Micom RM1200, FLN3175 Owner's Manual

RM1200

1kW Power Amplifier Option

Owner’s Guide

Table of Contents

Introduction................................................................................................................... 2

1 kW System Description............................................................................................... 2

Functional Description................................................................................................... 3

1 kW Amplifier ......................................................................................................... 3

Overdrive Protection................................................................................................. 4

High VSWR Protection.............................................................................................. 4

1 kW Amplifier Overheating Protection..................................................................... 4

Imbalance Protection ................................................................................................ 4

PS Unit ..................................................................................................................... 4

RM1200 Main Technical Characteristics ........................................................................ 5

Familiarization with RM1200 Equipment ....................................................................... 7

1 kW PA Front Panel................................................................................................. 7

1 kW PA LCD Functions ........................................................................................... 8

1 kW PA Rear Panel................................................................................................ 10

PS Front Panel......................................................................................................... 11

PS Rear Panel.......................................................................................................... 12

RM1200 Equipment Installation................................................................................... 13

Safety...................................................................................................................... 13

Installation Planning Guidelines............................................................................... 13

Grounding .............................................................................................................. 14

Power Requirements............................................................................................... 14

Cooling ................................................................................................................... 14

Installation Data ...................................................................................................... 14

Preparations for Installation.......................................................................................... 15

Installation Procedure .................................................................................................. 16

RM1200 Operation ..................................................................................................... 18

General................................................................................................................... 18

Preparations for Operation...................................................................................... 18

Calibration Procedure ............................................................................................. 18

Equipment Turn-On................................................................................................ 19

Operating Instructions............................................................................................. 20

Equipment Turn-Off................................................................................................ 20

6888882V04 1

Introduction

This manual covers the installation and operation of the MICOM RM1200 1 kW linear high-power RF
amplifier unit, FLN3175. RM1200 uses the MICOM RM125 or RM125R, part of the MICOM-3 line of
HF-SSB radio sets, as exciter and controller to implement a complete 1 kW transceiver.

The manual covers only procedures specific to the MICOM RM1200. For procedures related to the
RM125 and RM125R, refer to the “RM125/RM125R Owner’s Guide”, Publication 6888882V02. The
other procedures, which are common to the whole MICOM-3 product line, are described in the
“Owner’s Guide, MICOM-3F/3T/3R HF-SSB Transceivers”, Publication 6886867J01, and in other
MICOM-3 Supplements that cover optional features applicable to your radio set.

Note

If you are using a different type of exciter/controller, use its vendor’s manual
instead of the MICOM-3 publications.

1 kW System Description

The RM1200 1 kW power amplifier, FLN3175, expands the MICOM-3 product line by offering
higher transmit power (up to 1 kW, PEP and average), and thus longer reach and improved
communications under bad propagation conditions and/or strong interference.

RM1200 consists of two units intended for rack mounting, together with the exciter unit: 1 kW RF
linear power amplifier and AC-powered PS unit. The equipment is well suited for base station
applications, and can be directly connected to a wide range of broadband or tuned antennas,
including whip, dipole, traveling wave, delta, and semi-delta antennas.

Upon power-up, the RM1200 uses a low-level RF pilot signal from the exciter to automatically detect
the incoming frequency and select the optimum harmonic filter band in accordance with the
operating frequency. The frequency detection and filter switching is quite rapid, a capability needed
for ALE and adaptive communication modes.

The RM1200 is optimized for operation in conjunction with the RM125 or RM125R radio set as
exciter and controller, using a dedicated communication interface and a flexible handshaking
protocol (to use these capabilities, order the special interface cable kit, option G156, for connecting
the 1 kW amplifier to the RM125/RM125R). The RM125/RM125R controls the 1 kW amplifier
operation, enables the operator to select the nominal transmit power, and the 1 kW amplifier
provides ALC feedback to adjust the RM125/RM125R drive power to the optimum level.

Before putting a new RM1200 into operation, it is necessary to calibrate
the system to obtain the correct transmit power (this calibration must

Caution

Although optimized for operation with the RM125/RM125R, RM1200 can be used with any HF-SSB
driver capable of providing the required drive power (approx. 40W), and appropriate interfacing.
Contact the manufacturer for details on the RM1200 interfacing requirements.

also be performed after either the exciter or the RM1200 is replaced).
Calibration instructions for the recommended exciter, RM125/RM125R,
appear in the Publication 2072-09538-00, “Radio Service Software (RSS)
User’s Guide” for RSS V3.0 and higher.

2 6888882V04

Protection circuits monitor the various operating conditions, and prevent damage to the 1 kW
amplifier by taking appropriate action, in accordance with the detected problem.

The 1 kW amplifier has several status indicators, and a front-panel LCD that enables the operator to
monitor the RM1200 operation. This LCD can be used to read the actual forward and reflected
power (or VSWR), and report problems such as the activation of protection circuits or technical
malfunctions. The LCD and the status indicators indicate the type of problem that has been detected,
thus helping the operator correct it.

In addition, the 1 kW amplifier has a serial RS-232 asynchronous interface that can be used for
maintenance and calibration: the program needed to use this interface is stored in the 1 kW
amplifier, and therefore any data communication terminal (or PC emulation program, for example,
the HyperTerminal utility available on PCs running under Microsoft Inc. Windows®) can be used.

The 1 kW amplifier is active only in the transmit mode: when not powered, in the receive mode, and
also after the protection circuits are activated, the 1 kW amplifier switches to the bypass mode, and
directly connects the radio set to the antenna system.

Functional Description

1 kW Amplifier

The 1 kW amplifier consists of the following main functions:

• Linear RF power amplifier covering the HF band. The RF amplifier consists of 4
independent amplification modules, whose outputs are combined to obtain the
required RF output power. The RF drive signal, applied to the RF IN connector, is
amplified to the appropriate level, as selected on the RM125/RM125R.

• Harmonic filter. This is a low-pass filter whose purpose is to attenuate harmonics and
other undesired signals at frequencies above the actual operating frequency, before
the amplified output signal is applied to the RF OUT connector. The filter has 8
sub-bands: the filter that fits the operating frequency is automatically inserted in the
transmit path. The required frequency information is received from the
RM125/RM125R; in addition, the 1 kW amplifier measures the actual frequency of the
RF drive signal as part of its tuning process (if the frequency cannot be measured, the
highest band is selected).

• Bypass circuits. These circuits automatically bypass the 1 kW amplifier and establish a
direct path between the RF IN and RF OUT connectors when power is not available,
or a critical malfunction is detected.

• Control circuits. These circuits control 1 kW amplifier operation, interface with the
exciter/controller unit (RM125/RM125R), and take action to protect the amplifier
when necessary.

• Cooling subsystem, includes internal fans that enable operation over a wide range of
temperatures.

6888882V04 3

Overdrive Protection

The 1 kW amplifier requires a nominal drive power of approx. 40W. When operating the 1 kW
amplifier with the RM125/RM125R as driver, the input power is automatically adjusted by an
automatic level control to achieve optimal operating conditions for the amplifier.However, if the
input drive power exceeds about 80W (either because incorrect setting of the operating conditions
when using another’s vendor’s driver, incorrect connections or other possible faults), the protection
circuits prevent damage to the 1 kW amplifier by bypassing it.

High VSWR Protection

To obtain maximum forward power, the RM1200 should be connected to a low VSWR antenna system.
In case of excessive VSWR, for example, because of mismatch or damage to antenna system and/or
feed cables, the ALC circuits prevent damage by reducing the transmit power to safe values. Thus, the
RM1200 will always attempt to transmit at the maximum safe power in case of mismatch.

However, in case of excessive mismatch (for example, short or open circuit), the protection circuits
switch the 1 kW amplifier to the bypass mode: in this case, the transceiver is directly connected to the
antenna. This enables normal reception, as well as transmission, albeit at the lower power levels an
RM125/RM125R (or the transceiver used as exciter) can provide.

1 kW Amplifier Overheating Protection

Special circuits protect the 1 kW amplifier against overheating. If the temperature is too high to
enable full-power operation, the output power is automatically halved, until the temperature returns
to normal. However, if the temperature exceeds the maximum allowed limit and damage may be
caused, the protection circuits are activated and bypass the amplifier.

Imbalance Protection

When a fault, power failure or other type of failure prevents normal operation of one or more of its
internal amplification modules, the 1 kW amplifier is automatically bypassed.

PS Unit

The PS unit is a custom design that includes 6 JWS-600-48 standard power supply modules
manufactured by Lambda Inc. (see manufacturer’s manual for complete information on these
modules), contained in a compact chassis suitable for installation in 19” racks. The individual modules
automatically share the load, without any special alignments. The assembled PS unit has been
assigned a custom-design manufacturer number (YM-02-670B).

The PS unit operates on 110/220 VAC, 50/60 Hz. The AC input voltage range is automatically
switched between 110 and 220 VAC, and therefore the equipment can be used in the United States
of America as well as in other countries. Internal cooling fans enable operation over a wide range of
temperatures.

The PS unit includes two independent power supply subsystems, each providing +45V to two of the
four amplification modules in the 1 kW amplifier. Protection circuits monitor each output, and
provide indications on front panel indicators in case the output voltages deviate by more than 25%
from the nominal value; if an output voltage increases beyond the maximum limit, the corresponding
power supply subsystem is turned off, to prevent damage to the 1 kW amplifier.

4 6888882V04

RM1200 Main Technical
Characteristics

This section presents the main technical characteristics of the RM1200. if you need additional details,
contact the manufacturer or your local representative.

General

Operating Modes

Transmit frequency range

Maximum transmit duty cycle

Control and maintenance
interfaces

Number of system units

Exciter type

• Transmit mode (PTT controlled)

• Bypass mode (input connector

connected to output connector with
RM1200 not powered, in the receive
mode, or after protection is activated)

• Tuning (automatic detection of transmit
signal frequency)

1.6 to 30 MHz

Continuous transmission

• Serial RS-232 asynchronous maintenance
port for dumb terminal (control program
contained in 1 kW amplifier)

• Control and status port for interfacing to
the RM125/RM125R as driver

• 1 kW RF linear power amplifier

• AC-powered PS unit, Lambda

YM-02-670B

• RM125/RM125R (recommended)

• Any HF-SSB radio set capable of

providing sufficient drive power and
compatible control interface

1 kW Amplifier
Electrical
Characteristics

6888882V04 5

Transmit power (PEP and average)

Input drive power

Nominal input and output
impedance

Intermodulation products

Non-harmonic products

Harmonics

User-selectable:

• Max: 1000W

• High: 700W

• Medium: 500W

• Low: 250W

• 40W nominal, maximum 80W

• Pilot tone for operating frequency

detection: 5W nominal

50 Ω

Less than -25 dB below each tone

Less than -60 dB

Less than -50 dB

Load mismatch

• Full transmit power for VSWR up to

1.3:1

• Reduced transmit power for higher
VSWR

• Full protection against short/open circuit

Dimensions

PS Unit Main
Characteristics

Overheating protection

Operating voltage

Power requirements

Cooling

Height

Width

Depth

Weight

Output voltage

Operating voltage

AC power requirements

Cooling

• Reduced transmit power for high
temperature

• Bypass in case of excessive temperature

45 to 48 VDC from PS unit

• Maximum 2000W in SSB mode

• Maximum 3500W in CW mode

Forced air cooling

221 mm/8.7 inch

482 mm/19 inch

492 mm/19.4 inch

25 kg/55 lbs

45 VDC nominal

110 /220 VAC, 50/60 Hz, with automatic
switching

Maximum 5000W

Forced air cooling

6 6888882V04