes may or may not be incorporated in this manual, although it is our intention to keep each manual as up-to-date as possible. To that end, we ask that you, our customer, share information with us acquired in field situations, which might be of assistance to another user.

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Table 1-1. C7 Series Amplifier Functional Specifications

Frequency Range: See Table 1-2 (Range Set at Factory) 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 (Range Set at Factory) Input Return Loss: -10 dB (Maximum) Spurious & Harmonics: See Table 1-2 Input/Output Impedance: 50 Ohms (Nominal) Load VSWR Tolerance: VSWR Protected above 2.5:1 (Nominal) Input/Output Connector: Type N Female Vertical Mounting: 7.0 in Horizontal Mounting: 3.4 in Depth: 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)

INDICATORS

Front Panel Display:

DC ON (Green), LOW OUTPUT (Red), HIGH VSWR (Red), OVER TEMP (Red)

SUMMARY ALARM

Alarm and Pins:

Summary of Low Output, High VSWR and Over Temp Alarms

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Table 1-2. Frequency Ranges, Input/Output Power, Current, Spurious and Harmonics

Frequency

Range (MHz)

30-36 (AA) 36-42 (AB) 42-50 (AC)

Input Power

Range (W)

2-5

5-10 10-20 20-50

Rated Output

Power (W)

100 (P10) 20 23 <

Typ

Current

(A)

Max

Current

(A)

Spurious and

Harmonics

(dBc)

-65

0.1-0.2

0.2-0.5

0.5-1

136-174 (DE)

1-2

50 (P5) 11 12 <

-70

2-5

5-10 10-20

0.1-0.2

0.2-0.5 136-144 (DA) 136-174 (DB) 152-162 (EA) 162-174 (EB)

0.5-1 1-2 2-5

5-10

100 (P10) 110 (P11) 150 (P15)

18 22 26

23 25 28

-65 <-65 <-67

10-20 20-50

0.1-0.2

0.2-0.5

0.5-1

360-400 (UXL)

450-512 (UH)

1-2 2-5

50 (P5)

100 (P10)

11 21

12 25

<-70 <-70

5-10 10-20 20-50

0.1-0.2

0.2-0.5

0.5-1

764-870 (JK)

1-2 2-5

80 (P8) 20 24 <-70

5-10 10-20 20-50

0.1-0.2

0.2-0.5

0.5-1

928-942 (L)

1-2 2-5

80 (P8) 20 24 <-70

5-10 10-20 20-50

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.

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2. INSTALLATION

2.1. INTRODUCTION

This section contains installation recommendations, unpacking, inspection, and installation instructions for the C7 Series of amplifiers. 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 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.

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2.4. INSTALLATION INSTRUCTIONS

The C7 amplifier is designed for installation in a rack (Figures 2-1 and 2-2) that permits access to the rear of the rack for connection of DC power, RF, and monitor cable. The amplifier must have a minimum of 3 inches of open space in front of and behind the rear fan to allow adequate ventilation.

To install the amplifier proceed as follows:

1. Install FPR-5 subrack into a 19 inch equipment rack using the front and rear mounting points

2. Install amplifier in subrack and secure in place with two thumbscrews on front panel.

3. Connect a 50 ohm antenna cable and load to the RF OUT connector on rear of amplifier.

4. Connect the transceiver/exciter output to RF IN connector on rear of amplifier.

5. If monitoring of PA is desired, connect alarm cable to “ALARM” pin on rear of amplifier module. See section 2.5 for more details.

6. 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.

7. Connect positive primary power wire (+13.8VDC) to terminal marked +13.8VDC and negative primary power wire to GND terminal on rear of amplifier.

8. 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.

9. 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.

Figure 2-1. FPR-5 Rack, Front Right View

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Figure 2-2. C7 Series Amplifiers in Rack, Rear View

2.5. AMPLIFIER SUMMARY ALARM

The summary alarm connections is made through a filtered feedthrough connector on the rear of the amplifier (see Table 2-1).

