RF-103A 1KW LINEAR POWER AMPLIFIER

TECHNICAL SPECIFICATIONS

OPERATING INSTRUCTIONS

LOCAL MANUAL OPERATION

(Local Operation of the RF-103A with an Exciter that does not have "Channel Control Provisions")

1. Set FILAMENT switch at ON and FREQUENCY MC switch to the band that includes the exciter's operating frequency. Observe that the FILAMENT indicator is lit.
2. If an antenna coupler is being used, tune it for minimum VSWR according to the instruction manual supplied with it.
3. Refer to table 1 and check for a previously recorded value for the operating frequency. If a value has been recorded, adjust the Tuning Reference Meter with the TUNING switch to the listed value. If no value is listed, then set the Tuning Reference Meter to the 50 mark.
4. Set PLATE switch at ON. Observe that the PLATE indicator is lit. Set METER SELECTOR switch at PLATE VOLTS and check that the meter is indicating in the green area. Set METER SELECTOR switch at OUTPUT.
5. Set the exciter for either AM (no modulation) or CW (with reduced drive) for a driver level of 20 to 30 watts. Key the exciter and with the TUNING switch adjust the RF-103 for maximum output power (approximately 370 watts).

6. At the exciter, adjust the RF drive until the RF-103 indicates 1000 watts in the CW mode or on voice peaks (SSB mode).
7. Unkey the exciter. The system is now ready for normal operation. Record the Tuning Reference Meter indication for future reference.

LOCAL AUTOMATIC OPERATION

(Local Operation of the RF-103A with an Exciter that has Channel Control Provisions)

1. Open the front door and check that the Local/Remote switch on the Junction/Program Board (inside front door) is set at LOCAL. Close the front door.
2. Set FILAMENT switch at ON and FREQUENCY MC switch at CHANNEL.
3. After a one minute warm-up period, set PLATE switch ON.

4. Select the desired channel with the CHANNEL SELECTOR switch. Observe that the proper channel indicator is illuminated.
5. Energize the exciter. Operation can now be performed by keying the exciter.

GENERAL DESCRIPTION

The HARRIS RF-103A is a 1KW Linear Power Amplifier designed for use in radio communication systems. It provides high power output across a specified frequency range. The unit features various controls and indicators on its front panel for operation and monitoring.

Operating Controls and Indicators

The front panel of the RF-103A includes:

• MULTIMETER
• TUNING REFERENCE METER
• CHANNEL LIGHTS
• FILAMENT SWITCH & INDICATOR
• PLATE SWITCH & INDICATOR
• METER SELECTOR SWITCH
• TUNING SWITCH
• FREQUENCY MC SWITCH
• CHANNEL SELECTOR SWITCH
• OPERATE LIGHT

The interior of the front door reveals:

• CHANNEL VS FREQUENCY PROGRAM CONNECTIONS
• LOCAL/REMOTE SWITCH
• FUSE F1

SECTION 3 INSTALLATION

3.1 GENERAL

This section provides information for proper installation of the RF-103, including site selection, system connections, and programming/checkout procedures.

3.2 SITE SELECTION

The RF-103 can be installed in any location within 100 cable feet (30.4 meters) of the exciter and 200 cable feet (60.8 meters) of the antenna coupler or antenna. A minimum of four inches (0.15 meters) of clearance is required behind the unit for exhaust airflow.

3.3 UNPACKING AND INSPECTION

Exercise care during unpacking to prevent injury or damage. Inspect the unit for any damage upon removal from the shipping container. Retain packing materials and the container for claims. Verify received items against the shipping list and notify the Sales Department of any discrepancies.

3.4 TUBE V1 INSTALLATION

The power amplifier tube (V1), chimney, and plate cap assembly are shipped separately and require installation. The procedure involves:

1. Unpacking the tube, chimney, plate cap assembly, and plastic bar.
2. Placing the plastic bar over the tube's plate pin and lowering the chimney over the tube.
3. Lowering the tube and chimney into the tube socket, aligning pins, and pressing down to connect.
4. Seating the chimney in the clamp and tightening it.
5. Placing the plate cap on the plate pin and tightening the set screw.
6. Connecting the braided strap of the plate cap assembly to capacitor C29, following instructions on the heat shield (PM-0473A). A caution is noted regarding excessive torque potentially snapping the lug from the capacitor.

3.5 CONNECTIONS

The RF-103 Power Amplifier must be interconnected with associated equipment. This includes AC primary power, RF power, and control connections (keyline, interlocks, grounds, channel control). Refer to exciter and antenna coupler manuals for specific inter-unit connections. The following paragraphs detail general information and requirements.

3.5.1 PRIMARY AC POWER CONNECTIONS

A separate service line from the main service box is recommended due to the unit's high power requirements. The line should be free from other services and capable of supplying 3.2 kVA with good regulation. AC power is supplied via J25 on the rear panel. A power cord with a mating connector for J25 is supplied, suitable for 115V or 230V operation. Power cord color functions are specified:

• For 105V/130V Operation: Black (AC Line High), White (AC Line Low), Green (Source Ground).
• For 210V/260V Operation: Black (AC Line High), White (AC Line High), Green (Common).

Power switching can be remotely controlled by the RF-1206 Remote ON/OFF Kit. Plugs P1 and P2 are typically wired for 110-120 volt operation; refer to figure 3.3 for other voltage adjustments. A ground strap or heavy gauge wire should connect the unit's ground terminal to a separate ground, such as a copper cold water pipe or ground rod.

Outline Dimensions

The unit's dimensions are provided in inches:

• Height: 29-3/4
• Width: 20-5/8
• Depth: 26-3/16 (rear view depth 20-5/8)
• Air intake is located below the unit.
• Air exhaust is at the rear, requiring a minimum 6-inch clearance for cables and exhaust.

3.5.2 RF CONNECTIONS

RF cable connections link the exciter output to the power amplifier and the power amplifier output to the antenna or antenna coupler, using UHF type connectors. For connecting the exciter, RG-58/U coaxial cable is suitable for up to 30 cable feet (7.1 meters); for longer runs, RG-8/U is recommended due to lower loss. Extended cable lengths over 100 feet (30.4 meters) are not recommended. The RF-103 can deliver full output (1000 watts) with 65 watts of exciter drive. An attenuator may be installed on the front right-hand side rail to prevent overdriving the amplifier. The attenuator can be bypassed by connecting the cathode cable directly to the input coaxial relay. The antenna coaxial cable (RG-8/U) up to 100 feet (30.4 meters) connects to J22 on the rear panel.

3.5.3 CONTROL CONNECTIONS

Control connections are made between RF-103 connector J23 (control input from exciter) and the exciter, and J24 (control output to coupler) and the antenna coupler. Most connections use #22 AWG wires, except for antenna coupler power cables which use two #16 AWG wires. Pin assignments for J23 and J24 are detailed in the manual, specifying channel control, keyline interlock, external operate light, and ground connections. The keyline connections can vary based on the equipment used, and interlocking mechanisms prevent the amplifier from being keyed until tuning cycles are complete. A caution is given that equipment may be damaged if used without a keyline interlock, and that utmost care should be taken to ensure the system is not keyed until the amplifier and coupler have completed channeling. The OPERATE light on the front panel can be monitored, or a remotely located 24-volt lamp can be connected.

3.5.4 GROUND CONNECTIONS

Ground connections between units should be made with heavy one-inch wide copper straps or braided wire, keeping leads as short as possible. A ground post on the RF-103 is provided. For separated units, connect each unit's ground post to a good earth ground, such as a copper rod driven into the soil.

3.6 POST INSTALLATION CHECK OUT

After all units are installed and connected, perform the following procedures with all power switches off and tube V1 installed:

1. Set RF-103 switches: FREQUENCY MC switch to 2-2.5 position, CHANNEL SELECTOR switch to neutral (unmarked), FILAMENT switch to OFF, PLATE switch to OFF.
2. Open the front door and set the Local/Remote switch on the Program/Junction Board to LOCAL.
3. Defeat the door interlock switch by pulling out on the switch contact.
4. Remove the top deck heat shield for access.
5. Energize the RF-103 AC primary power. Set FILAMENT switch to ON and observe that the FILAMENT and OPERATE indicators are illuminated. Check that filament V1 is on and both blowers are operating.
6. Rock the TUNING switch and observe that coil L6 rotates in both directions and the Tuning Reference Meter indicates the change. The meter indication should increase up scale, and the coil wiper should move up on the coil windings with the TUNING switch in the INCREASE position.
7. Rotate the FREQUENCY MC switch to each position and observe that the Bandswitch indexes properly to each band. Return the switch to the 2-2.5 position.

Local/Automatic Operation Checkout

Perform the following steps if the RF-103 is to be used with an exciter that has channel control provisions (e.g., RF-220). For exciters without channel control (e.g., RF-301), use the RF-103 CHANNEL SELECT switch in step m to select the channel.

NOTE: If the RF-103 is to be used with both a non-channelizing exciter and a non-channelizing antenna coupler, proceed with step S.

8. Set PLATE switch at ON. Observe the PLATE indicator is illuminated. Set Meter Selector switch at PLATE VOLTS, and check meter indication in the green area. Set Meter Selector switch at PLATE CURRENT.
9. With a jumper wire, short pin 15 of J5 (on Program/Junction Board) to the chassis. The meter should indicate in the green area. Disconnect the jumper wire.
10. Set the RF-103 FREQUENCY MC switch at CHANNEL, PLATE switch at OFF, and the CHANNEL SELECTOR switch at a neutral (unmarked) position. Check if the Program/Junction Board has been programmed to the exciter's channel frequencies. If not, program each channel to its frequency band by connecting the channel pins (E1 through E10) into the frequency band jacks (refer to figure 3.6). If more than five channels are used within one band, connect pin E11 ("M") into an appropriate frequency band jack for an additional five connections per band, totaling ten.

Channel Programming Details

The following table outlines channel programming connections:

(Note: Example channel settings are shown for illustration.)

11. Make sure the Local/Remote switch is set at the Local position on the Program/Junction Board.
12. Refer to the antenna coupler instruction manual and tune it using the exciter drive (RF-103 PLATE switch at OFF and FILAMENT switch at ON).
13. Set RF-103 PLATE switch at ON. At the exciter, select the first channel to be aligned. Observe that the RF-103 has channelized and the correct CHANNEL light is illuminated.
14. Set RF-103 METER SELECTOR switch at OUTPUT. Adjust the exciter for reduced output (20-30 watts) using AM mode with no modulation or CW mode with reduced transmit audio gain.
15. Key the exciter and adjust the appropriate channel tune resistor on the Program/Junction Board for a peak indication on the output meter.

Repeat steps m through p for the remaining channels.

For exciters with channel control (RF-220), set the Local/Remote switch at Remote. For other types of exciters (RF-301, etc.), leave the switch at Local.

The post installation procedures are now complete. Refer to the Local/Automatic or Remote/Automatic operating procedures located at the front of this manual and make a test transmission on each channel.

Manual Operation Checkout

Perform the following post installation procedures for units to be operated manually (no automatic pre-programmed or pre-tuned channel control):

1. Check that the Local/Remote switch is set at Local. Set CHANNEL SELECTOR switch at a neutral (unmarked) position, FREQUENCY MC switch at the desired frequency band, and PLATE switch at ON. Set METER SELECTOR switch at OUTPUT.
2. Preset the Tuning Reference Meter with the TUNING switch to 50. If the operating frequency is in the lower 50% of the selected band range, tune toward the upper end of the Tuning Reference Meter for a peak. If the operating frequency is in the upper 50% of the band, tune toward the lower end of the Tuning Reference Meter for a peak.
3. At the exciter, select the operating frequency and adjust for a reduced output level (20-30 watts) using the AM mode with no modulation or CW with reduced transmit audio gain. Key the exciter and peak the output indication with the TUNING switch.
4. Increase the exciter drive until the RF-103 indicates 370 watts output. Unkey the exciter and record the Tuning Reference Meter indication. Repeat for other operating frequencies and record the meter value.

The post installation procedures are now complete. Refer to the Manual Operating Instructions at the front of this manual.

CIRCUIT DIAGRAMS

The document includes detailed circuit diagrams illustrating the internal workings of the RF-103A. These schematics cover various sections including the output network, antenna voltmeter, main frame connections, input board, filament board, servo amplifier/limit circuit, and power supply. They detail component interconnections, signal paths, and voltage levels, providing essential information for maintenance and troubleshooting.

Figure 3.2 Installation Connection Points

This diagram shows the rear panel connection points for the RF-103, including:

• J21: RF INPUT FROM EXCITER
• J22: RF OUTPUT TO ANTENNA COUPLER
• J23: EXCITER (Control Input)
• J24: ANTENNA COUPLER (Control Output)
• J25: AC POWER INPUT
• GROUND terminal
• EXHAUST FAN B4

Figure 3.3 Plugs P1 and P2 Installation Location and Wiring Diagram for Various Power Line Voltages

This figure illustrates the location of plugs P1 and P2 and provides wiring diagrams for different primary power voltages (105VAC-110VAC, 110VAC-120VAC, 120VAC-130VAC, 210VAC-220VAC, 220VAC-230VAC, 230VAC-260VAC). It notes that P1 and P2 are wired identically.

Figure 3.4 Coax Relay K1 Rf Connections

This diagram shows the RF connections related to the coax relay K1, including the input attenuator assembly, RF input from exciter (J12A/P21), and RF output (J26/P12).

Figure 3.5 RF-103 Simplified Keyline Interlock Diagram with System Connections

This diagram illustrates the keyline interlock system, showing connections between the RF-103, exciter, and antenna coupler. It depicts the keyline, key relay, coax relay, door interlock switch, plate interlock switch, and servo amplifier limit circuit, detailing how these components interact to ensure safe operation.

Figure 3.6 Channel Vs Frequency Band Connections

This figure shows the connections between channel pins (E1-E10, E11) and frequency band jacks for programming channels. It includes a table listing the channel pins and their corresponding functions (CHAN 1 through CHAN 10) and a note about multiplier jacks.

Figure 4.1 - Main Frame Circuit Diagram and Voltage Chart

This is a comprehensive schematic of the RF-103's main frame, detailing the output network, antenna voltmeter, various input/output connections (from exciter, to antenna coupler), junction/program board connections, and control signals. It includes notes on capacitor and resistor values, front panel markings, power source voltage considerations, and switch positions.