Table 2-1. Summary Alarm Connection

PIN FUNCTION DESCRIPTION CONDITION

Alarm: < 1 VDC Normal Operation: > 8 VDC (up to Vcc)

Alarm: < 1 VDC Normal Operation: 4 - 5 VDC

ALARM

Summary Alarm

Indicates when:

1. The output power is low, or

2. VSWR cutback is activated, or

1.8 kOhm between pin and ground,

3. Thermal cutback is activated

<500 pF (TTL compatible)

APPROPRIATE

LOAD

> 10 kOhm, < 100pF

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3. GENERAL OPERATING INFORMATION

3.1. INTRODUCTION

This section contains operating instructions for the C7 amplifier.

3.2. LOCATION OF STATUS INDICATORS

The location and function of the C7 amplifier status indicators and is shown in Figure 3-1 and described in detail in Table 3-1.

Figure 3-1. C7 Series Status Indicators, Front Panel

Table 3-1. C7 Series Amplifier Status Indicators

STATUS LED FUNCTION

DC ON

LOW OUTPUT

Green LED. Illumination indicates DC Power has been applied.

Red LED. Activates when the output power drops to approximately 80-85% of set output power.

HIGH VSWR

Red LED. Activates when load VSWR exceeds approximately

2.5:1.

HIGH TEMP

Red LED. Activates when the amplifier exceeds a safe operating temperature.

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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.

amplifier without a load attached.

Refer to Table 1-2 for input

Do not operate the

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.

5.Turn off RF input signal. The fan should continue running, but turn off after approximately 6-8 seconds.

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4.1. INTRODUCTION

This section contains principles of operation of the C7 Series of RF Power Amplifiers.

4.2. RF INPUT SIGNAL

The amplifiers are set at the factory to work over different input power ranges. The available range of inputs for different frequency 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 in various frequency bands from 30 MHz to 942 MHz. 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, rf amplifier , 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.

PRINCIPLES OF OPERATION

4.4.2. LOOP CONTROL

The loop control circuitry 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 2.5:1, 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. The fan draws in ambient air from the front. It is important to maintain a minimum clearance of 3 inches in front of and behind the amplifier to allow for best cooling of the amplifier.

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5. MAINTENANCE

5.1. INTRODUCTION

This section contains periodic maintenance and performance test information for the C7 Series. It also contains a list of test equipment required to perform various tests.

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 Inspect Cables and Connectors and General Site Conditions

30 Days Inspect and clean per paragraph 5-3.

Verify fan is working properly.

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.

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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 1-1 and 1-2. The test equipment required to perform the testing is listed in Table 5-2 and the test setup is shown in Figure 5-1.

Watt Meter Watt Meter

20 dB

S e n s e

Lo ad

30 dB

Signal

Generator

Lab

Amplifier

Coupler UUT Coupler Attenuator

Power

Supply

Figure 5-1. Amplifier Test Setup Diagram

Spectrum

Analyzer

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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

(Green) LOW

OUTPUT (Red)

HIGH VSWR (Red)

OVER TEMP (Red)

Off No power No voltage at unit 1. Check power supply voltageDC ON On Set power Normal operation 1. No action required On (all other alarm LEDs off)

On (together with HIGH VSWR alarm LED)

On Less than set power Output load VSWR is

On Less than set power

Less than set power

Frequency is out of range

The input power is below the low end of the rated input range

Power supply voltage is too low

Problem inside amplifier

Output load VSWR is much above 2.5:1

above 2.5:1

Fan is not rotating 1. Check if +13 VDC is present

Power supply voltage is too low causing insufficient air flow

Operating temperature of amplifier is exceeding safe level. Note: When unit cools, LED turns off and output returns to rated power

1. Check frequency

1. Check input power

1. Check power supply voltage at amplifier DC connector during key-up

1. Send the unit back to factory

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

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

across the FAN leads

2. Check if anything is physically stopping rotation

3. If fan has failed, replace fan with same or similar fan

1. Check power supply voltage

2. Make sure that air access to front and rear of unit is unimpeded (3 inches min)

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)

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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.

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Crescend Technologies C7 SERIES Installation And Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual